A Specialist Periodical Report
Inorganic Chemistry of t h e Main-group Elements Volume 3
A Review of the Literature P...
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A Specialist Periodical Report
Inorganic Chemistry of t h e Main-group Elements Volume 3
A Review of the Literature Published between September 1973 and September 1974 Senior Reporter C. C. Addison
Reporters
M. G. Barker G. Davidson M. F. A. Dove P. G. Harrison P. Hubberstey A. Morris R. J. Pulham D. B. Sowerby
All of: Department of Chemistry, University of Nottingham @ Copyright 1976
The Chemical Society Burlington House, London W I V OBN
ISBN 0 85186 772 3 ISSN 0305-697X Library of Congress Catalog Card No 72-95098
Filmset in Northern Ireland at The Universities Press, Belfast Printed by photolithography, and bound in Great Britain at The Pitman Press, Bath
Preface The general layout of Volume 3 follows closely that which has been successful in the first two volumes, so that discussion of the elements takes place in eight chapters. Each chapter is concerned with one of the Main Groups of the Periodic Table, and the volume is again written by members of the Department of Chemistry in the University of Nottingham. Volume 2 was larger than Volume 1, and there are so many current topics of interest that it would have been easy, on scientific grounds alone, to continue this expansion. However, other factors, largely economic, now arise which require that future volumes should be limited in size, and in consequence Volume 3 is appreciably smaller than Volume 2. This has been achieved to a small extent by treating groups of references together in tables and lists, but to a greater extent by considering carefully the amount of physical data which is appropriate to this particular Report, and limiting such data to the minimum necessary to illustrate the property under discussion. More important still, the authors are no longer able to claim that their articles are comprehensive. Instead, we have attempted to include all themes of current interest, and hope that it will be possible to deal with items which are at present chemically isolated, by back reference in a future volume. The authors have also discussed whether there are any general trends which have become apparent. Although there are variations from Group to Group, there is an overall impression that the quantity of worthwhile published research in the area of Main-group chemistry has diminished somewhat during the past year. C . C . Addison.
...
111
Con tents Chapter 1
Elements of Group I
1
By R. J. Pulham
1
Introduction
1
2
TheAlkaliMetals
1
3
Alloys and Intermetallic Compounds
7
4
Solvation of Alkali-metal Ions Aqueous Solvation Non-aqueous Solvation
9 9 13
5
Compounds containing Organic Molecules or Complex Ions
17
6
Alkali-metal Oxides
35
7
Alkali-metal Halides
38
8
Lithium Compounds
42
9
Sodium Compounds
46
10
Potassium Compounds
51
11
Rubidium Compounds
53
12
Caesium Compounds
54
13
Molten Salts Nitrates Halides
55 56 57
Elements of Group II
64
Chapter 2
By R. J. Pulharn
1
Beryllium
64
2
Magnesium
70
3
Calcium
79 V
Contents
vi
4
Strontium
86
5
Barium
89
Chapter 3 1
2
3
4
Elements of Group Ill By G. Davidson
95
Boron General Boranes Borane Anions and Metallo-derivatives Carbaboranes Metallo-carbaboranes Compounds containing B-C Bonds Aminoboranes and Other Compounds containing B-N Bonds Compounds containing B-P Bonds Compounds containing B-0 Bonds Compounds containing B-S or B-Se Bonds Boron Halides Boron-containing Heterocycles Metal Borides
95 95 96 100 106 116 129
Aluminium General Aluminium Hydrides Compounds containing A1-C Bonds Compounds containing A1-N or Al-P Bonds AI-S, or Compounds containing A1-0, AI-Se Bonds Aluminium Halides
131 136 138 143 145 150 158
159 159 160 161 163 165 172
Gallium General Gallium Hydrides Compounds containing Ga-C Bonds Compounds containing Ga-N, Ga-P, or Ga-As Bonds Compounds containing Ga-0 or Ga-S Bonds Gallium Halides Other Gallium Compounds
175 175 175 176
Indium General Compounds containing Bonds between In and Group VI Atoms
181
176 177 179 180
181 181
vii
Contents Indium Halides Other Indium Compounds Thallium
5
Thallium(n1) Compounds Thallium(1) Compounds Other Thallium Compounds
Elements of Group IV
Chapter 4 1
2
By P. G. Harrison a n d P. Hubberstey Carbon Carbon Allotropes Structural Studies Chemical Studies Graphite Intercalation Compounds Alkali Metals Halogens, Halides, and Oxides Methane and its Substituted Derivatives Theoretical Studies Structural Studies Spectroscopic Studies Chemical Studies Formaldehyde and its Substituted Derivatives Formaldehyde, Carbonyl Halides, etc. Formic Acid and Formates Derivatives of Group VI Elements Oxides, Sulphides, and Related Species Carbonates, Thiocarbonates, and Related Anions Derivatives of Group V Elements Cyanogen, Cyanides, Cyanates, and Related Species Silicon Germanium, Tin, and Lead Hydrides of Silicon, Germanium, and Tin Silicon Solid-state Chemistry Silicon Dioxide Silicates Germanium(rv), Tin(rv), and Leaduv) Oxides, and Related Germanates and Stannates Molecular Silicon(rv)-, Germanium(1v)-, Tin(Iv)-, and Lead(rv)-Oxygen Compounds Oxides Alkoxides and Related Derivatives Carboxylates and Oxy-acid Derivatives
183 183 184 184 185 188
190 190 191 193 195 197 198 199 201 20 1 202 205 207 212 212 215 215 215 220 223 223 226
226 229 229 232 240 24 1 241 243 249
...
Contents
v111
Halides of Silicon, Germanium, Tin, and Lead Pseudohalide Derivatives of Silicon, Germanium, Tin, and Lead Sulphur and Selenium Derivatives of Silicon, Germanium, Tin, and Lead Nitrogen and Phosphorus Derivatives of Silicon, Germanium, and Tin Derivatives of Silicon, Germanium, Tin, and Lead containing Bonds to Main-group Metals Derivatives of Silicon, Germanium, Tin, and Lead containing Bonds to Transition Metals Bivalent Derivatives of Silicon, Germanium, Tin, and Lead Unstable Silylenes and Germylenes Halogen Derivatives Oxygen Derivatives Sulphur Derivatives Nitrogen Derivatives Interactions of Bivalent Germanium and Tin Compounds with Transition-metal Derivatives
3
Chapter 5
Intermetallic Phases Binary Systems Ternary Systems
Elements of Group V
25 1
258 259 264 275 280 294 294 295 298 303 305
305 309 309 311
314
By A. Morris and D. €3. Sowerby
1
Nitrogen Elementary Nitrogen Bonds to Hydrogen N H and NH2 Species NH, NH: NH,OH and Derivatives N2H2and its Derivatives N,H, and Derivatives Bonds to Nitrogen hides Other Species Bonds to Oxygen N*O NO NOz-NzO,
314 3 14
316 3 16 316 318 318 320 321 323 323 325 325 326 326 327
ix
Contents
Nitric Acid and Nitrates Fremy’s Salt and Derivatives Nitrogen Oxides and Atmospheric Chemistry Bonds to Fluorine Bonds to Halogen
2
3
Phosphorus Phosphides Hydrides Compounds containing P-P bonds Bonds to Boron Bonds to Carbon Phosphorus(rr1)Compounds Phosphorus(v) Compounds Bonds to Silicon Bonds to Fluorine Phosphorus(rr1)Compounds Phosphorus(v) Compounds Oxyphosphorus(v)Compounds Bonds to Chlorine Phosphorus(II1)Compounds Phosphorus(v) Compounds Oxyphosphorus(v)Compounds Bonds to Bromine or Iodine Bonds to Nitrogen Phosphorus(Ir1)Compounds Phosphorus(v) Compounds Compounds containing P-N-P Bonds Compounds containing PnNn Rings Compounds containing Heteroatom Ring Systems Bonds to Oxygen Compounds of Lower Oxidation State Phosphorus(v) Compounds Monophosphates Apatites Diphosphates Cyclic Metaphosphates Polyphosphates Phase Studies Powder Diffraction Data Bonds to Sulphur or Selenium Arsenic Arsenic and Arsenides Bonds to Carbon
329 333 333 335 336 337 337 337 338 340 341 34 1 343 344 344 344 347 350 35 1 35 1 352 354 357 357 357 360 3 62 363 370 371 37 1 372 375 378 378 379 379 3 80 38 1 381 3 84 384 385
Contents
X
Halogens Nitrogen Oxygen Sulphur or Selenium
386 388 389 392
Antimony Antimony and Antimonides Bonds to Carbon or Nitrogen Bonds to Halogens Antimony(n1) Compounds Antimony(v) Compounds Bonds to Oxygen Bonds to Sulphur, Selenium, or Tellurium Bismuth
393 393 393 395 395 397 399 400
Bonds Bonds Bonds Bonds
4
5
Chapter 6
to to to to
Elements of Group VI
40 1
403
By M. G. Barker
1
2
403 Oxygen The Element 403 405 Ozone 406 Oxygen Fluorides Hydrogen Peroxide 406 407 Other Hydrogen-Oxygen Compounds Water 408 Sulphur 409 409 The Element Sulphur-Halogen Compounds 412 41 5 Sulphur-Oxygen-Halogen Compounds 418 Sulphur-Nitrogen Compounds 418 Linear Compounds 423 Cyclic Sulphur-Nitrogen Compounds Cyclic Compounds containing Sulphur, Ni427 trogen, and other Elements in the Ring 430 Other Sulphur-containing Ring Compounds 43 1 Sulphur-Oxygen Compounds 43 1 Binary Oxides 433 Sulphates Fluoro- and Chloro-sulphates 436 Other Oxyanions of Sulphur 437 439 Sulphuric Acid and Related Compounds Sulphides 440 Hydrogen Sulphide 440 Metal Sulphides 44 1 Group IV Metal Sulphides 443
xi
Contents
3
4
Group V Metal Sulphides Other Metal Sulphides Other Sulphur-containing Compounds
446 447 448
Selenium The Element Selenium-Oxygen-Halogen Compounds Selenium-Oxygen Compounds Selenates and Selenites Acids of Selenium Selenides Other Compounds of Selenium Tellurium
45 1
The Element Tellurium-Halogen Compounds Compounds containing Tellurium-Oxygen Bonds Tellurides
Chapter 7 The Halogens and Hydrogen
45 1 454 45 5 456 459 459 46 1 462 462 463 467 467
469
By M. f. A. Dove
1
2
Chapter 8
Halogens Elements Halides Interhalogens and Related Species Oxide Halides Oxides and Oxyanions Hydrogen Halides
469 469 473 476 48 1 483 487
Hydrogen Protonic Acid Media Hydrogen-bonding Miscellaneous
489
The Noble Gases
495
489 490 494
By M. f. A. Dove
The Elements
495
Krypton, Xenon, and Radon@)
496
Xenon(rv)
498
Xenon(w)
499 502
Author Index
503
1 Elements of Group I BY R. J. PULHAM
1 Introduction In this chapter individual references which are inter-related are grouped together to make assection and, therefore, reference to several alkali metals may feature in a single section. Each reference, however, appears oncG only ill not be within this chapter so that, if described in one section, it w duplicated in any other. Single references to topics are presented systematically in the section on the appropriate metal. The elements of Groups I and I1 are so closely linked in some instances that a section describing them jointly is presented to avoid duplication in Chapter 2. Such a case is the section on ‘Molten Salts’, which covers the chemistry of the molten salts of both Groups I and I1 but is presented only in this chapter.
2 The Alkali Metals The electron afFinities/eV (&0.05),determined from the threshold energies of the photo-detachment cross-sections of the atomic negative ions, are 0.61, 0.53,0.50,0.48,and 0.47 for Li, Na, K, Rb, and Cs, respectively. The values for Rb and Cs were obtained by extrapolating the cross-section below 0.5 eV. All values for the alkali metals are abstracted from a set covering the elements of the short periods.’ The reaction cross-sections of alkali-metal atoms with Br, have been obtained by direct measurements of alkali-metal atom decay rates. The alkali-metal atoms were produced in the presence of a known amount of Br, by photodissociating the bromide of the particular alkali-metal atom with a short pulse of U.V. light. As the atoms reacted with Br, their decay rate was determined from the transmission of alkali-metalatom resonance light through the vapour. The reaction cross-sections/& as computed from the decay rates are Na, 116; K, 151; Rb, 197, and caesium, 204, and are accurate to ca. 15%.’ Theory and experimental practice in the field of soft X-ray emission from metallic solids have been briefly reviewed, D. Feldmann, R. Rackwitz, E. Heinicke, and H. J. Kaiser, Phys. Letters (A), 1973,45,404. J. Maya and P. Davidovits, J. Chem. Phys., 1973, 59, 3143.
1
2
Inorganic Chemistry of the Main -group Elements
and measurements on a number of systems including Li, Na, and Mg, are critically evaluated. Comparison is made with the results of other techniques and theory to establish the pertinence of soft X-ray measurements and to indicate specific guidelines for further enhancing their value. An exhaustive annoted index of measured spectra is also provided.' X-Ray photoelectron spectra of Li and Na obtained in ultrahigh vacuum show rich plasmon structures on all peaks. Both the photoemission and Auger peaks showed large extra-atomic relaxation energies. The sodium valence band showed an approximately E '', behaviour, as expected for a nearly free-electron metal, but it has some a n ~ m a l y Further .~ X-ray photoemission spectra of valence and core electrons in Na and NaOH have been measured from clean and oxidized Na films. Clean metal surfaces were prepared by sequential evaporation to give films contaminated with only half a monolayer even after several hours. From these films an analysis of lineshapes of core-electron spectra revealed evidence for the effects of electron-hole interactions. The valence band of Na was determined as free-electron-like again, with an occupied bandwidth in hgreement with theory. Accurate binding energies/eV for the core Na, 2p, 2s, and 1s electrons are 30.58k0.08, 63.57*0.07, and 1071.76 0.07, respectively. By comparison with core-level spacings in the free ion and crystal, the measured 2s and 1s electron binding energies in the metal were anomalously large. The valence band of NaOH resembled that of H,O(g) after shifting the vapour spectrum to lower binding energies. Evidence was found for weakly chemisorbed N, on the NaOH surface.' The work function of rubidium films deposited on quartz substrates at lo-'" Torr has been determined photoelectrically as 2.261 *O.OlS eV at 140 K. On warming to 1SO-200 K, an irreversible decrease occurred in photoelectric yield.6 Semi-empirical potential-energy surfaces have been calculated for the alkali-metal atom-dimer exchange reactions of Li and Na. The surfaces exhibit a potential well at small internuclear distances which extends into the entrance and exit valleys without an energy barrier. The alkali-metal triatomic complex is deemed most stable in the linear or near-linear configuration but remains stable, however, over all bent configurations. In the mixed complex, the configuration with the lighter Li in the central position is the more stable, i.e. NaLiLi is more stable than LiNaLi, and NaLiNa is more stable than NaNaLi.' It is considered that the diatomic ox molecular orbitals rather than the p atomic orbitals can probably function as . the metallic orbitals in the simplest account of the Pauling valence-bond theory of electron conduction in alkali metals.' High-temperature vapour pressures and critical points have been determined for potassium and
*
*
A . J. McAlister, R. C. Dobbyn, J. R. Cuthill, and M. L. Williams, Report 1974, NBS-SP-369. S. P. Kowalczyk, L. Ley, F. R. McFreely, R. A. Pollak, and D. A . Shirley, Phys. Reu. ( B ) , 1973, 8, 3583. P. H. Citrin, Phys. Rev. (B),1973, 8, 5545. T. W. Hall and C. H. B. Mee, Phys. Status Solidi ( A ) , 1974, 21, 109. J. C . Whitehead and R. Grice, Mol. Phys., 1973, 26, 267. R. D. Harcourt, J. Phys. (B), 1974, 7, LA-L45.
Elements of Group I 3 rubidium. These lead to values of the enthalpy of vaporization of the K and Rb monomers at 0 K of 23.816’ and 20.3 kcal mol-l,lo respectively. The critical density of Rb is 0.347 f 0.002 g ~ m - ~ . ” The ignition and combustion of sodium has been reviewed’’ and the ignition temperatures of both sodium and potassium have been experimentally determined under conditions of slow heating in air, dropping the metal into hot air, and heating the metal under argon followed by exposure to air or oxygen.” In a theoretical treatment for solutions of non-metal X in a liquid alloy A-B, a parabolic dependence of solvation energy on the number of atoms A and B in the solvation shell of atoms X has been introduced in place of the usual linear relationship. Calculations of the activity coefficient of oxygen as a function of alloy composition using this modification agree with available experimental data. Although the concept is developed solely for oxygen (and other non-metals) in transition-metal alloys, it appears generally applicable to solutions of non-metals in liquid alkali metals a l ~ 0 . A I ~previous model for solutions of non-metals in liquid alkali metals has been extended. Electronegative non-metals are considered as anions in the liquid and solvated by cations. A method is given for calculating the Coulomb interaction between screened potentials round cations and anions in the free-electron gas of the metal using the Fourier convolution theorem.” The solubilities of the salts NaBr and NaI in liquid sodium have been determined from 150 to 450°C. The labelled halides (Na32Brand Na1311), as dried-down deposits on steel surfaces, were equilibrated with both static and flowing liquid sodium, which was subsequently analysed for halogen by gamma spectrometry. The solubilities, S/p.p.m. by weight, of NaBr and NaI respectively are given by the equations: log S = 9.00 - (5100 K/T) and
log S = 8.72 - (4650K/T)
The slopes of these lines provide partial molar enthalpies of solution of 97.5 f4.7 and 89.2 f2.6 kJ mol-’ for NaBr and NaI, respectively, where the thermodynamic reference state is the solid halide. The solvation enthalpies derived from these values are -265.6*9.9 and -225.0k7.9 kJ mol-’ for bromide and iodide ion, respectively. The salts are considered to dissolve in the metal as the dissociated ions, solvated by liquid metal, and the solutions show large deviations from ideal but small deviations from regular behaviour.16 The solubilities of potassium chloride in liquid potassium and in
lo l1
l2
l3 14
Is l6
W. R. Jerez, V. S. Bhise, S. DasGupta, and C. F. Bonilla, Proc. Symp. Thermophys. Prop., 6th, 1973, p. 353. V. S. Bhise and C. F. Bonilla, Proc. Symp. Themophys. Prop., 6th, 1973, p. 362. J. W. Chung and C. F. Bonilla, Proc. Symp. Themophys. Prop., 6th, 1973, p. 397. R. N. Newman, Ignition Combustion Sodium-Review, 1972, RD/B’/N229. V. A. Polykhalov and V. F. Prisnyakov, Atomnaya Energii, 1973, 35, 51. C. Wagner, Acta Met., 1973, 21, 1297. P. J. Gellings, A. Van der Scheer, and W. J. Caspers, J.C.S. Faraday 11, 1974, 70, 531. C. G. Allan, Report 1973, TRG-Report-2458.
Inorganic Chemistry of the Main-group Elements
4
solutions of potassium (20 and 30 atom %) in lead have been determined. Samples of the metallic melt were drawn through porous glass filters and converted into aqueous solutions, and the chloride ions were determined mercurimetrically, using diphenylcarbazone as indicator. The solubility of KCl increases in both solutions with increasing temperature, but dilution of potassium with lead causes a sharp decrease in the solubility of KCl. The low-temperature data for potassium are probably all that exist at present, and they are provided in Table 1.” Table 1 Solubility (s) of potassium chloride (mole ‘/o salt) in liquid potassium TemperaturePC s/(mole ‘/o salt) TemperaturePC . s/(mole YO salt) 158 180 183 214 240 3 10
7.4 x lo-’ 9.4 x 1 0 - ~ 1.02 x 1.25 x lo-’ 1.26 X lo-’ 2.98 x lo-’
370 390 395 508 600 625
5.10 X lo-’ 1.25 x lo-’ 1.26 x lo-’ 5.56 X lo-’ 1.71 3.30
The high-temperature physical properties of the sodium coolant and oxide fuel used in fast nuclear reactors have been reviewed, and the review includes enthalpy, heat capacity, vapour pressure, density, surface tension, viscosity, thermal conductivity, and speed of sound measurements. l 8 In the control of impurities in liquid-sodium coolant loops, analytical methods for measuring the impurity content have been reviewed.” Instruments for monitoring specific impurities, e.g. 0, H, and C, in sodium have been covered in another review on instrumentation for monitoring liquid sodium in nuclear reactors.” Fission products produced in Na-K coolant, and which form oxides, are present as a fine suspension, which tends to deposit on transition-metal surfaces. The deposited material, which can be radioactive, can be removed by water.’l The state and behaviour of the non-metals oxygen, hydrogen, and carbon in liquid sodium are currently under investigation. Preliminary results from concentration measurements on oxygen and hydrogen suggest that the ion 02-exists in the solution and reacts with hydrogen, the excess being converted into sodium hydride, thereby affecting the equilibrium pressure.22 The general equation: log S = 6.2571 - (2444.5 K/T) has been derived for the solubility of oxygen in liquid sodium by combining additional data with previously published results. The equation provides an
’’ V. Busse-Macukas,
A. G. Morachevskii, S. I. Statsenko, L. V. Rorisova, and V. I. Markin, Zhur. priklad. Khim., 1973, 46, 2300. l 8 M. G. Chasanov, L. Leibowitz, and S. D. Gabelnick, J . Nuclear Materials, 1973, 49, 129. lY H. Ullmaun, Kernenergie, 1974, 17, 5. ’O D. J. Hayes, J. Phys. (E), 1974, 7, 69. 2 1 R. A. Davies and J. Drummond, J. Brit. Nuclear Energy SOC., 1973, 12, 427. 2 2 K. Furukawa and H. Katsuta, Bussei Kenkyu, 1970, 13, 418.
Elements of Group I 5 enthalpy of solution of 11.184 kcal mol-' for oxygen in the metaLZ3The determination of traces of carbon and oxygen in sodium and caesium has been described, based on the reactions "C(y,n)"C and 160(y,n)150,respec8 bremsstrahlung tively, induced by irradiation of Na and Cs with ~ 3 MeV for 5 and 2 minutes, respectively. Because the half-lives of "C and "0 are 20.3 and 2.03 minutes, respectively, the sample can be etched free of surface contamination after irradiation. The method enables determination of oxygen and carbon concentrations as low as 0.3 p.p.m." Corrosion of transition metals by liquid alkali metals continues to be of interest. In the absence of dissolved oxygen in sodium, the solubilities of iron, nickel, and chromium in the alkali metal are slight. In the early stages of corrosion of stainless steel, corrosion rates are high, decreasing asymptotically to a steady-state value. Corrosion rate increases linearly with oxygen content in the liquid Similarly with vanadium in sodium. At 600°C the ternary oxide Na,VO, was observed on the surface of vanadium after immersion in sodium containing dissolved sodium oxide. The compound was identified by X-ray powder diffractometry, which was recorded through a matrix of sodium. Vanadium oxides were detected beneath the ternary oxide layer, and the change in lattice parameter of the vanadium substrate indicated the occurrence and amount of oxygen in solid Specific transition-metal oxides also react with sodium to give ternary oxides. Thus Nb& NbO,, NbO, and Ta205react at 400 and/or 600 "C to produce cubic Na3M04(M = Nb or Ta) together with M as equilibrium product^.^' Sodium vapour reactions appear less straightforward. Sodium gas at 3.3 x lo-' Torr reacted progressively with increasing temperature with a-Fe203and a- or P-NaFeOz to produce mixtures of metallic iron with (a) unidentified phase, (b) Na,,Fe,O,,, and (c) Na,FeO,. The magnetic properties and paramagnetic resonance spectra indicated that FeI'I exists in these compounds. Attempts to synthesize the unidentified phase in the pure state from reactions of sodium The bemonoxide, Na20, with NaFeO, and Fe,-, 0 were haviour of liquid potassium towards vanadium oxides has been assessed and compared with that of sodium and of lithium. The oxides V,Os and VO react at 63 "C,V203at 180 "C, but VO does not react below 400 "C, the maximum temperature studied. Potassium converted VO, into KVO, whereas v205 and V 2 0 3gave VO and KVO,, but both these compounds were oxidized by dissolved K,O to produce K3V04.29 The rate of reaction of hydrogen with stirred liquid sodium has been investigated at constant volume over the temperature range 160-295 "C and at pressures from 5.0 to 33.0 kN m-'. The rate of absorption is proportional to J. D. Noden, J . Brit. Nuclear Energy SOC.,1973, 12, 329. C. Engelmann, F. Nordmann, and G. Tinelli, Report 1973, CEA-CONF-2330. 2 5 J. R. Weeks and H. S. Isaacs, Adu. Corrision Sci. Technol., 1973, 3, 1. " M. G. Barker and D. J. Wood, J. Less-Common Metals, 1974, 34, 215. 27 M. G. Barker, A. J. Hooper, and D. J. Wood, J.C.S. Dalton, 1974, 55. '* A. Tschudy, H. Kessler, and A. Hatterer, Compt. rend., 1973, 277, B, 687. 29 M. G. Barker, A. J. Hooper, and R. M. Lintonbon, J.C.S. Dalton, 1973, 2618. 23
24
6
Inorganic Chemistry of the Main -group Elements
hydrogen pressure, confirming a first-order reaction. The activation energy for the reaction was 69.0 f 8.0 kJ mol-’, compared with previously reported values of 72.4, 71.6, 69.1, and 41.9 kJ m01-l.~’Previous work on the kinetics and thermodynamics of both the sodium-hydrogen and sodium-hydrogenoxygen systems has been reviewed, and possible reasons are suggested for the observed differen~e.~‘ The solubility of hydrogen (0.03-1 p.p.m.) in sodium has been redetermined by means of a meter based on the diffusion of hydrogen through a nickel membrane. The results, which include data of other workers, are summarized by the equation: log(S/p.p.m. by weight) = 6.067 - (2880 K/T) For unsaturated solutions the amount of hydrogen in solution is governed by the pressure. Over this region the Sievert’s constant, K , is slightly affected by temperature and is given by the equation:32 log(K/p.p.m. T0rr-l”)
= 0.860 - (122.0 K/T)
A new type of battery is described which utilizes alloys of lithium with lead, zinc, or tin as anode, fused LiCl-KCl as electrolyte, and chlorine as cathode. Liquid lithium alloys are used instead of pure lithium since they are more dense and sink below the electrolyte. The e.m.f. of this cell is much lower than in the conventional lithium-chlorine battery but cell structure is simpler, and the operating temperature and self-discharge rate are much lower.33 Lithium anode electrochemical cells can be made to operate at room temperature by using electrolytes of lithium salts in solvents such as POC13, SOCl,, and SO,Cl,. The solvents are compatible with both lithium and strong oxidants, including Cl,, CuF,, (CF),, and WO,, which can therefore be used as cathode materials.,, Further room-temperature lithium cells have been studied which employ solutions of LiBCl, in POC1, and of LiAlC1, in SOCl, as electrolytes. A novel feature of these cells is that during discharge the solvents POCl, and SOCl, are electrochemically reduced and behave as soluble cathode^.,^ The Dow sodium-sulphur battery is more conventional, and operates at 300°C with a high current and voltage effi~iency.,~ The alkali metals have a role to play in ammonia synthesis. The K,O promoter in the conventional NH, synthesis catalyst enhances the chemisorption of nitrogen and causes a hydrogen-promoted dissociation of the N, 30
31
32
33
34
35
36
A . C. Whittingham and M. R. Hobdell, Report 1973, RD/B/N-2548. A. C. Whittingham, Report 1973, RD/B/M-2546. D. R. Vissers, J. T. Holmes, L. G. Bartholme, and P. A. Nelson, Nuclear Technol., 1974, 21, 235. Z . Takehara, S. Morimoto, Y . Ito, and S. Yoshizawa, Intersoc. Energy Convers. Eng. Conf., Conf. Proc. 7th, 1972, p. 63. J. J. Auborn, K. W. French, S. Leiberman, V. K. Shah, and A . Heller, J. Electrochem. SOC., 1973, 120, 1613. W. K. Behl, J. A . Christopulos, M. Ramirez, and S. Gilman, J. Electrochem. SOC., 1973, 120, 1619. C. A. Levine, R. G. Heitz, and W. E. Brown, Intersoc. Energy Conuers. Eng. Conf., Conf. Proc. 7th, 1972, p. 50.
7
Elements of Group I
molecule. The electropositive promoter, metallic potassium deposited from the vapour phase on to pure iron, increased the rate of ammonia synthesis by a factor of ten. An extraordinarily high activity was obtained with promoted Ru supported on active carbon, although Ru was inactive without K. The effectiveness of alkali metals increased in the order NaCa>Zn>Cd. The symmetry of the H 2 0 molecule is reduced with increasing covalency of the cation-H,O bonding, and more favourable Y-OH2 - - - OH, groupings are formed.661.r. and Raman spectral data for water at various temperatures suggest that there is an equilibrium mixture of at least two components differing in the degree of hydrogenbonding, one with a free O H vibrational mode and another with hydrogenbonded O H at longer wavelength. A structure-breaking solute increases the number of non-bonded OH groups in water. At 37°C there is a greater number of free O H groups than at 25 "C. The addition of solute changes the fraction of non-bonded OH groups and the position of maximum intensity of any band due to these groups. Experimental spectra have been obtained for aqueous solutions of LiCl, NaCl, KC1, CsC1, and HCl and of LiN03, NaN03, KNO,, HN03, AgN03, LiClO,, NaClO,, AgClO,, and HClO,. Anions are generally structure-breakers whereas cations are structure-makers. Cations and anions appear to act independently of each other in modifying the structure of water, which depends on the size and charge of ion, and, in the case of transition metals especially, on strong specific interactions between the ion and one or more H,O m01ecules.~'A further near-i.r. study of the OH mode in water at 10, 25, and 40°C also indicates two types of water molecule; a non-bonded and a hydrogen-bonded species. At 25"C, an enthalpy change of 1.87k0.05 kcal mol-' is associated with this bondbreaking process. Changes in the spectra show that Li' and F- decrease the concentration of non-bonded H 2 0 molecules while the opposite is found for the other alkali-metal and halide ions. The relative order for the structurebreaking abilities of these ions is F- < C1- < Br- < I- and Li' < Cs' < Na' = Rb+ Rb' > K' > Na' > Li', which is the order of the effective ion size due to hydration. In mixtures of water with methanol, however, the mobilities of Na and Cs decrease with increasing concentration of methanol; in pure methanol, Na' is The mean molar volumes of solutions of NaI and KI more mobile than CS+.~, in water-diethylamine mixtures have been measured, and the results indicate that the salts break the water structure. A complex is indicated in solutions of KI in the mixed solvent but not for NaI.73 The extracting ability of alkylphenols (C,, b.p. 279-290 "C) for alkali-metal ions from basic aqueous solution decreases from Cs to K.74The solvation of alkaline-earthmetal halides during extraction by isoamyl alcohol has been investigated. MgCl,, SrI,, and calcium halides were extracted as hydrated species. The extent of solvation by water or alcohol molecules in solvates of calcium halides in the organic phase increased in the order chlorides < bromides < iodides. SrCl, and SrBr, were not hydrated but SrI, was. The extreme behaviour of the metal iodides can be explained by donor-acceptor interaction of iodide ion with Some aqueous systems that have been investigated are listed in Table 3.76-83 Non-aqueous Solvation.-Structural radii and electron-cloud radii, together with lattice enthalpies and enthalpies of solvation of ionic crystals, have been re~iewed.'~ The free energies of transfer, AGtr(K+),of potassium ions from water to 14 non-aqueous solvents have been reported, and they were derived from measurements in an electrochemical cell assumed to have a negligible liquid-junction potential. The essentially electrostatic nature of its solvation allows K' to be used as a model for non-specific solvent-ion interactions. A 71
72 73 74
75
" 77
7R
79
81 82
83
84
T. Erdey-Gruz, E. Kugler, K. Vasse-Balthazer, and I. Nagy-Czako, Magyar Kim. Folybirat, 1973, 79, 397. T. Mitsuji art3 Y. Tsujii, Nara Kyoiku Daigaku Kiyo Shizen Kagaku, 1973, 22, 19. V. I. Obraztsoy, A. A. Khrustaleva, and S. I. Belyaeva, Zhur. fiz. Khim., 1973, 47, 2175. V. E. Plyushchev, Z. S. Abisheva, G. N. Klevaichuk, L. 1. Pokrovskaya, and A. M. Reznik, Izuest. Akad. Nauk Kazakh. S.S.R., Ser. khim., 1974, 24, 41. T. S. Kazas and K. S. Krasnov, Zhur. neorg. Khim., 1974, 19, 1375. S . M. Arkhipov, N. I. Kashina, and V. A. Kuzina, Zhur. neorg. Khim.. 1973, 18, 3148. P. S. Bogoyavlenskii and E. D. Gashpar, Zhur. neorg. Khim., 1973, 18, 3125. P. I. Protsenko, S. D. Merkulova, G. P. Protsenko, and V. N. Trufanov, Zhur. neorg. Khim., 1974, 19, 529. V. Mozharova, V. A. Borovayk, and E. N. Pavlyuchenko, Zhur. priklad. Khim., 1973, 46, 2560. V. K. Filippov, K. A. Agafonova, and M. A. Yakimov, Zhur. neorg. Khim., 1974,19,1663. A. G. Demakhin, I. E. Zimakov, and V. I. Spitsyn, Zhur. neorg. Khim., 1974, 19, 245. A. A. Opalovskii, T. D. Fedotova, 0. G. Tyrshkina, and G. S. VoronYna, Zhur. neorg. Khim., 1973, 18, 1672. L. A. Azarova, E. E. Vinogradov, E. M. Mikhailova, and V. I. Pakhomov, Zhur. neorg. Khim., 1973, 18, 2559. E. C. Baughan, Structure and Bonding, 1973, 15, 53.
Inorganic Chemistry of the Main -group Elements Table 3 Aqueous systems that have been investigated 14
Components NaN0,-RbNO, KNOy-KHCO, RbN02-Mg(NOz), NaC1-BaCl, KCl-BaCl, CsBr-CdB r, CsI-CdI, CsCl- Ag C1-MeOH NaHFZ-MHF, (M = Na, K, Rb, or Cs) LiI0,-KIO,
Compounds NaN0,,2RbN03
Ref. 76 77 78 79 79 80
3CsBr,CdBr, 7CsBr,3CdBr2 CsBr,CdBr, 3CsI,CdIz 2CsI,CdI, CsI,CdI,,H,O CsAgC1,
80
2LiI03,KIO,
83
81 82
comparison of AGtr(K+)with AG,,(Ag') detects some specific interactions of the Ag+ ion with solvents. In this respect there is a striking difference between AG,,(Ag+) of 99.5 kJ mol-' and AGtr(K+)of 26.8 kJ mol-' for Some free transfer from water to dimethylthioformamide (SDMF) at 25 oC.x5 energies/kJ mol-' of transfer from DMF to NN-dimethylthioformamide (SDMF) at 2 5 ° C are Li', 64.0; Na+, 50.2; K', 37.2; Cs+, 23.4; Tl', -4.2; Ag', -87.0. Some of these values can be interpreted in terms of general interactions of hard and soft cations with hard and soft basic solvents. A linear relationship, AGtr(M+)= rn AG,(M+), is approximately obeyed by many cations for transfer to a variety of Alkali-metal-ion-0-donor-solvent cages exhibit low-frequency bands in the i.r. spectrum characteristic of the cation-0 polyhedra. Similar bands are seen with N-donors. The bands can be used to establish the nature of cation co-ordination and serve as probes to examine ion-solvent interaction^.^^ An analysis of the i.r. spectra of ternary mixtures LiC104-S,-S, showed a preferential solvation of the Li' ion by NH, and methylamines (S,) in MeCN o r THF (S,) and by MeCN (S,) in MeN0, (SJ. The appearance of wide bands in the ion-cage vibration region is related to the formation of different species [Li(S,),-, ( S 2 ) i ] + . The Li+-solvent molecule interaction energy decreases when the number of S, molecules in the first solvation shell increases. The mean composition of the first solvation shell was obtained from intensity measurements of the molecules not bonded to the ions; in favourable cases (S, = ND, or MeCN), the solvation number ofthe Li' ion in the pure solvent 85 86 87
D. A. Owensby, A. J. Parker, and J . W. Diggle, J . Arner. Chern. SOC., 1974, 96, 2682. R. Alexander, D. A. Owensby, and A. J. Parker. Austral. J . Chern., 1974, 27, 933. C. N. R. Rao, J. Mol. Structure, 1973, 19, 493.
Elements of Group I
15
could be estimated. The solvating power of the different bases decreases in the order NH, > MeNH2> Me2NH> Me3N> MeCN > MeN02 and involves both donor-acceptor and ion-dipole interactions.8s The i.r. spectra of solutions of LiClO,, NaClO,, and Mg(ClO,), in MeCN at 2100-2400 and 900-1200 cm-' show a shift in the vibration frequencies of C%N and C-C groups of MeCN toward higher frequencies due to inter-ion and ion-solvent interactions. The shift is independent of concentration, with magnitudes of 10, 21, and 36 cm-' for Na', Li', and Mg", respectively. The optical density at the absorption maximum of the shifted bands was used to determine the number of molecules of MeCN in the solvation shell. For Li, Na', and Mg" these were 4, 4,and 6, respectively. Ion pairs forming in solutions of LiC104 and NaC10, were not solvated, but the ion pair [MgClO,]' was solvated by one MeCN The 'H n.m.r. spectra of 0.3-2M-MC1 (M = Li, Na, K, Rb, Cs, or NH,) solutions in formic acid revealed a shift of the H-C proton signal to lower fields due to solvation effects. The cation solvate structure has been discussed, and the estimated solvation numbers are 4 for Li' and N&+, 6 for Na' and K', and 8 for Cs+, in agreement with geometric con~iderations.~~ 23 Na n.m.r. measurements have been obtained on solutions of sodium salts in 1,1,3,3-tetramethylurea, 1,1,3,3-tetramethyleneguanidine, sulpholane, THF, DMF, formamide, EtOH, MeOH, pyridine, and EtOAc. Chemical shifts were measured relative to aqueous 3M-NaCl. The direction, magnitude, and concentration dependence of the chemical shifts were strongly influenced by the solvating ability or donicity of the solvents. Formation of contact ion pairs depended not only on the dielectric constants of the solvents but also on their solvating abilities." Alkali-metal salts in propylene carbonate were also studied by 23Nan.m.r. and by i.r. spectroscopy. Cation-solvent vibrational frequencies were observed for Li', Na+, K', Rb', Cs', and The effect of pressure upon the complexation of lithium fluorenide ion pairs with triglyme (L) in Et,O has been studied by spectrophotometry, which revealed the presence of three equilibria: Li'Fl-
+ L = L Li'Fl-
Li'Fl-
+ L = Li'L
K2
F1- K ,
L Li'Fl- = Li'L F1- K, Here Li'F1- denotes the tight pair of lithium fluorenide; L Li'Fl- represents the externally triglyme-complexed tight pair, and Li'L F1- is the loose pair, the ions of which are separated by a triglyme molecule. At high triglyme
'' A. Regis and J. Corset, 89
90 91
92
Canad. J . Chem., 1973, 51, 3577. I . S. Perelygin and M. A. Klimchuk, Zhur. fiz. Khirn., 1973, 47, 2025. B. M. Rode, Z . anorg. Chem., 1973, 399, 239. M. S. Greenberg, R. L. Bodner, and A. 1. Popov, J . Phys. Chem., 1973, 77, 2449. M. S. Greenberg, D. M. Wied, and A. I. Popov, Spectrochim. Acta, 1973, 29A, 1927.
Inorganic Chemistry of the Main-group Elements 16 concentration, additional equilibria became important:93
L Li'F1and
+ L = L Li'L
F1-
Li'L Fl- + L = L Li'L F1-
Density measurements on solutions of alkali-metal salts in methanol from 0 to 60 "C over a wide concentration range show that the structure-breaking effect of the salts decreases in the order NaC10, > NaI, NaBr and KI > NaI > L~I.~" In an extension of previous calculations on the lithium cation-ammonia system, the energy for the reaction: Li'
+NH, = Li'(NH,)
has been calculated from CND0/2 and ab initio methods to be AE = -91.9 and 53.6 kcal mol-', respectively. Closer agreement with published experimental data for the equilibrium Li-N distance, r, in Li'(NH,) was obtained by the ab initio method ( r = 1.98 %.) than by the CND0/2 method ( r = 2.19 A)." The electrical resistivity of lithium tetra-amine, Li(NH,)", at 10-100 K and the magnetoresistance at 4.2 and 1.66 K have been measured, using a probeless mutual-inductance technique. The resistivity shows several anomalies in the solid phase, one of which has also been observed in thermal measurements and is associated with a f.c.c.-h.c.p. phase change. A second change near 69 K has not been observed thermally and is attributed to a magnetic transition. It is concluded that Li(NH,)" is probably an uncompensated metal with a high proportion of free carrier^.'^ Spectra of the solvated electron have been determined at -55, -65, and -75°C from solutions of Na in liquid ammonia and from 0.08 mol 1-' solutions of NaI in this liquid by extrapolation to infinite dilution. The spectra are consistent with absorption by two species but rule out the possibility that the second absorber incorporates only a single solvated electron. The data support the assumption that the second absorber is a binary combination of solvated electrons which is produced at all three temperatures and in solutions of both Na and NaI in ammonia. Spectra reported earlier appear to be characteristic of the second absorber and not the solvated e l e c t r ~ n . A ~ ' Raman study of liquid NH,, ND3, and ND,H, and of solutions of NaI and NaClO, in liquid NH3, has been made in which resolution of the envelopes in the N-H and N-D stretching regions suggests a two-species nature for the solvent The fundamental vibrational frequencies of liquid ammonia are perturbed primarily by anion interaction, with one exception, the symmetrical bending 93 94
95
96
97 98
B. Lundg;en, S. Claesson, and M. Szwarc, Chemica Scripta, 1974, 5, 60. B. S. Krumgal'z, 1. P. Kikitina, and 1. V. Kudryavtseva, Zhur. fiz. Khirn.,1974, 48, 1048. A. Stogard, Acta Chem. Scand., 1973, 27, 2669. M.D. Rosenthal and B. W. Maxfield, J. Solid State Chem., 1973, 7, 109. G . Rubinstein, T. R . Tuttle, jun., and S. Golden, J. Phys. Chern., 1973, 77, 2872. A. T. Lemley, J . H. Roberts, K. R. Plowman, and J . J. Lagowski, J . Phys. Chem., 1973, 77,
2185.
Elements of Group I
17
mode, v,, which exhibits a strong cation dependence. Low-frequency bands which are assigned to the symmetrical stretching mode of the solvated cation were observed for Li', Na+, Mg", Caz+,S F , and Ba2+at 241, 194, 328, 266, 243, and 2 15 cm-', re~pectively.~~ Ammonia pressure-temperature diagrams at 50-60 "C have been constructed for the systems LiBr,NH, (SJ-NH,LiBr,2NH3 (S,) and LiBr,2NH3 (S,)-NH3-LiBr,3NH3 (S,). The same kinetic characteristics were found in the interfacial reactions S, + S, or S, + S, when they were studied alone or together, provided that the nucleation of the last solid was slow. When nucleation was rapid, the total rate measured was at most equal to that of the energetically favourable reaction.loOIn solutions of potassium amide in liquid ammonia, an anomalously large transparency in the i.r. spectrum was observed at 1500-2300 nm which showed up at high KNH, concentrations and high hydrogen pressures. This was attributed to production of the solvated electron according to: NH;
+fHz= e- +NH,
It is suggested that a complex is formed between e-, KNH,, and some NH, molecules which are strongly linked, so that the normal bands of NH, at 1500-2300 nm diminish in intensity."' The reaction shown is claimed to limit the decomposition of metal solutions in liquid ammonia.102
5 Compounds containing Organic Molecules or Complex Ions The determination of the molecular structure by X-ray diffraction of complexes of lithium, sodium, potassium, rubidium, and caesium has been reviewed.lo3The complexing properties of macrocyclic ligands, in particular, form the basis of a second review.lo4 One current series of studies of the complexes formed- between alkali-metal ions and macrocyclic polyethers aims to determine the type of bonding site which will hold a specific metal ion in a hydrophobic environment. In this context, dibenzo-24-crown-8 (6,7,9,10,12,13,20,21,23,24,26,27-dodecahydrodibenzo[b,n]-1,4,7,10,13, 16,19,22-octaoxacyclotetracosine)reacts with two molecules of potassium isothiocyanate, giving C2,H,,O,,2KNCS. This compound shows the novel feature of having two potassium ions attached to one cyclic polyether at adjacent binding sites, an aromatic-type bond to potassium, and double nitrogen bridging from thiocyanate ions across two potassium ions. The structure was determined by three-dimensional X-ray K. R. Plowman and J. J. Lagowskii, J. Phys. Chem., 1974, 78, 143. R. De Hartoulari and L. C. Dufour, Bull. Soc. chim. France. 1973. 11, 2923 E. Saito, Report 1972, CEA-CONF-2228.. lo* J. Belloni and E. Saito, Report 1972, CEA-CONF-2230. lo' M. B. Hursthouse, in Molecular Structure by Diffraction Methods', ed. G. A. Sim and L. E. Sutton (Specialist Periodical Reports), The Chemical Society, London, 1973, Vol. 1, p. 791. 104 C. Kappenstein, Bull. SOC.c h m . France, 1974, 89. 99
100
18
Inorganic Chemistry of the Main -group Elements
analysis from diffractometer data. Crystals are monoclinic, of space group P2/c, with 2 = 2 in a unit cell of dimensions a = 9 . 9 0 2 , b = 18.55, c = 8.573 A, p = 106.9'. The environment of the K' ion is shown in Figure 1. The K-0 distances range from 2.732 to 2.979 A,compared with 2.8502.931 8, in the dibenzo-30-crown-10 complex and 2.777-2.955 8, in the
Figure 1 Diagrammatic representation of the co-ordination about the K' ions. The plane of the ligand ring shows only oxygen atoms. The benzene rings belong to two other ligand molecules in the crystal. Bond distances/A
K-0(1) 2.732(6) K-N K-0(4) 2.778(6) K-N' N-C K-0(7) 2.898 (6) K-O(7') 2.979(6) S-C K-O(10') 2.825(6) N-S 3.41( 1) K . . . K' (Reproduced from J.C.S. Dalton, 1973, 2469)
2.88(1) 2.87(1) 1.18(1) 1.60(1)
2.78(1)
(benzo- 15-crown-S),K+ complex. In the other complexes the metal is completely enclosed by ten oxygen atoms. In this complex it is available for interaction with anion and solvent, or, as in the crystal, with another source of electron density. Dibenzo-24-crown-8 is intermediate in size between dibenzo- 18-crown-6 and dibenzo-30-crown-10, and it is considered to be too large for formation of a 1: 1 complex and insufficiently flexible to wrap round a potassium ion, with the result that the 2 : 1 complex forms even in the presence of excess of ligand."' The structure of [Na(C2,H3606)(HZ0)2]Br is monoclinic, space group P i , with a = 10.32, b = 11.34, c = 6.67 A, '"' M Mercer a n d M. R. Truter, J.C.S. Dalton, 1973, 2469.
Elements of Group I
19
a = 116" 42', f3 = 109" 48', y = 100" lo', d(obs) = 1.43, and d(ca1c) = 1.406 for 2 = 1. This compound, dicyclohexyl-18-crown-6 sodium bromide, contains a six-oxygen 18-membered ring, and, since six-oxygen-membered rings preferentially select K' over Na', is an example of a complex in which the cation is in a selectively unfavourable environment. As before, the sodium ion is at a centre of symmetry and surrounded by an approximately planar ring of the six oxygen atoms of one ligand, with Na-0 distances of 2.67-2.97 A. Two water molecules (at Na-OH2 distances of 2.34 A), one above and one below the plane, separate the Na' ions from the bromide ions, creating a hexagonal-bipyramidal arrangement about the cation. The H,O molecules form hydrogen-bonds to bromide ions, giving an infinite chain structure.106 An investigation of the effect of solvent, presence of water, and ratio of reactants on the isolation of complexes between LiX (X= Br, I, or NCS) with benzo-15-crown-5 (1) and of NaX and KX with (l), dibenzo- 18-crown-6 (2), dibenzo-24-crown-8 (3), and dibenzo-30crown-10 (4) has led to several new complexes, particularly those with two
-
Table 4 Summary of known compositions of LiX-, NaX-, and KX-crown ether complexes. Ratios are quoted as metal: ether Li
X= (1)
(2) (3) (4)
' I { I
K
Na A
Br
NCS
3
1:1,HzO l : l , H z O 1:1,HzO 1:1, 1.SH2O 1:l 1:2 1:2 2:2 1:1,H20 1:1,2H20 1:1,2H,O 1 ~ 11.5H20 , 1:1 111 l:l,HzO 1:1, HzO 2: 1 2: 1 2:1,H20 2:l I:1 - 1:1,H2O
metal atoms to one ligand. In principle, synthesis of the complexes is simple. The ligand and salt are dissolved in a common solvent, e.g. ethanol, and warmed. Crystals separate on cooling. The criterion for complex formation was the isolation of a new phase which (i) if unsolvated had a higher melting point than the polyether and (ii) did not absorb at the characteristic i.r. frequency of the polyether. The known compositions of LiX, NaX, and KX complexes with the four macrocyclic ethers are collected in Table 4. Two lithium compounds with (1) are established as monohydrated 1:1 complexes, the bromide and iodide. No complexes were formed between lithium salts and the larger macrocyclic ethers.lo7 A generalized picture of the sodium and potassium complexes is shown in Figure 2. Complexes have also been prepared where X is an organic anion obtained by the deprotonation of 2-nitrophenol, 4-nitrophenol, 2,4-dinitrophenol, 2,4,6-trinitrophenol, 2-hydroxybenzoic acid, 2,6-dihydroxybenzoic acid, 2nitrobenzoic acid, or 2-aminobenzoic acid. For potassium, complexes of the Io6
lo'
M. Mercer and M. R. Truter, J.C.S. Dalton, 1973,2215. N. S. Poonia and M. R. Truter, J.C.S. Dalton, 1973, 2062.
20
Inorganic Chemistry of the Main -group Elements Pol y ether
M e t a l Ion, M+
Potassium
Sodium
I I1
I11
IV
Figure 2 Schematic representation showing stoicheiometry of polyether-MX complexes and the conformation of the polyether in the lattice. Solid dot stands for metal ion and the loop for polyether. (Reproduced by permission from J . Arner. Chem. SOC., 1974, 96, 1012)
type 1l2K1+X-, [( 1)&]+[X, as.]-, I(1),Kl'[X,HXl-, and [( 1),K]'[X, (HX),]are isolated. These are of comparable stoicheiometry to those when X - = Br-, I-, or NCS-. A point of difference is that the organic anion more effectively dehydrates M', so that even sodium is dehydrated in complexes with (1) and (3). For (2), where complexes of Na' and K' are constantly monohydrated, M' makes an easy fit into the hole of polyether, and water is able to interact with it from the vacant axial direction."' Preliminary polarographic investigations have been made on [(2)K]'SCN- and [(5)K]'C1-, where (5) is l,lO-diaza-4,7,13,16,2 1,24-hexaoxabicyclo[8,8,Slhexacosane. The NaNCS complex of the macrotetrolide antibiotic nonactin (6)
Me
(6) nonactin lo' log
N. S. Poonia, J. Amer. Chern. SOC., 1974, 96, 1012. F. Peter and M. Gross, Compt. rend., 1973, 277, C, 907
/
A
Elements of Group I
21 crystallizes in the space group C2/c, in which a = 15.55, b = 19.59, c = 15.31 A, p = 90". The environment of the sodium cation in this complex, C40012HS4,NaNCS, is shown in Figure 3. The X-ray crystal structure shows that the Na' ion is co-ordinated by four carbonyl oxygen atoms at distances of 2.438 and 2.395& and by four ether oxygen atoms at distances of
23
23
Figure 3 Bond lengths and bond angles are indicated in the right part of the figure, torsion angles in the left part for the complex of nonactin with sodium thiocyanate. (Reproduced by permission from Helv. Chim. Acta, 1974, 57, 664) 2.791 8, for 0 - 4 , (2.877 A in K complex) and 2.744 8, for 0 - 1 2 (2.812 A in K complex). The cubic co-ordination by eight near-equidistant oxygen atoms previously observed in the corresponding K complex is thus deformed but requires only very small changes in the ligand conformation. The carbonyl oxygen atoms, with their less crowded surroundings, seem better able to approach the sodium ion. This preference may be attributed to stronger dipole interaction with carbonyl- than ether-oxygen atoms. The preference of the ligand for K' depends mainly on the change in coordination from eight equidistant oxygen atoms in the K' complex to only four first neighbours in the Na' complex.11o Complexes of alkali and alkaline-earth metals with tripod ligands have 1'
M. Dobler and R. P. Phizackeriey, Helv. Chim. Acta, 1974, 57, 664.
22
Inorganic Chemistry of the Main -group Elements
been investigated. For the alkali metals these are the 2,2',2"-trimethoxytriethylamine-sodium iodide complex [NaI,N(CH,CH20Me),] and the 2,2',2"-triethanolamine-sodium iodide complex [NaI,N(CH,CH,OH),]. The crystal structures, respectively, are orthorhombic, space group Pna 2,, with one molecule per asymmetric unit, a = 14.77, b = 7.560, c = 13.570 A,and triclinic, space group P i , with two molecules per asymmetric unit, a = 7.693, b = 7.559, c = 9.294 A,a = 102.16", p = 91.47", and y = 93.02'. The crystal structure of NaI,N(CH2CHzOMe), consists of discrete molecules in which the sodium cation is pentaco-ordinate, as shown in Figure 4. Each
c9
Figure 4 Environment of sodium in the complex NaI,N(CH2CH20Me), (Reproduced by permission from Acta Cryst., 1974, B30, 56) sodium is bonded to all heteroatoms of one ligand and to the iodide ion. The Na-N distance is 2.45 A,the mean Na-0 distance is 2.35 A, and the Na-I distance is 2.97A.l" In NaI,N(CHzCH20H),, the sodium ion is heptaco-ordinate. Two OH groups of each molecule bridge two Na' ions. Each Na' is thus bonded to the four heteroatoms of one ligand molecule, two oxygen atoms of a neighbouring ligand, and to the iodide ion (Figure 5). The co-ordination polyhedron is an octahedron, with a seventh atom on one of the faces. The distances Na-0, Na-N, and Na-I are 2.516, 2.610, and 3.286 A, respectively.''* Complexes of 1,4-anhydroerythritol (cis-3,4dihydroxytetrahydrofuran) with the formulae (C,H,O,),,NaI, C,H,O,,NaClO,, and C,HsO,,NaSCN have been prepared, The perchlorate complex is orthorhombic, space group P2,2,2,, with a = 12.77, b = 7.28, c = 17.69 A,and 2 = 8. There are two crystallographically distinct molecules in the structure but they are approximately alike, and both furanoid rings (7)
(7) 1,4-anhydroerythritol. 111
'12
J. C . Voegel, J . C. Thierry, and R. Weiss, Actu Cryst., 1974. B30, 56. J. C . Voegel, J. Fischer, and R. Weiss, Actu Cryst., 1974, B30,62
Elements
Group 1
23
Figure 5 The environment and co-ordination of Na in NaI,N(CH2CH,0H), (Reproduced by permission from Acta Cryst., 1974, B30, 62) have the same near-envelope conformation. About both Na atoms there is a distorted octahedron of oxygen atoms comprising three from different ClOi ions, one pair of hydroxyl-oxygens from one carbohydrate molecule, and the etheric-oxygen from another, as shown in Figure 6. The Na-0 distances fall within the range 2.29-2.33 A. The Na-O(ether) distances are 2.36 and 2.35A; Na-O(perch1orate) distances range from 2.37 to 2.59A. Three of the C10, oxygen atoms are co-ordinated both to Na and C1, but one oxygen atom of every ion is not bound to Na, and these atoms with only one bond pack together but at distances too great to imply the
Inorganic Chemistry of the Main -group Elements
24
Figure 6 Part of the infinite net showing the co-ordination about one of the two kinds of Na atoms. The sets of atoms differ only slightly in their co-ordination geometry. In every Cloy ion one of the 0 atoms is bound only to C1, and two such atoms are depicted, together with a neighbouring hydroxyl 0, the packing distances (dashed lines) being indicated numerically. (Reproduced by permission from Actu Cryst., 1974, B30, 1590) existence of a chemical linkage.'" An X-ray diffraction analysis of a single crystal of the LiBr complex of antamanide, cyclo (-Val-Pro-Pro- Ala-PhePhe-Pro-Pro-Phe-Phe-) (8), crystallized from acetonitrile, shows the Li' to 8 9 10 1 Pro-Phe-Phe-Val-Pro
I
2
I
(all
L-)
Pro-P he-P he--A la-Pro 7 6 5 4 3
(8) Antamanide
be pentaco-ordinate, with four ligands to the carbonyl-oxygens of Val', Pro', Phe", and ProRand the fifth ligand to the N atom of the solvate MeCN, as shown in Figure 7. The compound C,,H,,N,,O,,(LiBr)(MeCN),2MeCN,
'
l3
R.E. Ballard, A. H. Haines, E. K. Norris, and A. G. Wells, Acta Cryst., 1974, B30, 1.590
25
Elements of Group I ANGLES DEG. 0(1)Li0(3) 8 6 O(3)LiO(6) 89 0(6)Li0(8) 84 0(8)Li0(1) 93 NLiO 11 96 NLiOt31108 NLiO(6 96 N Li0(8\ 104
Figure 7 The distances and angles for the ligands to the pentaco-ordinated Li' in LiBr,(antamanide) (Reproduced by permission from J . Arner. Chern. SOC., 1974, 96, 4000)
has space group P2,, with a = 11.912, b=23.206, c = 13.864& p = 110'0 45'5. Antamanide forms alkali-metal complexes with a high selectivity for sodium over potassium ions, and the Na'-antamanide complex is most stable in a lipophilic environment. Eight peptide groups are in the trans conformation, while the Pro2-Pro3 and Pro'-Pro* peptide linkages are cis. This folding of the chain forms the cup in which the Li ion is located. The co-ordination is completed by a MeCN molecule rendering a completely hydrophobic cage round the lithium. The complex differs from the K+-nonactin and K'-valinomycin complexes in several respects. K' occupies the centre of the complex, and is symmetrically surrounded by six or eight oxygen atoms, with K-0 distances ranging from 2.7 to 2.8A. Furthermore, the nonactin ring folds into a figure resembling the seams of a tennis ball and completely encases the K'. The valinomycin forms a thick doughnut-shaped ring round K'. The Li+-antamanide complex, however, has much less symmetry, only an approximate two-fold axis, and much bulkier side-groups. The Li' ion resides in a shallow cup, with all ligands from the ion to the antamanide moiety on one side, while the other side of the Li is strongly co-ordinated to a solvent molec~le."~ ,The o-nitrophenolatobis( 1,10-phenanthroline) alkali metal complexes are the principal products when excess 1,lO-phenanthroline is added to the reaction solutions of the alkali-metal o -nitrophenolate in ethanol. The. sodium complex, C,,H,,N,NaO,, and rubidium complex are both triclinic, space group P , with a = 10.436, 11.413; b = 10.062, 13.214; c = 14.867, 10.068 A; a = 96.99, 99.06; p = 104.02, 114.80; y = 119.12, 101.78'; d(obs) 1.37, 1.48; and d(ca1c) 1.364, 1.494 for 2 = 1, respectively. In the sodium complex, the cation is six-co-ordinate, interacting with the three propellor-like chelating ligands in pseudo-32 symmetry, and the structure is of monomeric units, as shown in Figure 8. Each phenanthroline molecule is chelated to the cation through two N atoms; for molecule (A), Na-N distances are 2.491 and 2.506A, but for molecule (B) the Na-N distances are more dissimilar, at 2.444 and 2.557 A. The o-nitrophenolate ion is co-ordinated through the phenolic oxygen and one of the nitro-group oxygen atoms at Na-0 I. L. Karle, J . Amer. Chem. SOC.,1974, 96, 4000
26
Inorganic Chemistry of the Main -group Elements
Figure 8 o-Nitrophenolatobis-( 1,lO-phenanthr0line)sodium: one monomer unit, shown with two neighbouring phenanthroline ligands (Reproduced from J.C.S. Dalton, 1973, 2347) distances of 2.281 and 2.421 A. The rubidium complex has a similar pseudo-three-fold symmetry of the chelating ligands but, with a larger co-ordination sphere, the cation also accepts co-ordination with a second 0nitrophenolate ion, which thus bridges cations about a centre of symmetry, as shown in Figure 9. In the rubidium complex, the corresponding dimensions about the cation are: Rb-N, 3.059 and 3.082A in phenanthroline molecule (A), and 3.045 and 3.016A in molecule (B); Rb-(phenolic 0) is 2.838 and Rb-(nitro-group 0) is 2.949A. The extra Rb-0 distance is 3.190 A, and it therefore represents a weaker interaction than the The structure of the potassium salt of a cyclo-octatetraene dianion has
Figure 9 Diagrammatic representation of the co-ordination in a dimer unit of o-nitrophenolatobis-(1, 10-phenanthr0line)rubidium (Reproduced from J.C.S. Dalton, 1974, 2347)
"' D.
L. Hughes, J.C.S. Dalton, 1973, 2347.
Elements of Group I
27
been determined. The yellow air-sensitive crystals of potassium diglymebis(l,3,5,7-tetramethylcyclo-octatetraene), [K{(MeOCH,CH,),0}]2[CsKMe4], crystallize in space group P?(C:), with a =9.757, b = 10.026, c = 8.793A, a =97.15, p = 112.35, and y = 109.95", and with d(calc)= 1.16 for Z = 1. As predicted by the Huckel theory, this 1 0 ~ electron system is aromatic, with eight-fold molecular symmetry, and average C-C bond lengths of 1.407A. The complex exists as a discrete ion trimer. The anion ring lies sandwiched between two complexed potassium cations, as shown in Figure 10. The opposite side of each potassium ion is
Figure 10 A perspective drawing of [K{(MeOCH2CH2)20}]2[CsH4Me4]. Hydrogen atoms are not shown. (Reproduced by permission from J. Amer. Chem. SOC., 1974,96, 1348) co-ordinated by the three ether oxygen atoms of diglyme at an average distance of 2.835A. All the K-C bond lengths are equal, and average 3.003A. This is slightly shorter than the average K-C distance of 3.16 %, observed in the related compound [K{(MeOCH,CH,)O}][Ce(C,H8),] reported last year (Vol. 2, p. 31), whereas the K-0 distance is slightly longer.l16 Solvates containing two and six molecules of diglyme have been detected from solubility measurements of rubidium gallium hydride, RbGaH,, in diglyme from -66 to 115 "C. Above 80 "C, only unsolvated salt exists.'" 116
S. Z. Goldberg, K. N. Raymond, C. A. Harmon, and D. H. Templeton, J. Amer. Chem. SOC., 1974, 96, 1348. T. N. DymovaandYu. M. Dergachev, Izuest. Akad. Nauk S.S.S.R., Ser. khim., 1973,2659.
28
Inorganic Chemistry of the Main -group Elements Alkali-metal salts can be precipitated from aqueous solution by complexing with racemic 2,3-di(p-aminophenyl)butane. The complexes contain cations co-ordinated by six amino-N atoms to give an infinite threedimensional polymeric structure. Strong cation-nitrogen bonding exists, but cation-anion interaction is weak.'" The crystal structure of NaCl(dpb) is hexagonal, space (dpb = p7p'-diamino-2,3-diphenylbutane, C16HZON2) group R%, with a = 21.172, c = 17.004 A, d(obs) = 1.178, d(ca1c) = 1.176 for Z = 6. The amine nitrogen atoms are hexaco-ordinated to the Na ions, with a bond length of 2.608 A.119Hexamethylphosphoramide solvates of alkali-metal salts have been prepared and characterized by elemental analysis, melting points, and i.r. spectra. The wavenumber of the P-0 stretch of L decreased by 15-25 cm-I upon co-ordination to the metal ions in the compounds LiXL [L = (Me,N),PO; X = C1, SCN, ClO,, NO,, or BF,], NaXL [X = I, SCN, or ClO,], LiX,2L [X = SCN or OAc], NaSCN,2L, and LiX74L [X = Br or C104].'20A further example of a salt-neutral molecule complex is provided by KIs(xanthotoxin)z,which is triclinic, space group P?, with a = 9 . 5 9 , b=11.09, c = 7 . 9 6 A 7 a=118.1, p = 8 6 . 7 , y=114.5", d(expt) = 2.11, and d(ca1c) = 2.11 for 2 = 1.lZ1In solution, 23Na n.m.r. spin-lattice relaxation-time measurements of aqueous Na' mixtures with cysteine, aspartic acid, and citric acid show that only a weak interaction of cysteine and aspartic acid with Na' exists, whereas a Na' complex is formed with the citrate ion.lZ2The electrostatic binding of Na' and K' by fulvic acid in aqueous solution has been measured with cation electrodes at 25 "C. The binding equilibria were studied by acid-base titrations, and distinct binding regions in the titration curves were The compounds LiC10,,3NH2OH, LiNO,,NH,OH, Mg(N0,)2,2NH,0H, and Ca(N03)2,2NHzOH have been prepared by the reaction of the anhydrous salts with hydroxylamine in organic solvents. Hydroxylamine is co-ordinated to the metal through the oxygen atom.124Potentiometric titrations of glucose and fructose with uni- and bi-valent cations show marked changes in potential at stoicheiometric hexose :salt ratios attributed to complex formation. For 1: 1 univalent cations the complexing ability was in the order Na'>K'>Li' for glucose but K+> Na' > Li' for fructose. For bivalent cations the corresponding orders were Sr2+> Mg2+> Ca2+> Ba2' and Ca" > Sr2' > Ba" > Mg2+.lZ5 Alkali-metal tetrahydroborates react with zinc chloride in ether, THF, or diglyme (DG) to give NaZn(BH,),,Et,O (9), NaZn(BH4),,2THF (lo), and RbZn(BH4),,2DG (11). The complexes (9) and (10) are soluble in all three
118
N. P. Marullo, J . F. Allen, G. T. Cochran, and R. A. Lloyd, Inorg. Chern., 1974, 13, 1 15. L. A. Duvall and D. P. Miller, Inorg. Chem., 1974,13,120. D. C. Luehrs and J . P. Kohut, J. Inorg. Nuclear Chem., 1974, 36, 1459. M . Kapon and F. H. Herbstcin, Nature, 1974, 249,439. T. L. James and J . H. Noggle, Btotnorg. Chem., 1973, 2, 69. D. S. Gamble, Canad. J . Chem., 1973, 51, 3217. Zh. G. Sakk and V. Ya. Rosolovskii, Zhur. neorg. Khirn., 1974, 19, 621. A. J. Dangre, J. Univ. Poona, Sci. Technol., 1973, No. 44, p. 217.
'lY
122
lZ4
Elements of Group I
29
solvents and (11) is soluble in diglyme. Generally, M,Zn(BH4)2+ndecomposed thermally to MBH, and Zn(BH4)2.126 The crystal structure of the complex bis[NN-ethylenebis(salicy1ideneiminato)copper(~~)]per chlorato-sodium-p -xylene, NaClO,[ Cu(salen)],p C6€&Me2,has been determined from three-dimensional X-ray data. Crystals are monoclinic, space group C2/2, with a = 24.44, b = 11.283, c = 14.766 A, p = 101.22", d(obs) = 1.56, d(ca1c) = 1.47 for 2 = 4. (Several compounds of this type were described in Vol. 2, p. 31). The structure contains discrete Na' ClO; ion pairs in which the cation is approximately octahedrally co-ordinated by two oxygen atoms of the perchlorate ion at 2.55 A and by four oxygen atoms from the two Cu(sa1en) complexes so that the sodium ion shares these oxygen atoms with a copper atom, Na-0 2.36, Cu-0 1.90 A. This is shown in Figure 11. The p-xylene molecule fills a
Figure 11 One Na'ClO; ion pair and the two chelating [NNethy lenebis(salicytideneirninato)]copper(11) molecules as seen along the crystallographic a-axis. The directions of the two-fold axis, b, and of the c-axis are indicated. (Reproduced from J.C.S. Dalton, 1974, 841) space in the loosely packed structure, and there are no atoms within 3.5 A of the The crystal and molecular structures of trisodium 6phosphogluconate dihydrate. Na3P0,C,H,o0,,2H,0, have been determined by X-ray analysis. The crystals are monoclinic, space group P 2 , , with
lZ7
V. I. Mikheeva, N. S. Kedrova, and N. N. Mal'tseva, Izvest. Akad. Nauk S.S.S.R., Ser. khim., 1974, 512. H. Milbum, M. R. Truter, and B. L. Vickery, J.C.S. Dalton, 1974, 841.
30
Inorganic Chemistry of the Main -group Elements
I"/ 2
I
Figure 12 The co-ordination polyhedra of the K' ions in potassium gluconate monohydrate. (a) Form A. (b) Form B. (Reproduced by permission from Acta Cryst., 1974, B30, 1421)
D-
a = 11.588, b = 5.876, c = 9.859 A, p = 97.57", and Z = 2. The structure is held together by an extensive hydrogen-bond network as well as sodium-ion co-ordination by oxygen from several 6-phosphogluconate ions.'*' Neutrondiffraction data have been used to refine the crystal structures of the A and B forms of potassium D-gluconate monohydrate, KC,H,,O,,H,O. These are space groups P2,2,2,, P2,; a = 8.220, 9.353; b = 17.840, 7.357; c = 6.717, 7.229 A; Z = 4 and 2 for the A and B forms, respectively, and p = 109.39" for the B form. The gluconate ion is straight-chained in A but bent in B. The cations are in voids between the puckered sheets of hydrogen-bonded anions and appear to have a secondary role in determining the structure. The cation co-ordination is shown in Figure 12. Interestingly, the cations 128
G. D. Smith, A . Fitzgerald, C . N. Caughlan, D. A . Kerr, and J . P. Ashmore, Acta Cryst.,1974, B30, 1760.
Elements of Group I
31
are as far removed as possible from the carboxylate oxygens, which are not included in the first cationic co-ordination shell. The eight nearest K-0 distances include 0-3, 0 - 4 twice, 0 - 6 , and two water (W) oxygens at distances between 2.61 and 3.24A. The fact that the charge on the gluconate ion (12) is, at least formally, located on the carboxylate group would not be deduced from observing this ~ t r u c t u r e . ~ ~ ~ OH OH H OH
I I
I l
I l
I 1
OOC-C-C-C-C-CHZOH H HOHH (12) D-gluconate ion
In lithium manganese(I1) ethylenediaminetetra-acetatepentahydrate, LizMn(edta),SH,O, the alkali-metal cation is tetrahedrally co-ordinated by oxygen atoms from two water molecules and two carbonyl groups. The average Li-0 distance is 1.94 A. The compound is ,orthorhombic, with a = 11.62, b = 9.04, c = 16.72 A, d(obs) = 1.67, and d(ca1c) = 1.69 for 2 = 4.130 The analogous compound, LiFe(edta),3H2O, has space group P2,/b, with a = 8.82, b = 17.80, c = 9.75 A, y = l l O ” , 2 = 4, and d(ca1c) = 1.92.13’ Co-ordination of the alkali-metal ion to oxygen atoms takes a very distorted trigonal-bipyramidal arrangement in the compound sodium nitrilotriacetatocopper(I1) monohydrate, N~CUN(CH~COO)~,H,O [or NaCu(nta),HzO]. By means of bonds to four different nta groups (Na-0 distances 2.2822.372 A) and a water molecule (Na-0 distance 2.288 A) the sodium ions help bind the structure together (Figure 13). The co-ordination by water of sodium rather than copper is not unusual. In other structures where CU(II), Na, and H,O are all present, such as sodium glycylglycylglycinocuprate(11) monohydrate and disodium glycylglycylglycinocuprate(I1) decahydrate, only the sodium ions are co-ordinated by water, even though the octahedron about the copper is incomplete. Similarly with LiCu(nta),3Hz0. Presumably, in each case chelation of the CU” ion neutralizes the ionic charge, so that subsequent stabilization of the structure is best achieved by coordination of HzO to alkali metal. The structure of NaCu(nta),H,O is orthorhombic, with a = 9.899, b = 12.565, and c = 7.548 A, and it belongs The crystal and molecular structures of to the space group P212,21.’32 guanosine 3’,5’-cyclic monophosphate sodium tetrahydrate, C,oH,,N,O,PNa,4Hz0, have been determined by single-crystal X-ray diffractometry. The crystals are orthorhombic, space group P2,2,2,, with a = 18.664, N. C. Panagiotopoulos, G. A. Jeffrey, S. J. La Placa, and W. C. Hamilton, Acta Cryst., 1974,
’” 13’
13’
B30, 1421. N. N. Anan’eva, T. N. Polynova, and M. A. Porai-Koshits, Zhur. strukt. Khim., 1974,15,261. N. V. Novozhilova, T. N. Polynova, M. A. Porai-Koshits, N. I. Pechurova, L. I. Martynenko, and Ali Khadi, Zhur. strukt. Khim., 1973, 14, 745. S. H. Shitlow, Inorg. Chem., 1973, 12, 2286.
32
Inorganic Chemistry of the Main -group Elements
Figure 13 A perspective view of the packing in NaCu(nta),H,O. The view, looking down the b-axis, selectively shows the basic nta structure, the metal atoms to which it bonds, and complete Cu and Na co -ordinations. (Reproduced by permission from Inorg. Chem., 1973, 12, 2286)
b = 7.384, c = 12.706 A, d(obs) = 1.66, and d(ca1c) = 1.665 for 2 = 4, assuming one Na' ion and four H 2 0 molecules per nucleotide. The bond distances and angles in the ribose ring show significant differences from those of the common nucleotides. The phosphate ring is locked into the chair position. The crystal packing consists of alternating layers of stacked nucleotides, with the interstitial holes filled by sodium-water distorted octahedra. The Na' ion is co-ordinated to six water molecules at distances from 2.32 to 2.68 A, thus barring them from direct contact with the anionic phosphate oxygens (Figure 14). Adjacent octahedra share edges to generate an infinite water hole impregnated with sodium ions, which are 3.77 A apart. The water molecules (W) around the Na' ion are in turn linked to the
Elements of Group I
33
Figure 14 The water-to-sodium bond distances and the water-to-nucleotide hydrogen- bond distances in guanosine 3',5'-cyclic monophosphate sodium tetrahydrate. (Reproduced by permission from Acta Cryst., 1974, B30, 1233) ribose 2'-hydroxy-group, the base N-7, 0 - 6 , and N-2 atoms, and the phosphate oxygen 0-7 by hydrogen The crystal structure of Na4H,Mo,PzOz,(H,0)lo has been determined from three-dimensional X-ray diffraction data. The compound is monoclinic, space group P2,/n, with a = 26.388, b = 13.661, c = 8.041 A, and /3 = 91.37", 2 = 4.The structure is built up from [HzMo,P,0,3]4- anions, Na' cations, and H,O molecules. The complex anions are linked together by direct sodium bridges (0-Na-0) in the y - and z-directions, forming infinite layers parallel to the yz-plane. These layers are held together by 0-Na-H,O-Na-0 linkages. Each Na' ion is surrounded by six oxygen atoms (water and ligand-group oxygens) to form an octahedron which is distorted. 134 Trisodium gallium trimetaphosphimate dodecahydrate, Na,Ga12Hz0, also consists of complex anions Ga[(PO,NH,)]:-, Na' (P306N3H3)2, cations, and water molecules. The crystals are triclinic, space group P i , with a = 8.729, b = 9.902, c = 8.716 A, a = 97.84", /3 = 87.88", y = 93.45", and 2 = 2. The trimetaphosphimate groups are terdentate ligands joined to Ga atoms through 0 atoms. Between Na3(H20),2fragments and complex anions there are Na-0 A. K. Chwang and M. Sundaralingam, Acta Cryst., 1974, B30, 1233. B. Herman, Acta Chern. Scand., 1973, 27, 3335. 135 V. I. Sokol, M. A. Porai-Koshits, L. A. Butman, I. A. Rozanov, and V. R. Berdnikov, Izuest. Akad. Nauk S.S.S.R., Ser. khim., 1974, 485, 133
134
34
Inorganic Chemistry of the Main-group Elements
Alkali-metal and ammonium salts of halogenoacetic acids have been studied. In aqueous lithium chloroacetate-chloroacetic acid mixtures, the unstable compound 2CH,ClC0,Li,CH2C1C0,H is formed. From CHC1,C0,Li-CHCl,CO,H-H,O mixtures the two compounds 2CHCl,CO,Li,CHC12C02H,H20and CHC1,CO,Li,2CHC1,CO2H are formed. In CCl,CO,LiCCl,CO,H-H,O mixtures, the phase 2CC1,CO2Li,CC1,CO,H is produced. 136 The phase diagrams of the ternary systems of the three chloroacetic acids with their sodium salts have also been investigated. With CH,ClCO; no definable compound was isolated, but a stable monohydrate and unstable dihydrate of CHCl,CO,Na were formed. With CCl,CO;, the trihydrate of CCl,CO,Na, decomposing easily into the dihydrate, and the salt CCl,CO,Na,2CC1,C02H were isolated. '37 The structure of potassium hydrogen bis(dichloroacetate), KH(CHCl,CO,),, is monoclinic, space group P2,/c, with lattice parameters a = 6.246, b = 23.187, c = 9.325 A, p = 106.73", d(obs) = 1.90, and d(ca1c) = 1.935 for Z = 4.138Rubidium hydrogen trichloroacetate, RbH(CCl,CO,),, has space group I2/c, with a = 9.395, b = 6.410, c = 10.293 A,/3 = 93.70", cf(obs) = 1.23, and d(ca1c) = 2.28 for z =4.13' The 7Li n.m.r. spectrum of lithium acetate dihydrate, LiCH3C0,,3H,0, indicates a tetrahedral configuration round the lithium ion, confirming recent 'H n.m.r. and X-ray results.140The compounds MHO(CH,CO,), (M = Na c r K) are both monoclinic, with space group P2,/c, four units in the cell, and cz=6.990, 7.107; b=9.610, 10.451; c=8.434, 8.558A; p = 103.34, 101.44" for the sodium and potassium compounds, respectively. These metal hydrogen oxydiacetates contain infinite chains of oxydiacetate anions linked by a short hydrogen-bond. The chains are cross-linked by the alkali-metal cations.141 These features are common to the rubidium analogue but this is tetragonal, space group I42d, with a = 8.481, c = 18.099 A, and 2 = 8.'", Infinite chains of hydrogen malonate residues are also linked by short unsymmetrical hydrogen-bonds in sodium hydrogen malonate, which is monoclinic, space group P2,/c, with a = 6.664, 6 = 7.522, c = 9.337 A, P = 100.69", d(obs) = 1.80, and d(ca1c) = 1.78 for 2 = 4.'"' Compounds of sodium with P-diketones HL (HL = 2,4-acetoacetoxylide, acetoacet-o-anisidide, benzoylacetanilide, or benzoyl-rn-nitroacetanilide) have been prepared in dry ether-ethanol solvent. The compounds NaL were identified by analysis and U.V.and i.r. The thermal decomposition of sodium acetylacetonate and its dihydrate, NaL and NaL,2H,O (HL = acetylacetone), between 25 and 1000 "C proceeds in two J . Pokorny, 2. Chem., 1973, 13, 303. J . Pokorny, Z. Chem., 1973, 13, 439. '31 I . Leban, Cryst. Struct. Comm., 1974, 3, 245. 139 L. Golic and P. Lazarini, Cryst. Struct. Cornrn., 1974, 3, 411. 14(1 S. V. Bhat, A . C. Padmanabhan, and R. Srinivasan, Acta Cryst., 1974, B30, 846. 141 J. Albertsson, I. Grenthe, and H. Herbertsson, Acta Cryst., 1973, B29, 1855. lilZ J. Albertsson, I. Grenthe, and H. Herbertsson, Acta Cryst., 1973, B29, 2839. S. N. Rao and R. Parthasarathy, J.C.S. Perkin 11, 1974, 683. 1 4 4 A . D. Taneja, J. Inorg. Nuclear Chem., 1973, 35, 3617.
13'
13'
Elements of Group I 35 stages. Thermogravimetric analysis shows that NaL yields Na,CO, at ca. 400°C, and this is superseded by NazO at ca. 700°C. NaL,2H20 also lost the expected amount of water in two well-defined Preliminary X-ray diffraction data for caesium and potassium dipicrylaminates indicate triclinic structure, space group P1 or P i , with a=8.77, b = 11.50, c = 8.77 A, a = 88" 30', f3 = 104" 45', y = 91" 20', d(exp) = 2.14, d(ca1c) = 2.23 for Z = 2 for the caesium salt, and monoclinic, space group P2, Pm, or P2/m, with a = 11.05, b = 12.30, c = 13.02 A, y = 93" 20', d(expt) = 1.75, d(ca1c) = 1.82 for Z = 4 for the potassium ~ a 1 t . Disodium l~~ maleate monohydrate, Na2C4H204,H,0,crystallizes from DMSO-water mixtures in the form of thick plates of space group C2/c, with a=20.979, b = 10.004, c =6.369& p = 100.15". The maleate dianions are held together in an edge-to-edge manner by Na' and H 2 0 bridges. The Na+ ions reside in distorted square-pyramidal sites formed by five oxygen atoms at an average Na-0 distance of 2.402 A.147 Crystals of sodium 7,7,8,8-tetracyanoquinodimethanide, Na(tcnq), Na(C12H4N,),are triclinic, with space group C i and lattice constants a = 6.993, b = 23.707, c = 12.469 A, a = 90.14", p = 98.58", y=90.76", and Z = 8 . The tcnq ions form a columnar structure along the a-axis with alternating interplanar distances of 3.21 and 3.49 A. Accordingly, tcnq dimers are recognized in the structure. The Na' is surrounded octahedrally by six nitrogen atoms of different tcnq ions at distances between 2.419 and 2.565 A, compared with cubic 8-co-ordination of the cation by nitrogen in Rb(tcnq) and K(tcnq), although the structures of the potassium and sodium salts are most closely ~e1ated.l~'In Rb(tcnq) (form 11) the interplanar spacing in the dimer is much wider than in the other salts. Moreover, Rb(tcnq) is triclinic, space group P i , with a = 9.914, b = 7.196, c = 3.390 A, a = 92.70°, p = 86.22", y = 97.73", and d(ca1c) = 1.757. 149
6 Alkali-metal Oxides Ab initio quantum-mechanical calculations have been made for the two lowest electronic states of the Li02 molecule. For isosceles triangular configurations, the 'A2 state is the ground state, with equilibrium geometry r(Li0) = 1.82 A and O(0-Li-0) = 44.5". The 2B2state is predicted to lie 14 kcal mol-' higher, with r(Li0) = 1.76 A and O(0-Li-0) = 46.5". For C,, symmetry the 'lJ state bond distances were predicted, r(Li-0)= 1.62 A and r ( 0 - 0 ) = 1.35 A. There appears to be little or no barrier The decomposition of anhydrous lithium between the C2uand C,, 14'
146
147
1 4 '
' 4 1
E. Boschmann and W. A. Althaus, Proc. Indiana Acad. Sci., 1973, 82, 156. V. P. Chalyi, G. N. Novitskaya, Yu. P. Krasan, L. L. Shevchenko, and A. T. Pilipenko, Zhur. strukt. Khim., 1974, 15, 159. M. N. G. James and G. J. B. Williams, Acta Cryst., 1974, B30, 1257. M. Konno and V. Saito, Acta Cryst., 1974, B30, 1294. I. Shirotani and H. Kobayashi, Bull. Chem. SOC. Japan, 1973, 46, 2595. S. V. O'Neil, H. F. Schaefer, and C. F. Bender, J. Chem. Phys., 1973, 59, 3608.
36
Inorganic Chemistry of the Main -group Elements
hydroxide under a pressure of lopsTorr at 360 "C for 48 h, and at 640730 "C for periods s 1.3 h, in Ni, Mo, Nb, or Ta containers is reported to produce a residue of chemical composition Li30,. This is considered a single compound belonging to the orthorhombic system, with a = 10.84, b = 12.84, and c = 10.36 A, and it was also formed on evaporating excess lithium metal from a solution of oxygen in liquid lithium at S730"C for 1.5 h at ca. Torr. Under these conditions the monoxide Li,O rather than Li,O, had previously been assumed to be the residue.lsl The Li,ONa,O binary system has been investigated and exhibits the following features (compositions in YO Li,0):152eutectic, 770 "C; P-Na20 (ss) (10%)+ Li,O (ss) (85%) =liquid (24%) eutectoid, 675 "C; a-Na,O (ss) (5%)+Li,O (ss) (90%) = P-Na20 (ss) (10%) peritectic, 980 "C; P-Na20 (ss) = y-NazO (ss) + liquid ( 1O0/o) or metatectic, 960 "C; P-Na20 (ss) +liquid (10%) = yNa,O (ss). The e.s.r. spectra of the molecules NaO,, KO,, RbO,, and CsO,, isolated in rare-gas matrices, are consistent with an ionic M'O; model of isosceles symmetry, in accord with recent vibrational spectra. The e.s.r. spectrum for CsO, also shows evidence for an inversion of the uppermost occupied molecular orbital which can be attributed to a slight covalent mixing of the oxygen valence orbitals with the inner-shell p-orbitals of the meta1.lS3The Raman spectrum of clear single crystals of sodium superoxide, NaO,, shows a molecular mode in addition to the usual vibrational modes. The Raman line at 1156 cm-' at 300 K corresponds to the usually found frequency of the 0; ion, and confirms that NaO, is ionic. Structural phase transitions at 230 and 201 K agree with previous findings by specific-heat and X-ray analy~is."~ The solubility of potassium superoxide KO, in liquid ammonia has been measured from -75 to -40°C. Equilibrium in the system was slow, taking 3 . 5 4 h. At -40 "C, 0.024*0.003 g of 92% pure KO, dissolves in 100 cm3 of ammonia.155On heating mixtures of KO, with lithium perchlorate, cation exchange occurs between the components, accompanied by liberation of oxygen. At 250-300°C the mixture melts with evolution of oxygen. At 360-500 "C, perchlorate is also decomposed. These melts are recommended for oxygen preparation."" The reactions of potassium peroxide K,O, with halogens in carbon tetrachloride and DMSO have been studied. The K,O, was derived from the thermal decomposition of KO,. In CCl,, K,O, did not react, but in DMSO, bromine and iodine are converted into KBr and KI, respectively. S. Stecura, J. Less-Common Metals, 1973, 33, 219. G. Papin, Compt. rend., 1973, 277, C , 677. 1 5 3 D. M. Lindsay, D. R. Herschback, and A. L. Kwiram, Chem. Phys. Letters, 1974, 25, 175. l S 4 M. Boesch, W. Kaenzig, and E. F. Steigmeier, Phys. Kondens. Mater., 1973, 16, 107. l S 5 A. E. Kharakoz, E. Romashov, T. B. Durnyakova, S. V. Bleshinskii, 1. I. Vol'nov, and S. A. Tokareva, Izuest. Akad. Nauk Kirg. S.S.R., 1974, 51. V. Brunere, A. Salta, and I. I. Vol'nov, Latu. P.S.R. Zinat. Akad. Vestis, Kim. Ser., 1973, 397. 15'
lS2
Elements of Group I 37 Chlorine did not react, and this was attributed to the formation of more stable adducts between the halogen and DMS0.lS7 Matrix reactions of the alkali-metal atoms with ozone have been followed by i.r. spectroscopy. At 15 K, deposition of alkali-metal atoms and ozone at high dilution in argon produced very intense bands at 800cm-' and weak bands at ca. 600 cm-', which showed appropriate isotopic shifts for assignment to v, and v 2 of the 0; ion. There was evidence for a symmetrically bound cation to O,, with C,,, symmetry. The symmetric interionic stretching mode was observed at 281 cm-l for Cs'O;. The reaction between these constituents produced the CsO fundamental at 322 cm-' and Cs,O at 457 cm-l. Simultaneous photolysis using a mercury arc was required to yield the LiO absorption at 752 cm-' from the Li-0,-argon-matrix r e a c t i ~ n . " ~ E.s.r. spectra of nitrogen-matrix-isolated caesium monoxide and 2 ground state. This state rubidium monoxide molecules confirmed the ' results from mixing of the filled (n - l)p alkali-metal orbitals with the 2p oxygen orbitals, analogous to the innerrshell bonding in the isoelectronic XeF and KrF X-Ray diffraction reveals that rubidium and caesium superoxides undergo a phase transition from the tetragonal (I4/mmm) to the cubic (Fm3m) structure on heating at 130-150 and 130-200 "C, respectively. Analogous to the 0; ion in the P-phase of KO, or NaO,, the 0; ion in RbO, and CsO, either does not have a preferred orientation or is rotating. The f.c.c. crystal of RbO, has a = 6.35 8, at 150 "C, and that of CsO, has a = 6.62 A at 200 "C.16' The thermal decomposition of CsO, has been investigated from 320 to 440 "C, and covered the composition range cs202.06~s203.96.There is no formation of solid solution or sesquioxide over this composition range. The reaction path was deduced to be:
2cs02 (s) = cszo2 (s) + 0
2
(g)
For caesium peroxide, over the composition range 320-500 "C, the reaction path is:161
at
2cs20, (s) = 2 c s 2 0 (s) + 0, The standard free energy of formation, AGO, of caesium monoxide has been
calculated from experimental results as -308.42 f 1.18 kcal mol-'. To permit practical thermodynamic calculations to be made at higher temperatures, experimentally determined heat capacities at 5-350 K have been extrapolated to 763 K, the m.p. of C S , ~ ,and a table of extrapolated thermodynamic functions, including AGO, is now available up to 763 K.16' lS7
lS8 159 160 16' 162
Dz. Pelca, V. Brunere, and J. Sauka, Latu. P.S.R. Zinat. Akad. Vestis, Kim. Ser., 1973, 390. R. C. Spiker, jun., and L. Andrews, J. Chem. Phys., 1973, 59, 1851. D. M. Lindsay, D . R. Herschback, and A . L. Kwiram, J. Chem. Phys., 1974, 60, 315. V. Ya. Dadarev, A. B. Tsentsiper, and M. S. Dobrolyubova, Kristallografiya, 1973, 18, 759. S. P. Berardinelli and D . L. Draus, Inorg. Chem., 1974, 13, 189. H. E. Flotow and D. W. Osborne, J. Chem. Thermodynamics, 1974, 6, 135.
38
Inorganic Chemistry of the Main -group Elements
The standard enthalpy of formation, AH", of caesium monoxide is -82.69 f 0.28 kcal mol-'. This value was derived from a solution-calorimetry study of high-purity Cs,O dissolving in excess water to form CsOH (aq).163
7 Alkali-metal Halides The purification of alkali-metal halides has been re~iewed.'~" Interaction potentials of many ion pairs have been calculated assuming that the electron density of the combined system is equal to the sum of the two separate ionic electron densities. The Coulomb-energy contribution to the interaction was calculated directly from the charge distribution of the nuclei and the assumed electron density. The non-Coulombic part of the interaction energy was calculated from the electron density, using the electron-gas energy expression in terms of the local density. The ions treated are those of Li, Na, K, Rb, Be, Mg, and Ca and F, C1, and Br. The predicted molecular bond energies, bond lengths, and vibration frequencies agree well with existing experimental data when the calculated ion-ion interaction potentials are applied to the theory of these halide Precise values have been obtained for the outer electronic bands of the alkali-metal fluorides by using 40.81 eV U.V. photoelectron spectroscopy. An approximate difference of 1.1eV between experimental and Born-model, binding energies is attributed to polarization eff ects.166Similarly for the alkali-metal ch10rides.l~~ (See also Vol. 2, p. 39.) The He I photoelectron spectra of the gaseous molecules of CsF, LiBr, MCl, MBr, and MI (M = Na, K, Rb, or Cs) have been obtained by using a high-temperature spectrometer equipped with an internally located laser-beam-heated sample oven. The spectral bands were assigned MO origins by use of MO calculations, spin-orbital splitting considerations, band-intensity relations, polymer-formation tendencies, and mass-spectrometric data.16*The He I photoelectron spectra of the caesium halides have been measured. They exhibit two well-separated sets of peaks; one derived from orbitals formed from halogen p-orbitals and the other from Cs p-orbitals. Each set of bands was analysed by including spin-orbit interaction within the degenerate ll states and subsequently and C(l/z)states. This analysis is a prototype for all between the IIcl/z) alkali-metal halides and has been used in conjunction with ab initio calculations to construct potential-energy curves for LiC1, LiBr, LiI, and KF. These cases suffice to characterize the variations in the photoelectron 163 164
166
167
J. L. Settle, G. K. Johnson, and W. N. Hubbard, J. Chem. Thermodynamics, 1974, 6, 263. F. Rosenberger, Ultrapurify, 1972, p. 3, ed. Z . Morris. Y. S. Kim and R. G. Gordon, J. Chem. Phys., 1974, 60, 4332. R. T. Poole, J. Liesegang, R. C. G. Leckey, and J. G. Jenkin, Chem. Phys. Letters, 1973, 23, 194. R. T. Poole, J. G. Jenkin, R. C. G. Leckey, and J. Liesegang, Chem. Phys. Letters, 1973, 22, 101. T. D. Goodman, J. D. Allen, jun., L. C . Cusachs, and G. K. Schweitzer, J. Electron Spectroscopy Related Phenomena, 1974, 3, 289.
Elements of Group I
39
spectra and mass spectra for all the alkali-metal halides.'"' High-resolution X-ray photoemissions of LiF, NaF, NaC1, NaBr, NaI, KF, KCl, KBr, and KI are reported. The valence-band spectra are compared with previous spectra of the isoelectronic series Group IV, 111-V, and 11-VI crystals. Features of the spectra evolve systematically in proceeding from the Group IV elements to the I-VII crystals. An analysis of this trend leads to the interpretation of the structure of the outermost halogen p band in the less ionic cases as being due to band effects rather than to spin-orbit splitting."" Infrared absorption spectra have been measured for NaF and KF isolated in solid argon. The fundamental modes of these species and the B3",BZu, and B1, modes of (NaF), and (KF), are assigned assuming a planar rhomboid structure of D,, symmetry for the dimers.171Surface ionization of lithium and its halides has been studied by a double-filament technique. At relatively high temperatures the temperature dependence of the lithium surface ionization current from all molecules studied was identical with that from lithium. Incomplete dissociation of LiCl can account for Li ionization threshold temperatures well above that for surface ionization of Li atoms. Dissociation energies of 4.8k0.1 eV for LiCl(g) and 4.3 *0.1 eV for LiBr(g) were The equilibrium ionic forms in salt vapours have been studied. The concentration of M' and X- ions in the saturated vapours of MX (M = Na or K, X = halogen) at 850 "C is 107-1010 ions cm-3 and the ions ~ m - so ~ ,that the concentration of M,X+ and M,X- ions is 10'-lo" vapours exhibit measurable electric conductivity. The equilibrium constants for the gaseous reactions are as follows: KI = K++I-
I-= I + e 21 = I, K'+e-=K KI + I- = KI, KI + K+= K21+
lo-'" atm 3.386 x lo-' atm 3.272 X
43.18 atm-'
lo1' atm-' 1 . 9 0 6 ~lo3 atm-' 2.041 x lo' atm-' 2.196 x
and are calculated from existing thermodynamic functions for KI, K', I-, K21i, and KI;. The equilibrium constants, enthalpy, and entropy for the' reactions : MX = M + +Xand
3MX = M2X++ MX;
are also calculated for lithium, sodium, potassium, and caesium halides. The equilibrium constants increase in the order F < C l < B r < I for salts with a J. Berkowitz, J. L. Dehmer, and T. E. H. Walker, J. Chem. Phys., 1973, 59, 3645. S. P. Kowalczyk, F. R. McFeely, L. Ley, R. A. Pollak, and D . A. Shirley, Phys. Reu. (B), 1974, 9, 3573. 17' Z.K.Ismail, R. H. Hauge, and J. L. Margrave, J. Inorg. Nuclear Chem., 1973, 35, 3201. "* E.N. Sloth, M. H. Studier, and P. G. Wahlbeck, J. Phys. Chem., 1974, 78, 820.
169 170
Table 5 Complex halides that have been investigated Compound
Ref.
AZBMF6 Lattice constants for forty compounds (A, B = Li, Na, K, Rb, Cs, or TI; given M = Al, Ga, V, Cr, Fe, or Co)
180
M3A1F6 (M = Li or Na)
Direct fluorination of M,A1H6
181
LiAIF4, LizAIF5
Partial pressures in LiF-AIF, mixtures of complexes and of LiF and LizF. For LizAIH5= LiA1H4+ LiF at 109 K, AH = 58.7 kcal mol-' and AS = 30.4 e.u.
182
183
CsAIBr,, RbCsAI,Br, LiGaF,, (LiGaF4)z, Li2GaF5
Partial pressures above LiF-GaF, mixtures of complexes and of LiF, Li2F2,and Li3F3 at 869 K. Enthalpies/kcal mol-' of sublimation, AHs, and dissociation, AH:y8, are, respectively: LiGaF, = LiF + GaF,
62.1, 61.3
LizGaF5= LiF+ LiGaF, (LiGaF,), = 2LiGaF4
55.5, 60.9 46.0, -
184
MGaBr,, MGazBr7, (M= Rb or Cs)
Incongruent m.p.s/"C: RbGaBr,, 2 5 2 ; CsGaBr,, 320; RbGa2Br7, 125; CsGazBr7, 170.
185
CsSn"Ha1,
CsSnCI,, CsSnBrzC1, CsSnBr,, CsSnBrJ, CsSnBrIz, and CsSnI, all have cubic perovskite structure. Halogen n.q.r. spectra presented.
186
Unit-cell dimensions/A for Fm 3m crystals, and Sn-C1 bond lengths/A are 9.9818, 2.411; 10.0442, 2.421; 10.0961, 2.423; 10.3552, 2.423; 12.835, 2.402 for M = K , N K , Rb, Cs, and Me,N, respectively. The n.q.r. frequencies steadily increase with increasing cation size. Raman spectra. Tetrahedrally co-ordinated C1 by Sb converted into octahedral with increasing size and numbers of alkalimetal cation.
187
3KC1,2SbCI3 and RbCI,SbCI,
188
Orthorhombic, space group Pmcn, a = 7.630, b = 13.079, c = 18.663 A, Z = 4. Close packing of Cs and C1 atoms with Sb in octahedral holes.
189
= 7.644,
189
Cs,Bi,Cly
Orthorhombic, space group Pmcn, a b = 13.277, c = 6.84 A, Z = 4.
MzSbBrb
So Values are estimated as 118.3 and
190
109.0 cal K-' mol-' for M = Rb and Cs, respectively. 3CsBr,2BiBr3 and 3CsBr,BiBr3
3RbCI,BiC13, 7RbC1,3BiC13, and 3RbC1,2BiC13
Thermal stability up to 750 "C. Compounds decompose, giving BiBr, and CsBr. 3CsBr,2BiBr3 passes through 3CsBr,BiBr, stage. Thermal stability. 7RbC1,3BiC13 d. 140 "C to 3RbCI,BiC13 and 3RbC1,2BiC13. Subsequently 3RbC1,2BiCI3 gives BiCI? and RbCI.
191
192
Elements of Group I
41
common anion.173Potential-energy-surface calculations for the M2X' ions show that the ion has substantial binding energy (ca. 1.5-2 eV with respect to M'+MX), where M and X are alkali metal and halogen, respectively. The most stable configuration varies from linear for (heavy M, light X) to strongly bent for (light M, heavy X).*" The hydrolysis of the halides of lithium, sodium, beryllium, and magnesium, amongst others, has been rationalized in terms of Lewis acid-base properties. 175 The crystal structures of the compounds KICl, and KIC1,,H20 have been determined from X-ray diffraction data. Potassium dichloroiodide crystallized in space group P2,/c, with a = 8.507, b = 10.907, c = 12.126 A, p = 107.82", and Z = 8. The monohydrate crystallized in space group P2,/m, with a = 8.022, b = 9.611, c = 4.354 A, p = 97.03", and Z = 2. In the anhydrous compound the two independent ICl; ions are nearly linear and symmetric, with average I-Cl bond lengths of 2.55 A. The ICl; ion is also linear in the hydrate, with the same I-Cl bond 1e11gth.l'~ Crystals of KIBr,,H,O are orthorhombic, space group Pnnm, with a = 12.183, b = 13.046, c = 4.390 A, and Z = 4. The two independent IBr; ions are linear and symmetrical, both with I-Br bond The crystal structure of caesium dichloroiodide has lengths of 2.71 been refined as trigonal, space group Rgm, with a = 5.469 A, a = 70.67", and Z = 1. The I-CI bond length is 2.548 The hygroscopicity of the powdered salts NaCl, KBr, and KI prepared by recrystallization from ethanol has been studied by comparing the surface conductivity of the salts with their water adsorption isotherms. The surface conductivity-relative pressure relationships showed four parts. Adsorbed H 2 0 molecules forming 2 layers dissolved salt particles and began to form hydrated ions possessing considerable mobility. For NaCl, KBr, and KI, the vapour pressures at which the adsorbed water molecules started to form the hydrated ions at 30°C were 33, 36, and 27% relative humidity, respectively. The ions were hydrated with 10, 11, and 9 molecules of water, re~pectively.'~~ A very large number of complex halides containing alkali-metal ions have been investigated. Many of these are covered in the section on Molten Halides. The majority of the remainder are presented in Table 5.180-1y2 173 174
175 176
177 17'
' 7 1
'* lE3
N. L. Yarym-Agaev and V. G. Matvienko, Teplofiz. Vys. Temp., 1973, 11, 757. S. M. Lin, J. G. Wharton, and R. Grice, Mol. Phys., 1973, 26, 317. P. W. Wiggans, Educ. in Chern., 1973,10, 178. S. Soled and G. B. Carpenter, Acta Cryst., 1973, B29, 2104. S. Soled and G. B. Carpenter, Acta Cryst., 1973, B29, 2556. F. Van Boihuis and P. A . Tucker, Acta Cryst., 1973, B29, 2613. T. Kanazawa, M. Chikazawa, M. Kaiho, and T. Fujimaki, Nippon Kagaku Kaishi, 1973, 1669. D. Babel, R. Haegele, G. Pausewang, and F. Wall, Materials Res. Bull., 1973, 8, 1371. S. D. Arthur, R. A. Jacob, and R. J. Lagow, J. lnorg. Nuclear Chem., 1973, 35, 3435. E. N. Kolosov, V. B. Shol'ts, V. A . Davydov, and L. N. Sidorov, Vestnik. Moskou. Uniu., Khim., 1973, 14, 315. V. I. Mikheeva, S. M. Arkhipov, and A. E. Pruntsev, Izuest. Akad. Nauk S.S.S.R., Ser. khim., 1973, 2810.
42
Inorganic Chemistry of the Main-group Elements
8 Lithium Compounds The chemistry of the typical elements has been re~iewed.”~A second review covers the alkali metals and alkaline-earth elements 0n1y.I’~ Tables of electronic wavefunctions have been compiled for the diatomic hydrides AH, where A denotes the elements Li through F, and Na through Cl.”’ X-Ray diffraction patterns at high pressure show that LiH retains the low-pressure NaCl structure up to 12.0 GPa (120 kbar).”‘ The preparation of the first stable complex metal hydride of copper, lithium dihydrocuprate(I), is reported from the reduction of LiCuMe, by lithium aluminium hydride in ether at low temperatures. The solid compound, LiCuH,, is solvated by ether and stable under ambient conditions for several The reduction of inorganic compounds with alkali-metal borohydrides has been reviewed together with the electrochemical properties of borohydrides in s ~ l u t i o n . ”The ~ crystal structure of lithium hydrazinium fluoroberyllate, Li(N,H,)BeF,, is orthorhombic, space group Pna2,, with a = 9.811, b = 8.880, c = 5.139 A, and 2 = 4. The Li and Be atoms are at the centres of corner-sharing F tetrahedra. The hydrazinium ions lie in channels in the resultant framework. Average Li-F and Be-F bond distances are 1.853 and 1.546,8,, respectively.”’ The Li,O-B,O, phase diagram has been reported. The monoclinic (aand p-) and the tetragonal y-forms of LiB02, and the two forms of Li6B409,have been studied by X-ray crystallography. The tetragonal (y -) form was formed by heating the monoclinic (a-)form at 350 “C for 30 h; the y-LiBO, was stable to 580°C. The lattice constants of tetragonal y-LiBO, are a = 4.196, c = 6.51 1 A, space group I a 2 d . Monoclinic pLiBO, (metastable, m.p. 822 “C) was prepared from y-LiBO, at 580 “C by enantiotropic transformation. The compound Li6B409,previously prepared, lS4
N. A. Zhegul’skaya and L. N. Sidorov, Zhur. fiz. Khim., 1973, 47, 1622.
A. G . Dudareva, T. V. Fedorova, Yu. E. Bogatov, and P. I. Fedorov, Zhur. neorg. Khim., 1974, 19, 1607. D . E. Scaife, P. F. Weller, and W. G. Fisher, J. Solid State Chem., 1974, 9, 308. T. B. Brill, R. C. Gearhart, and W. A. Welsh, J . Magn. Resonance, 1974, 13, 27. lS8 K. 1. Petrov, V. V. Fomichev, G . V. Zimina, and V. E. Plyushchev, Khim. Khim. Tekhnol., Tr. Yubileinoi Konf., Posvyashch. 70-Letiyu Inst., ed. A. N. Bashkirov, (Mosk. Inst. Tonkoi Khim. Tekhnol.), 1970, (Publ. 1972), p. 349. 189 K. Kihara and T. Sudo, Acta Cryst., 1974, B30, 1088. S. H. Lee and C. A. Wulff, J. Chem. Thermodynamics, 1974, 6, 85. 191 V. D. Shcheglova, V. P. Gofman, S. B. Stepina, and V. E. Plyushchev, Izuest. sibirsk. Otdel. Akad. Nauk S . S . S . R . , Ser. khim. Nauk, 1973, 75. 192 V. D. Shcheglova, S. B. Stepina, V. E. Plyushchev, and A. S. Berger, Izuest. sibirsk. Otdel. Akad. Nauk S.S.S.R., Ser. khim. Nauk, 1973, 78. D. W. A. Sharp, M. G. H. Wallbridge, and J. H. Holloway, Annual Reports ( A ) , 1973, 69, 175. 194 M. F. Steffel, Ann. Reports Inorg. Gen. Synth., 1973, 1, 1. 1 9 5 P. E. Cade and W. Huo, Atomic Data Nuclear Data Tables, 1973, 12, 415. 196 B. Olinger and P. M. Halleck, Appl. Phvs. Letters, 1974, 24, 536. I y 7 E. C. Ashby, T. F. Korenowski, and R . D . Schwartz, J.C.S. Chern. Cornm., 1974, 157. J . Hanzlik, Chem. listy, 1973. 67, 1239. 19’ M. R. Anderson, I . D. Brown, and S. Vilmino, Actu Cryst.. 1973. B29, 2625. lS5
lS6
43 is dimorphic. At 650 "C, p -Li6B,0,Sy-Li,B,09.200 Lithium peroxoborate monohydrate, LiBO,,H,O, decomposes under vacuum at 115-145 "C, but only half the oxygen and water are lost. The residue has the composition LiB0,.,,0.5Hz0, and complete loss of water occurs at 250-300 "C. The activation energy for the decomposition of the peroxoanion is 46 kcal mol-l. The suggested structure for LiBO,,H,O is as shown in (13)."' Lithium alu-
Elements of Group I
minoborate, Li,Al,(BO,),, is monoclinic, space group P1, with a = 6.13, b = 4.82, c = 8.23 A, p = 118", and d(ca1c) = 1.58 for 2 = 1. The structure is composed of infinite chains of [A1,(B03),]6- and layers of Li' tetrahedra.," The melting and dissociation of lithium carbonate have been studied by differential thermogravimetry (t.g.a.) and differential thermal analysis (d.t.a.). Thermal dissociation of Li2C0, to Li,O and CO, begins at 200°C. An endothermic effect with the maximum at 745 "C corresponds both to the melting and the thermal dissociation. The course of the process is strongly influenced by the ease with which CO, is released from the sample; the peaks at 745 "C on the t.g.a. and d.t.a. curves are only coincident when one works with thin layers of sample.2o3In other work the m.p. of Li,CO, is given as 733"C, and up to this temperature the structure of the solid is monoclinic. Sodium and potassium carbonates possess three crystal forms: ordered monoclinic
hexagonal (high temperature)
K,34y Na347g21.c disordered monoclinic
The data confirm previous conclusions that two regions of continuous solid solution exist between Na2C03and K,C03. There is also evidence that in the binary Li2C03-Na2C03,an intermediate compound LiNaCO, Polymorphism also exists in the Li,X04 (X = Si, Ge, or Te) compounds. All three phases are isostructural above 700-750 "C but undergo phase transformations on cooling. Only Li,GeO, and Li,TeO, are isostructural at lower 'O0 '01
' 0 2 ' 0 3
'04
C. Maraine-Giroux, R. Bouaziz, and G. Perez, Rev. Chirn. rnine'rale, 1972, 9, 779. M. S. Dobrolyubova and A . B. Tsentsiper, Izvest. Akad. Nauk S.S.S.R., Ser. khirn., 1974, 1218. G. K. Abdullaev and Kh. S. Mamedov, Kristallografiya, 1974, 19, 165. T. E. Machaladze, G. D. Chachanidze, and R. N. Pirtskhalava, Soobshch. Akad. Nauk Gruz. S.S.R., 1973, 71, 109. G. Papin, Compt. rend., 1973, 277, B, 691.
44
Inorganic Chemistry of the Main -group Elements
temperature^.^^^ The mixed alkali-metal tetragermanate LiNaGe409crystal~ , a = 15.90, b = 4.683, c = 9.322 A, and lizes in the space group P c ~ 2with 2 = 4. A substitution of Na by Li leads to an isomorphous series LiNa-+ LizGe409.zo6 Ge409-+ Lil,,N~.,Ge409 X-Ray photoelectron spectroscopy of the N( 1s) core-electron binding energies of azides containing the alkali metals indicates that the electronic structure of the Ng ion is largely unchanged from compound to compound, and the differing thermal stabilities cannot be explained on the basis of different electronic structure. The N(1s) spectrum consists of two peaks in the vicinity of 398.5-404.9 eV separated by ca. 4.4 eV, as shown in the upper part of Table 6. The peak for terminal N is slightly broader than that Table 6 N(1s) Binding energies for metal azides
B.E./eV h
B.E. DiferenceleV
r403.4 402.6 404.9 404.0 403.9 403.6 403.6 403.9
399.8 398.5 400.6 399.6 399.6 399.4 399.2 399.8
4.4 4.1 4.3 4.4 4.3 4.2 4.4 4.1
403.3 403.1 403.1 402.6 402.4
398.9 398.7 398.7 398.3 398.1
4.4 4.4 4.4 4.3 4.3
of the central N. The values for the pure alkali-metal azides in the lower part of the table have been reported previously, and are included for compari~on.~~' The i.r. spectra of LiN0, and KNO, ion pairs matrix-isolated in argon, glassy water, and glassy ammonia at 1 2 K have been measured and show a drastic reduction in the splitting of the v3(NO;) asymmetric stretch in the H,O and NH, matrices when compared to the argon base. This effect is attributed to solvation of the alkali-metal cation of the contact ion pairs, which occurs through the lone pairs of electrons on N or 0 of the matrix The d.t.a. of Li,P,09,3H,0 showed that dehydration occurred at 130-150 "C, and at higher temperatures infinite chains of tetrahedra were formed. The phosphate Li4P40,,,6H,0, prepared by addition of P,O, to aqueous Li,CO, at 0°C and evaporation at 8
;
}9
4 4
4 8 3
rikiA 1.589 2.544 1.58 2.563 3.02 1.85 1.58 2.563 3.02 1.85 1.58 2.563 3.02 1.85 1.58 2.56 3.02 1.85 3.02 1.85
used to study acid-base reactions in the Lux sense at 700°C. In potentiometric titrations using NaOH and Na'CO, the following equilibrium constants were
2po; + 0'- = p20;-
2.9 x 10'
p20:- + 0'- = 2po:PO; + 0'- = Po:-
2.5 x 10
co,+ 0'- = c0;PO;
+ C0:- = PO:- + COz
5 . 6 10' ~
2.5 0.5 X 10'
Measurements of the saturated vapour pressure of LiC1-CsC1 mixtures at 740-960 "C show that negative deviation from ideal behaviour exists in the system, and they reflect the formation of the complex [LiC1,]3-.304X-Ray diffraction data on the liquid salts LiF and BeF', and the compositions 4LiF,BeF2, 2LiF,BeF2, and LiF,BeF, at 875, 700, 745, 555, and 4OO0C, respectively, have been analysed to yield average nearest-neighbour distances and co-ordination numbers. The results are shown in Table 9. There 303
304
Yu. K. Delimarskii, V. I. Shapoval, 0. G. Tsiklouri, and V. A. Vasilenko, Ukrain. khim. Zhur. (Russ.Edn.), 1974, 40, 8. M. V. Smirnov, V. Ya. Kudyakov, and L. K. Khalturina, Tr. Ural. Politekh. Inst., 1973, 220, 18.
Inorganic Chemistry of the Main -group Elements
62
is a continuous increase of the mean distance between ions of opposite charge from 1.59 A in BeF, to 1.85 A in LiF. Similarly, the mean distance between neighbouring fluoride ions increases from 2.54 to 3.02A. The structure data are consistent with tetrahedral co-ordination throughout for Be in BeF:- units joined at each corner. With increasing LiF concentration the regular network becomes progressively distorted but the Be2' ions retain their immediate tetrahedral environment. The Li' ions occur in local and instantaneous environments that are grossly distorted from average tetrahedral c o - ~ r d i n a t i o n . The ~ ' ~ Knudsen effusion method has been used to vaporize KF-BeF, mixtures and the vapours have been analysed by mass spectrometry. The saturated vapour contains the ions K', K2F+,K,F;, BeFS, BeF', Be', Be,F:, KBeF:, and K,BeF:. The last two ions could only originate from complex molecules KBeF, and (KBeF3), in the vapour. At 1058 K, AG = 31.1 kcal mol-' for the reaction: KBeF, (g) = KF (g) + BeF, (g) and AH = 64.1, assuming the entropy of dissociation to be 31.2 cal K- ' m01-1.306 The vapour pressure above NaCl-BiCl, melts at 350-840 "C has Table 10 Phase diagrams that have been investigated Components
Compounds
Ref.
LiC1-NaCI-CsC1
LiCI,NaCI, LiC1,2NaCl, 309 LiC1,CsCl (d. 352 "C), LiC1,2CsCI (d. 382 "C) LiC1-RbC1-CsC1 LiC1,2CsCI 310 LiBr-NaBr-RbBr LiBr,RbBr, LiBr,NaBr, 311 LiBr,2NaBr LiBr-KBr-CaBr, KBr,CaBr, (m.p. 605 "C), 3CaBr,2LiBr (incongruent m.p. 418 "C) 312 KCI-SrCI, K,SrCI,, KSr,Cl, 313 KBr-SrBr, K,SrBr,, KSr,Br, 313 CsCl-CaC12 CsCaC1, 3 14 RbBr-Rb,CO, 2RbBr,Rb,CO, (m.p. 615 "C) 315 316 MBF, (M = Li, Na, K, Rb, or Cs) MBF,-MF 316 KCI-Li, AlF, 3 17 LiF-AlF, Li, AIF, 318 NaF-AlF, Na7A1F, 318 Li,AIF6-Cs,AIF, Cs,LiAIF,, orthorhombic, 3 19 a = 6.21, b = 10.72, c = 4 A, d(expt) = 4.04, and d(ca1c) = 4.14 for Z = 2 RbCI-TIC1 320 KX-RbX-PbX, KX, 2PbX2, 2KX,P bX, , 32 1 RbX,2PbX,, RbX,PbX,, (X = C1 or Br) 2RbX,PbX, 305 306
F. Vaslow and A. H. Narten, J. Chem. Phys., 1973, 59, 4949. A. N. Rvkov, Tu. M. Korenev, and A. V. Novoselova, Zhur. neorg. Khim., 1973, 18, 2493.
Elements of Group I
63 been measured by a static method employing a quartz null manometer. The composition of the vapour was determined by gravimetric analysis and by flame photometry. Both (NaCl), and NaBiC1, molecules were detected in the gas phase. At 350-65O0C, the enthalpy and entropy for the dissociation: NaBiCl,
= NaCl
+ BiCl,
were estimated to be 54.0 kcal mol-' and 38.0 e.u., re~pectively.~'~ The Raman spectra of PbC1, and its mixtures with KCl have been determined at 505 "C. Fused PbCl, shows absorptions at 120 (depolarized) and 205 cm-' deformation mode (polarized). These can be assigned to CI-Pb-Cl (v,, El) and Pb-CI stretching mode (vl, Al), respectively, since [PbCl,]ion-like local structure is predominant in the fused state. A chemical shift of the 205 cm-' line to 230 cm-' occurs with increasing KCl concentration, indicating that the chain structure of the [PbCI,]- ions is broken into individual [PbCl,]- ions.3o8Some phase diagrams that have been investigated are shown in Table 10.309-321 N. V. Karpenko, Vestnik Leningrad. Uniu. (Fiz. Khim.), 1973, 89. R. Oyamada, J. Phys. SOC.Japan, 1974, 36, 903. 309 T. P. Bortnikova, E. K. Akapov, and V. A. Ocheretnvi, Zhur. neorg. Khim., 1974, 19, 1066. 310 I. I. Il'yasov, M. Davranov, and I. I. Grudyanov, Zhur. neorg. Khim., 1974, 19, 1710. 311 R. V. Chernov and V. V. Bugaenko, Zhur. neorg. Khim., 1973, 18, 3096. 312 I. I. II'yasov, K. I. Iskandarov, and A. G. Palobekov, Izuest. V.U.Z., Khim. i khim. Tekhnol., 1974, 17, 611. 313 V. N. Prokhorov, I. V. Krivousova, I. I. Kozhina, and A. I. Efimov, Vestnik Leningrad. Uniu. (Fiz. Khim.), 1974, 89. 314 B. F. Markov, T. A. Tishura, and A. N. Budarina, Ukrain. khim. Zhur. (Russ. Edn.), 1974, 40, 242. 315 G. G. Diogenov and V. F. Kirillova, Zhur. neorg. Khim., 1973, 18, 2830. 316 H. Ohno and K. Furukawa, Report 1972, JAERI-M-5053. 317 K. Matiasovsky, I. Kostenska, and M. Malinovsky, Chem. Zuesti, 1973, 27, 301. 318 K. Matiasovsky and V. Danek, J. Electrochem. SOC., 1973, 120, 919. 319 M. Amorasit, B. J. Holm, and J. L. Holm, Acta Chem. Scund., 1973,27, 1831. 320 A. Haav, T. Muuresepp, and A. Kiisler, Kristallografiya, 1974, 19, 273. 321 M. Davranov, I. I. Il'yasov, and M. Ashurova, Zhur. neorg. Khim., 1974, 19, 1628. 3"7
308
2 Elements of Group II BY R. J. PULHAM
In this Chapter, references which allude to several members of the group appear once only under the element first mentioned. The elements of Groups I1 and I are so closely linked in the field of ‘Molten Salts’ that, to avoid duplication, this section appears once only and can be found in Chapter 1.
1 Beryllium Beryllium reacts with both polycrystalline and single crystals of tungsten to produce the same products. At 700-1200 “C, the phases Be2W ( a = 4.44, c = 7.30 A) and BezzW ( a = 7.24, c = 4.21 A) are formed.’ The determination of the molecular structure by X-ray diffraction of the compounds of beryllium, magnesium, calcium, strontium, and barium has been reviewed.’ The compound BeB, is hexagonal, space group P6/mmrn, with a = 9.800, c = 9.532 8, and 82 boron and 27 beryllium atoms in the unit cell. The structure is built upon pairs of polyhedral (BeB),, units. The B-B, B-Be, and Be-Be distances are 1.62-1.84, 1.90-2.22, and 2.04-2.11 A, re~pectively.~ The Raman spectra of molten Be(N0J2,20H20, Be(N0,)2,4H,0, A1(N0,),,20H2O, and AI(N0,),,9H20 have been recorded and analysed in terms of vibrational modes arising from aquated metal ions, NO; ions, H 2 0 molecules, and hydrolysis products. For Be(NOJ2,4H20,though not for the aluminium salts, the spectra suggest a significant degree of proton transfer from [Be(H20)4]2+to NO;. Solvent-separated metal-NO; ion pairs appeared to be present in all melts.4 The solubility of beryllium oxide, BeO, in aqueous solutions of the alkali-metal hydroxides increases with increasing alkali concentration. With
’ E. A. Vasina and A. S. Panov, Izuest. A k u d . Nauk S.S.S.R., Metal., 1974, 197. ’ M. B. Hursthouse, in ‘Molecular Structure by Diffraction Methods,’ ed. G. A. Sim and L. E. Sutton (Specialist Periodical Reports) The Chemical Society, London, 1973, Vol. 1 , p. 797. R . Mattes, H. Neidhard, H. Rethfield, and K. F. Tebbe, Inorg. Nuclear C h e m . Letters, 1973, 9, 1021. D. J. Gardiner, R. E. Hester. and E. Nayer, J. Mol. Structure, 1974, 22, 327.
64
Elements of Group I1
65
dilute solutions of lithium and sodium hydroxides, B e 0 does not react, but with potassium hydroxide the oxide is hydrated, 3BeO,H,O. At higher alkali concentrations polyberyllates are produced, but the degree of polymerization and the water content of the hydrate diminish in very concentrated solution^.^ Potassium oxoberyllate, K,Be,O,, has been prepared by heating 2.2: 1 K,O : B e 0 mixtures to 600 "C for extended periods. The crystals are monoclinic, space group C:,,-P2/b, with a = 7.09, b = 10.57, and c = 5.70 A, y = 131.3", d(expt) = 2.5, and d(ca1c) = 2.46 for Z = 4. The structure consists of planar dinuclear isolated (BeO), groups as edge-linked triangles. The Madelung part of the lattice energy was calculated to be 1939.7 kcal mol-1 and was approximately equal to the sum of the values for the constituent oxides6 The enthalpy of solution of beryllium in molar sulphuric acid has been determined calorimetrically and the data have been combined with known enthalpies of solution of beryllium sulphate hydrates in sulphuric acid to redetermine the standard enthalpies of formation of BeSb, and its hydrates. These are given in Table 1.'
Table 1 Enthalpies of formation of beryllium sulphate and its hydrates -AHf,298/kcalmol-' Reaction Be(c) + S(rhombic)t-202(g) +. BeSO,(c) Be(c) + S(rhombic) + 202(g)+ 2H2(g) + BeS04,2H20(c) Be(c)+ S(rhombic) +4H2(g) + 402(g) + BeS04,4H20(c)
*
Ref. 7
288.0 *0.1 435.7 k0.1
287.0 0.1 434.7k0.1
286.62 0.5 434.4*0.6
579.3k0.1
578.3*0.1
578.0*0.5
*
t
*,tOther previous determinations Calculation by the crystal-force-field method of the charge density on the F atom, the stretching force constant for the Be-F bond, and the length of the Be-F bond in crystalline LizBeF, show that the Be-F bonds have some covalent character and that there is probably weaker covalent bonding between the Li and F atoms.' The compound y'-Na2BeF4 is monoclinic, space group P2,/n, with a = 5.559, b = 8.070, c = 7.910 A, p = 99"21', and Z = 4. The structure consists of serrated chains of Na-centred octahedra linked by Be-centred tetrahedra. There are two distinct octahedral sites, occupied by Na-1 and Na-2, characterized by extreme distortion, as shown in Figure 1. The Na-1-F distances range from 2.280 to 2.540 A, and from 2.272 to 2.469 A for Na-2-F. The beryllium-centred BeF, tetrahedra are also severely distorted and have angles (mean 109"04') consistent with sp3 hybridization.' The structures of chloroberyllate anions in the compounds MiBeCl, and M'Be,Cl, (M=Tl+ or NO') have been studied by i.r. and B. J. Losev, R . F. Doronkina, and I. V. Vasil'eva, Zhur. priklad. Khim., 1973, 46, 1664. P. Kastner and R. Hoppe, Naturwiss., 1974, 61, 79. ' J . D. Navratil and F. L. Oetting, J. Inorg. Nuclear Chern., 1973, 35, 3943. J. A. McGinnety,-J. Chem. Phys., 1973, 59, 3442. S. Deganello, Acta Cryst., 1973, B29, 2593. ti
66
Inorganic Chemistry of the Main -group Elements
F(1
Figure 1 Dimensions of co-ordination octahedra around the sodium atoms in y'-Na,BeF,. Shared edges are shown by thick lines (Reproduced by permission from Acta Cryst., 1973, B29, 2593) Raman spectroscopy and subjected to (LCAO-MO)CND0/2 calculations. The vibrational spectra are compatible with a higher degree of anionic distortion in the NO' complexes than in those of Tl', and indicate that the ion [Be2C1,]- in TlBe,Cl, may have molecular symmetry similar to that of the polymeric BeCl chain. The C N D 0 / 2 calculations favour a dimeric structure for [Be,Cl,]-.'O New pentadichlorodiberyllates MBe,Cl, (M = K', Rb', or NH,') have been prepared by the reaction of anhydrous BeCl, with the corresponding alkali-metal halides at 2 : 1 molar ratio under nitrogen at 400°C. Identification was by X-ray, i.r., and Raman spectra." The crystal structure of hydrazinium fluoroberyllate, (N,Hs)BeF,, has been determined from X-ray data. The compound is monoclinic, space group P 2 , / c , with a = 5.568, b = 7.305, c = 9.910 A, 6 = 98-25", and 2 = 4. The structure consists of [BeF,]*- tetrahedra (mean Be-F distance = 1.547 A) and [N2H6]" ions linked by hydrogen-bonds.I2 The reaction of BeCl, with AIH, in ether has been followed by i.r. spectroscopy. The reaction proceeds according to: BeC1, + AlH, + HBeC1-t H,AICl HBeCl+ AIH, = BeH, + H2A1C1 Hydridoberyllium chloride was prepared unequivocally by the reaction of BeCl, with BeH, and shown to be the product of the above reaction. When excess AIH, is used, BeH, precipitates from solution, the yield depending on the amount of AlH, added. HBeCl is stable to disproportionation and is In
l' l2
J MacCordick and G. Kaufmann, Ann. Chim. (France), 1973, 8, 181. J . MacCordick, Chem. Ber., 1974, 107, 1066. M. R. Anderson, S. Vilminot, and I. D. Brown, Acta Cryst, 1973, B29, 2961.
67
Elements of Group I1 dimeric in ether, the dimer (1) being associated through Be-H-Be
c1'
'H'
bonds
OEt,
and showing bands at 1330, 1050, 970, 908, 840(sh), 790, and 700 cm-' in this s01vent.l~The reactions of LiAlH, and NaAlH, with BeCl, have been studied in 1 : 1 and 2 : 1 ratios in both Et,O and THF as solvents. No evidence for the previously reported Be(AlH,), was found. In 2 : 1 ratio the reaction of NaAlH, and BeCl, in THF was similar to the reaction of LiAlH, and BeC1, in Et,O. Two surprising aspects of the latter reaction are that the AlH, formed is soluble in Et,O and that a compound Li2BeH2C12can be isolated, rather than a mixture of LiCl and BeH,. The reactions proceed according to: 2LiAlH, + BeCl, + Li2BeH2Cl,+ 2A1H3 Li2BeH2C12 + 2A1H3= LiAlH,Cl + LiBeH,Cl + AlH, The reactions of LiAlH, and NaAlH, with BeC1, in 1: 1 ratio follow the same pattern.', Beryllium ethoxide chloride and solvates of beryllium chloride with ethanol have been isolated from mixtures of Be(OEt),-BeC1,EtOH at 20°C. The i.r. spectra of the compounds ClBeOEt,2EtOH and BeC1,,3EtOH have been measured.lS It has been known for a long time that BeCl, reacts with various aliphatic and aromatic nitrites to give complexes that are stable in the absence of polar solvents, i.e. BeCl,,2RCN, in which Be is tetrahedrally co-ordinated. An addition to this type of compound is beryllium chloride 2(monochlorine cyanide), BeCl2,2C1CN, prepared by the reaction of BeCl, with liquid ClCN. The properties of this compound have been compared with those of BeC1,,2MeCN. Both compounds are stable in an inert atmosphere but decompose at high temperatures; BeC12,2C1CN decomposes at ca. 120"C, but BeC1,,2MeCN at ca. 210°C; both are hydrolysed in water and are generally insoluble in nonpolar solvents. BeC1,,2MeCN is sufficiently soluble in hot MeCN to permit recrystallization. Ligand exchange occurs in nucleophilic solvents according to: BeC1,,2NCR+ 2L = BeC12,2L+2RCN (R = C1 or Me; L = Et,O, MeCN, or PhCN) The observed absorption y(C=N) occurs at 2287 and 2338cm-' for BeC1,,2CICN and BeC1,,2MeCN, respectively, compared with 2219 and l3 l4 15
E. C. Ashby, P. Claudy, and R. D. Schwartz, Inorg. Chem., 1974, 13, 192. E. C . Ashby, J. R. Sanders, P. Claudy, and R. D. Schwartz, Inorg. Chem., 1973, 12, 2860.
E. P. Turevskaya, N. Ya. Turova, and A V. Novoselova, Zhur. neorg. Khim., 1973, 18,2925.
68 Inorganic Chemistry of the Main -group Elements 2254 cm-’ for ClCN and MeCN, respectively.’6 Beryllium perchlorate dihydrate has been prepared by the reaction of BeCl, with HClO, followed by vacuum evaporation, and also by heating BeC1, with HClO,,H,O up to the melting point of the mixture. uiz. 60°C. The i.r. spectrum of the product reveals the presence of [Be(H,O),]” and [Be(ClO,),]”- ions. Be(C10,),,2H,O melts at 8O”C, and at 150°C an 0x0- or hydroxy-containing compound is formed. At 190-265 “C HClO, is lost, and the solid residue is Be4O(C10J6. Further heating to 290 “C yields BeO.” The i.r. (400-3700 cm-‘) and n.m.r. spectra of beryllium and aluminium nitrilotriacetates KBeX, HBeX,2H20, KBeX,2H20, A1X,4H20, and A1X [X = N(CH,CO,):-] and their deuteriated analogues have been measured. An equilibrium: B e X - + H 2 0 = Be(0H)HXduring which a mutual transition between two complex types, with N-Be and N-H bonds, occurred, was detected in aqueous KBeX,2H20 solution. This equilibrium was shifted to the right with acidification of the solution.’* A compound between dioxo-octa-acetatoberyllium and ammonia, Be6O2(0Ac),(NH3),,has been prepared by heating Be6O,(OAC), in
Figure 2 Schematic representation of a molecule of tri-p- hydroxo-tri(pyridine -2-carboxylato) triberyllium (Reproduced by permission from Acta Cryst., 1974, B30, 462) l6
J . MacCordick, Compt. rend., 1974, 278, C, 1177. L. R. Serezhkina, Z. I. Grigorovich, V. N. Serezhkin, N . S . Tamm, and A . V. Novoselova, Doklady Akad. Nauk S . S . S . R . , 1973, 211, 123. A. I. Grigor’ev, L. V . Nikitina, and N. I. Voronezheva. Zhur. neorg. Khim., 1973, 18, 1755.
Elements of Group II
69
liquid ammonia in a sealed arnp0u1e.l~ The crystal structure of tri-phydroxo-tris(pyridine-2-carboxylate)triberylliummonohydrate, Be,(OH)3(C,H,NCO,),,H,O, has been determined as monoclinic, space group P2,/c, with a = 15.914, b = 9.262, c = 15.480 A, p = 105.43”, and 2 = 4. The structure is shown schematically in Figure 2. Each Be atom is surrounded by a distorted tetrahedral arrangement of two hydroxide oxygen atoms ( 0 - 3 and 0 - 9 for Be-1) (Be-0 distance = 1.58 A) and the chelating nitrogen (N-1 for Be-1) and carboxylic (0-2 for Be-1) atoms of one picolinato-group (distances Be-0 = 1.65, Be-N = 1.‘79A). The oxygen atom of each hydroxide group (0-3, 0-6, and 0-9) is bonded to two beryllium atoms so that these atoms make a six-membered planar ring reminiscent of the cyclic arrangement (2) in [Be3(0H),]”, with average values Be-0 = 1.85 A,
LBeOBe = 229”. The planar picolinato-groups ‘are in the orthogonal position with respect to this ring. Two chelating N atoms (or two chelating 0 atoms) are located below the Be-0 ring while the third is above, as in a trans compound. The hydrogen-bonded water molecule is in an interstitial position.” Syntheses of new chelates, namely bis(3’-chloroacetoacetanilidato)beryllium(n), bis(4’-bromoacetoacetanilidato)beryllium(11), bis(2’,5’bis(acetoacet- 1‘dime thoxy-4’-bromoacetoacetanilidato)beryllium(11), naphthanilidato)beryllium(II), bis(3-nitro-3’-chloroacetoacetanilidato)beryllium(u), bis(3-nitro-4’-chloroacetoacetanilidato)beryllium(11), bis(3nitro-2‘,4‘-dichloroacetoacetanilidato)beryllium(11), and bis(3-nitro-2’,5’dichloroacetoacetanilidato)beryllium(II) have been described. The nitrocompounds were obtained by the reaction of the parent chelates or the ligands with Be(N03), in acetic anhydride. The i.r., n.m.r., and mass spectra of the compounds have been discussed.21The ability of organic solvents to and beryllium-5,7-dihalogeno-8extract beryllium-8-hydroxyquinoline hydroxyquinoline complexes decreases in the order: iso-CsHI1OH> PhNO, > CHCl, > C,H,Cl, > C,H, > hexane > CCl,.” 19
20
’’ 22
A. I. Grigor’ev, L. N. Reshetova, and A. V. Novoselova, Zhur. neorg. Khim., 1974, 19, 1995. R. Faure, F. Berth, H. Loiseleur, and G . Thomas-David, Acta Cryst., 1974, B30, 462. J. N. Patil, Indian J. Chem., 1974, 12, 189. A. I. Sevast’yanov and N. P. Rudenko, Vestnik Moskov. Uniu., Khim., 1973, 14, 233.
Inorganic Chemistry of the Main -group Elements
70 2 Magnesium
The Mg-Ga phase diagram has been investigated by d.t.a. and X-ray diffraction methods. The compound Mg,Ga, is formed in this system and melts peritectically at 200°C to decompose into MgGa, and melt. No high-temperature modification of MgGa, was detected.,' The laves phase Mg,LiZn, has been examined by X-rays, and the structure corresponds to the centrosymmetric space group P6,lmmc. There is a superstructure with ordered distribution of Li and Zn atoms in each layer, leading to a doubling of the cell dimension The crystallographic parameters and the temperature dependence of the electrical resistivity of Mg,Mn,-,Te, have been measured. The lattice parameter a increases smoothly with increasing temperature. Mgo32Mno 68Te2and MgTe, are semiconductors, like MnTe,. The activation energies for conduction are 0.48 eV for x = 0.32 and 0.42 eV for MgTe. The compounds MgTe, and MnTe, are essentially similar structurally and electronically, and they form a continuous solid solution over the entire composition range." The solubilities of MgSe and CdSe in PbSe, and the extent of non-stoicheiometry in the systems Mg,Pb,-,Se and Cd,Pb,_,Se, have been determined between 400 and 800°C. The solubilities appear retrograde in that the solubility of MgSe is less dependent on temperature than that of CdSe.'" The solubilities of Mg, Ca, Cd, Zn, and Hg in PbTe are compared at 250-800°C. Mg, with Cd and Zn, shows retrograde solubility in this melt Magnesium reacts with fused NaOH at 400°C to give MgO and NaH as primary products. Subsequently, NaH dissociates to produce gaseous hydrogen, and the sodium also liberated reacts with NaOH to produce NazO." The reaction of Mg with molten LiOH, NaOH, and KOH is considered to be insignificant, however, at low temperatures but increases sharply at 610, 570, and 540 "C for LiOH, NaOH, and KOH, respectively, only to decrease again at higher temperatures up to 900°C. As before, alkali metal and hydrogen are liberated.29 An investigation has been made of the energy shifts of the K1.,emission lines of magnesium, sodium, aluminium, and silicon in their binary compounds. The shift varies with the ionic character of the chemical bond, so as to form two straight lines for compounds of these elements. Thus the MgKl,, energy shifts of MgC2, Mg,N2, MgO, and MgF, followed one linear relationship, in agreement with theory, but those for the compounds of Mg W. Staehlin, J. Less-Common Metals, 1973, 32, 395. E. V. Mel'nyk and P. I. Kripyakevich, Kristallogrufiyu, 1974, 19, 645. 2 5 S. Anzai, K. Watanabc. M. Iwama, A . Morita, and S. Vanagisawa, Japan. J. Appl. Phys., 1973, 12, 1289. '' B. J. Sealy and A. J. Crocker, J. Materials Sci., 1973, 8, 1247. 27 B. J . Sealy and A. J. Crocker, J. Materials Sci., 1973, 8, 1731. 2R G. A . Vorob'ev and V. L. Kubasov, Zhur. neorg. Khim., 1974, 19, 339. 2 y V. K . Shcherbakov and S. I . Kuznetsov, Zhur. priklad. Khim., 1973, 46, 2.555. 23
24
71 Elements of Group I1 with Al, Sn, Bi, P, S, Br, and C1 followed another. Similar results were obtained for the compounds of Na, Al, and Si.'" The magnesium borides MgB, and MgB, have been prepared at high temperatures in a sealed molybdenum vessel from mixtures of the elements. By using an excess of Mg, the vapour pressure of the metal inhibited thermal decomposition of the compounds during the synthesis. MgB, i s orthorhombic, space group Pnam, with a = 5.464, b = 7.472, c = 4.438 A, and Z = 4 . The structure is based on chains of pentagonal pyramids of boron atoms in which the average B-B distance is 1.787A. Interchain B-B bonds of 1.730A are responsible for the three-dimensional framework. The magnesium atoms are located in tunnels and form zigzag chains. A comparison with the structures of ThB, and CrB, shows that the size of the metal atom plays an important role in the nature of the boron framework. The boron pentagonal pyramid in MgB, is a new feature of B-rich borides since this type of co-ordination polyhedron was previously found only in B,, icosahedra.31Magnesium chloride is reported to react with LiAlH,, LiBH,, and NaAlH, in ether to give Mg(AlH,),,LiAlH,. With mixtures of MgCl,, LiBH,, and NaAlH,, the compounds Mg(A1H4),,2LiBH, and NaCl are formed using a 1:2 :2 molar ratio of reactants. Using a ratio of 1: z= 3 :4 produces Mg(AlH,),,LiA1H,.32 The enthalpies and energies of formation of the magnesium carbonates nesquehonite (MgC03,3H,0) and hydromagnesite (5Mg0,4CO2,5Hz0) have been determined by combining enthalpy data from solution calorimetry in HCl with previously determined heat-capacity data. For are -412 and -473 kcal mol-', respecMgC0,,3H2O, AG& and tively. For 5Mg0,4C0,,5H20, the values are -1402 and -1557 kcal mol-', respe~tively.~~ The reaction of powdered magnesium with nitrogen yields Mg3N, with the anti-bixbyite-type structure. The nitride forms double nitrides with Si,N, and Ge3N, of the form MgSiN, and MgGeN,, respectively. These compounds possess the wurtzite structure, with a = 5.279 and 5.494, b = 6.476 and 6.611, c =4.992 and 5.165 A, respectively. A new double nitride, Mg,Ca,N,, is reported from the Mg3N,-Ca3N, The preparation of mangesium phosphide, MgP,, has been achieved from MgSiP, by melting it with a Bi-Pb-Sn (4:2: 1 weight ratio) alloy at 1100°C in a corundum crucible followed by slow cooling. The excess metal was washed away by alloying with mercury, revealing the new compound MgP,, which crystallized with the MgSiP,-type structure. Crystals are monoclinic, space E. Asada, Japan. J. Appl. Phys., 1973, 12, 1946. R. Naslain, A. Guette, and M. Barret, J. Solid State Chem., 1973, 8, 68. 32 K. N. Semenenko, B. M. Bulychev, and K. B. Bitsoev, Vestnik Moskou. Uniu., Khim., 1974, 15, 185. '' R. A . Robie and B. S. Hemingway, J. Res. U.S. Geol. Survey, 1973, 1, 543. 34 J. David, Rev. Chim. mine'rale, 1972, 9, 717, 30 3'
72
Inorganic Chemistry of the Main -group Elements
group P2,/c, with a = 5.142, b = 5.079, c = 7.518 A, and /3 = 98.64°.3' The structure of a-Mg,Sb, has been determined as space group P3m1, with a = 4 . 5 6 8 and c =7.229A. The structure is of the La,O,-type, with d(ca1c) = 4.02 for Z = 1. Single crystals for the X-ray work were prepared by cooling a melt of composition 3Mg + 2Sb with a small excess of Mg from 1100°C to ambient temperature under argon. The compound has a metallic appearance and is resistant to air. The structure can be described in terms of SbMg, units. Each of these units contains the crystallographically independent Sb atom and the two crystallographically different magnesium atoms Mg-1 and Mg-2, as shown in Figure 3. Six of the Mg atoms are
2')
Figure 3 Arrangement of magnesium atoms around Sb in a-Mg,Sb,. The bond lengths are given in A (Reproduced by permission from Acta Cryst., 1974, B30, 2006) arranged at the corners of a trigonal antiprism whose centre is occupied by the Sb atom. The seventh Mg atom approximates the Sb atom in the three-fold axis of the group. No short Mg-Mg distances are present in this structure, in contrast to the short Ca-Ca, Sr-Sr, and Ba-Ba distances in the compounds Ca,Sb,, CasBi,, Sr,Sb,, Sr,B, and Ba2Bi. With the magnesium compounds of the main Group V elements there is a negligible volume contraction from the original volumes of the individual components, in contrast to the corresponding compounds of Ca, Sr, and Ba, in spite of the more salt-like formulae of the Mg compounds. Presumably more extensive transfer of electrons occurs from the heavier alkaline-earth metal atoms than for Mg." Magnesium arsenate, Mg,AsO,, is tetragonal, space group 1 4 2 4 with a = 6.783, c = 18.963 A, d(obs) = 3.9, and d(ca1c) = 4.03 for Z = 6 . The structure was determined by X-ray diffraction on crystals 3%
36
'I. Ciibiiiski, k.Cisowaska, W. Zdanowicz, Z . Hcnkie. and A. Wojakowski, Krist Tech., 1974, 9, 161. M Martinez-Ripoll. A. Haase, and Ci. Brauer. Acta Cryst., 1974, B30, 2006.
Elements of Group I1
73
from a melt of MgCO, and AszOs.The structure contains two distinct AsO, groups, with average As-0 distances of 1.678 and 1.690 A. Two of the three Mg2+ions are octahedrally co-ordinated and the third occupies a site of 4 ~yrnrnetry.~~ The reaction of Mg and 0 atoms in matrices of Ar, Kr, Xe, and 0 at 20.4 K has been studied by i.r. spectroscopy in the region 2 0 0 4 0 0 0 cm-l. Reaction takes place, as evidenced by a band in the Mg-0 stretching region, reproducible in all matrices. Substitution by "0 isotope gives results that suggest that the absorption is due to Mg,O,, whose formation is supported by the crystal structure of the solid phase. It is suggested that the species is a planar six-membered ring of alternate Mg and 0 atoms with bond angles O M 0 100" and MgOMg 140".38The enthalpy of formation and heat capacity of MgO have been determined calorimetrically between 298 and 1600 K. The enthalpy/cal mol-' is given by:"
HT - H298 = 11.18 (T/K) + 0.00067 (T/K)' + 2.27 X 10' (K/T) - 4154 The lattice energies of the alkaline-earth metal oxides have been calculated from equations based on the Born model and containing terms accounting for van der Waals interactions. The results, in kcal mol-l, are MgO, -905; CaO, -815; SrO, -767; and BaO, -736. These lattice energies, when combined with the appropriate thermochemical data, give 149 f 8 kcal mol-' for the process O(g) 5 02-(g), which is less than most values previously calculated for this process. The new smaller value is attributed to the higher more accurate compressibilities used in evaluating the lattice energies of these oxides.,' The X-ray-stimulated photoelectron emission of single crystals of Mg(OH), has been studied. A marked anisotropy was observed in the valence-band region. For the 1010 plane, three maxima were found at 4.6, 8.8, and 12.0eV, which can be assigned to the TI,, E,, and A,, states, respectively, if regular 0, symmetry is assumed for the ligand field. For the 0001 plane the A,, band disappears, which is attributed to the fact that in Mg(OH), the octahedral symmetry is reduced to D,, by the special orientation of the O H dipoles parallel to the c - a x i ~ . ~ ' The K f3-emission and K-absorption spectra of chlorine in MgCl,, CaCl,, SrCl,, and BaC1, have been determined. The Kf3 emission spectra consist of a prominent band KP, and its sub-bands KPx and KP5, although the sub-bands are ambiguous in MgC12, as shown in Figure 4. Going to the metal chlorides of higher atomic number, the half-width of the KP, band (which is due to the transition 3p + 1s within the C1- ion) decreases, and the sub-band K& is clearly separated from the KP, band. This general feature has also been found for the KP-emission of the C1- ion in the 37 38 39 40 41
N. Drishnamachari and C. Calvo, Acta Cryst., 1973, B29, 2611. M. Spoliti, G. Narini, C. S. Nunziante, and G. De Maria, J. Mol. Structure, 1973, 19, 563. D. Sh. Tsagareishvili and G. G. Gvelesiani, Teplofiz. Vys. Temp., 1974, 12, 208. S. Canton, J. Chem. Phys., 1973, 59, 5189. F. Freund and L. H. Scharpen, J. Electron Spectroscopy Related Phenomena, 1974, 3, 305.
Inorganic Chemistry of the Main -group Elements
74
SrCI,
KP 1
28 10
2820
2810 Photon energyleV
2820
Figure 4 KP emission spectra of C1- ion in Group I1 and Group I metal chlorides alkali-metal chlorides, shown for comparison in Figure 4. This probably relates with the amounts of ionic character of the bond of these chlorides, because the bond is largely ionic and the valence band arises from the 3p state of the Cl- ion. For alkali-metal, alkaline-earth, and transition-metal chlorides it can be shown that when the difference in electronegativity between metal and chlorine is more than 2.0 and the amount of ionic character is larger than 63%, the KP, band is appreciably narrower, and the sub-band appears to be separated from the KP, band. However, when the difference is smaller than 1.8 and the chlorides are largely covalent, the KP, band is very wide, and the KPx band is ambiguous. Thus the width of the
Elements of Group II
75
KP, band becomes narrow or broad when the bond is largely ionic or ~ovalent.~' The i.r. spectra of the alkaline-earth dihalides MC1, (M = Mg, Ca, Sr, or Ba) trapped in solid Kr matrices at 2 0 K have been determined. From precise measurements of changes in the vibrational modes on isotopic substitution, a linear configuration for MgCl, and CaC1, is confirmed, and an apex angle of 120" is established for the bent molecule SrCl,. For BaC12, the bond angle was estimated at The i.r. spectra of MgX,,MezO (X= C1, Br, or I), MgBr,,2Mez0, and MgBr,n(CD,),O (n = 1 or 2) have been determined from 4000 to 40cm-', and a complete band assignment has been made. Analysis of the data suggested four-co-ordination for Mg and the existence of 0 bridges in the 1: 1 complexes.44 Complexes and reactions of substituted magnesium amides with isobutyric acid esters have been studied. The reaction of Me,CHCO,R (I) ( R = M e or Me3C) with (Me,Si),NMgBr in toluene leads to co-ordination complexes Me,CHC(OR),OMg(Br)N(SiMe,),, which decompose after several hours at ambient temperature or immediately at 60 "C in vacuum. Mixing (I; R = Me) with [(Me,Si),], produced the chelate structure (3), which evolved NH(SiMe,), at 60°C under vacuum to produce (4). The compound (3) can
(3)
(4)
also be prepared from Me CHCOC(MeJC0,Me atld [(Me,Si),N],. The compounds were characterized by hydrolysis and i.r. and n.m.r. ~pectra.~' Addition of magnesium carbonate to aqueous solutions of disodium ethylenediaminetetra-acetate at 25 "C produces the complex salt Na2[Mg(C2H4N2(CH,CO,),],4H,O. Thermal analysis of this complex shows an endothermic process at 140--145"C, corresponding to the loss of the water molecules. At 500 "C, two carboxy-groups are lost ex~thermically.~~ The crystal structure of magnesium ethylenediaminetetra-acetate nonahydrate, Mg,[C,H4N2(CH2C0,),],9H,O, has been determined as orthorhombic, space group Pbcn, with a = 11.622, b = 9.49, c = 19.26 A, d(obs) = 1.595, and d(ca1c) = 1.57 for Z = 4 . The structure is made up of cations 42 43
44 45 46
C. Sugiura, Phys. Rev. (B), 1974, 9, 2679. D. White, G. V. Calder, S. Hample, and D. E. Mann, J . Chem. Phys., 1973, 59, 6645. J. Kress and J. Guillermet, Spectrochim. Actu, 1973, 29A, 1717. L. Lochmann and M. Sorm, Coll. Czech. Chem. Comm., 1973, 38, 3449. V. G. Dudakov and E. B. Shternina, Zhur. neorg. Khim., 1973, 18, 3116.
76
Inorganic Chemistry of the Main -group Elements
[Mg(H20)6]2f and anions [Mg’C2H,N2(CH2C0,),,H,0]2~ with ethylenediaminetetra-acetate acting as a sexidentate ligand. The Mg’ atom is heptaco-ordinated, in a pentagonal bipyramid with two 0 atoms, two N atoms, and an H,O molecule in the equatorial plane and two 0 atoms at the apices. The complex anion is closer to the analogous heptaco-ordinated complexes of iron than of manganese. The complex ions are mutually bound, with hydrogen bonds, into a three-dimensional framework, due to the presence of both water of crystallization and water molecules in the co-ordination sphere of rnagne~ium.~’Disodium magnesium ethylenediaminetetra-acetate tetrahydrate, Na,Mg{C2H,N,(CH2CO2),),4H20, is also orthorhombic, with space group P2,2,2, and a = 13.36, b = 16.52, c = 7.71 A, d(obs) = 1.65, d(ca1c) = 1.69 for 2-=4. This structure is composed of infinite chains of -MgL(H20)-Na2(H20)3(where K L = edta),
Figure 5 Environment of the magnesium atom, with hydrogen-bond lengths (A), in magnesium dichromate hexamethylenetetramine hexahyd rate (Reproduced by permission from Acta Cryst., 1974, B30, 22) 47
A . I. Pozhidaev, T. N . Polynova, M. A. Porai-Koshits, and V. A. Logvinenko, Zhur. strukt. Khim., 1973, 14, 746.
Elements of Group I1
77
with Na-Na distances 3.77 A.48Hexamethylenetetramine (L) reacts with magnesium and alkaline-earth-metal halides MX, (M = Mg, Ca, Sr, or Ba; X = Br or I) to give MgBr,,2L, 10H,O, Mg12,2L,8Hz0, CaBr2,L,6H20, CaBrz,2L,10Hz0, Ca12,2L,8H20, CaI,,4L,12Hz0, SrBr,,2L,8Hz0, SrI,,2L,8Hz0, Sr12,4L,12Hz0, BaBr,,2L,8Hz0, and BaI,,2L,8Hz0.49 Hexamethylenetetramine also forms a complex with magnesium dichrohas been mate. The structure of this complex, MgCr,0,,[(CH2)6N,]2,6Hz0, determined by X-ray diffraction. The crystals are triclinic, space group P i , with a=10.02, b=13.68, c = 9 . 8 1 A , a=96.1", /3=87.9", and Z = 2 . The structure is characterized by two nearly tetrahedral CrO, groups joined through a shared 0 atom, an octahedral [Mg(H,0),I2+ group, and two hexamethylenetetramine molecules linked by hydrogen bonds. The environment of the Mg atom is shown in Figure 5. The magnesium atom is a completely hydrated cation [Mg(H20)6]2' and does not co-ordinate with the dichromate 0 atoms, but the octahedron is slightly distorted. Thus the angles OMgO range from 85.8 to 93.2" and the Mg-0 distances from 2.06 to 2.13A. The mean of the two longer bonds from Mg to 0 - 2 and 0 - 5 is 2.13 A; the mean of the other four is 2.08 A. This is an interesting feature because the six water oxygen atoms are equally bonded to three atoms (the magnesium and two hydrogen atoms) and have no other bond. Usually, the distance Mg-0 is lengthened when the water oxygen atom acts as an acceptor to hydrogen bonds from other Magnesium picolinate dihydrate, Mg(Cs&NC02),,2H,0, crystallizes in the monoclinic system, space group P2,/c, with a = 11.68, b = 8.85, c = 16.00 A, /3 = 115.46", Z = 4. Each of the two picolinate anions (5) are co-ordinated to magnesium through N and
carboxylic 0, and the co-ordination at Mg is made up to six by two water molecules. The octahedron around the cation is distorted, with the metalnon-metal distances shown in Figure 6. The molecule is dihedral, with an angle of 95" between the two pyridine rings, and is hydrogen-bonded to other molecules by the water molecules." The MgKP,,.l X-ray emission spectra from Mg(hfa~)~,2H,O and Mg(aca~)~,2H,O (hfac = hexafluoroacetylacetonate, acac = acetylacetonate) have been determined, The integrated areas of the peaks are in the ratio 1 : 1.3 for these complexes, which indicates that fluorine in the ligand causes a charge withdrawal from 48
49
"
A. I . Pozhidaev, T. N. Polynova, M . A. Porai-Koshits. and V. G. Dudakov, Zhw. strukt. Khirn., 1974, 15, 160. Z . Ysmanova, P. Yun, B. Imanakunov, and A. Karabekov, lzuest. Akad. Nauk Kirg. S.S.R., 1973, 66. F. Dahan, Acta Cryst., 1974, B30, 22. J. P. Deloume, H. Loiseleur, and G. Thomas, Acta Cryst., 1973, B29, 668.
78
Inorganic Chemistry of the Main -group Elements i
C(3)
n
Figure 6 Co-ordination of magnesium in magnesium picolinate dihydrate. DistanceslA from Mg are 0-1, 0-4, 2.05; 0 - 3 , 2.04; 0-6, 2.06; N-1, 2.19, and N-2, 2.25. (Reproduced by permission from Acta Cryst., 1973, B29, 668) magnesium. In the hfac complex, magnesium is octahedrally co-ordinated by oxygen, and though only one peak is expected in association with the Mg-ligand a-bond formation, two peaks are observed. This is attributed to .rr-bonding. Both ligands have lone pairs on oxygen with u-bonding potential to magnesium and, in addition, certain T-orbitals have the correct symmetry to interact with 3p orbitals on Mg. The observed spectra are assigned as Mg(hfac),,2H20 Mg(acac),,2H20
1292 eV 1297 eV 1292 eV
ligand-Mg bond (a) ligand .rr3-Mg 3 p bond ( T ) H,O-Mg bond (a)
1294 eV
ligand-Mg bond (a)
1297 eV
ligand-Mg bond ( r )
Kinetic data as a function of temperature have been reported over the range 5-35 "C for the reactions of Mg2+with ATP4-, ADP3-,and CDP3-. (ATP4-= adenosine 5'-triphosphate, ADP3-= adenosine 5'-diphosphate, and CDP3-= cytidine 5'-diphosphate). The results are compatible with a mechanism involving complexation with the phosphate moiety, the ratedetermining step being the expulsion of a water molecule(s) from the inner hydration sphere of Mg2+.The results are completely consistent with an S,1
'*
D. E. Fenton, C . I. Nicholls, and D. S. Urch, Chem. Phys. Letters, 1973, 23, 211
Elements of Group I1
79
complexation mechanism, and the activation enthalpy is considered to be a more reliable mechanistic criterion than rate constant^.^,
3 Calcium The vapour pressures of calcium and strontium have been determined by a transpiration method at 1126-1300 and 1086-13 10 K, respectively. The temperature dependence of the vapour pressure is given by the equations for Ca, loglo(piatm)= 4.93 - (8550 K/T) for Sr,
loglo(p/atm)= 4.75 - (7720 K/T)
The sublimation enthalpies, AH,"b,for the elements are 43.0 and 39.5 kcal mol-' at 298 K for calcium and strontium, respectively .', The intermetallic phase Ch.05Lil.05Sn has been prepared by melting the elements in the appropriate proportions for 1h at 900°C under argon and subsequently cooling. The compound crystallizes trigonally, space group P3ml-C;,, with a = 4.94, c = 10.90 A, d(obs) = 3.49, and d(ca1c) = 3.55 for Z = 3 . The structure is a new variation of the CaIn, type, with twodimensional infinite, corrugated hexagonal LiSn networks. Within these networks, the Li or Sn atoms are surrounded by three Sn or Li atoms to give a flat trigonal pyramid, formed by the four atoms, with the pyramid axis vertical to the network plane.55 Crystal data have been obtained for calcium borate chloride, Ca2B03C1. Crystals grown from a CaCl, flux at 800 "C were monoclinic, of space group P2,/c, with a = 3.948, b = 8.692, c = 12.402 A, p = 100.27", d(obs) = 2.76, and d(ca1c) = 2.766 for Z = 4.56Calcium gallium oxide, CaGa,O,, has been prepared by melting CaO and Ga,O, in 1: 1 molar ratio. The compound crystallizes in the space group Cgh-P2/c, with a=7.992, b=8.830, c = 10.585 A, p = 94.72", and Z = 8." A calorimetric determination has been made of the enthalpies of formation of the carbonates CaMg,(CO,), and Mg2(OH),C0,,3H,0, and their energies of formation have been determined. The solution enthalpies in HC1 were combined with existing heat-capacity data to deduce enthalpies and energies of formation at 298K. These are CaMg,(CO,),, 1083, 1004; Mg,(OH),C03,3H,0, 698, 614 kcal mol-', r e s p e ~ t i v e l y The . ~ ~ Ca-Si phase diagram has been investigated by thermal analysis and structural determinations, and the liquidus differs considerably from those of existing phase diagrams. Ca,Si and CaSi melt congruently at 1305 and 1315"C, respectively; CaSi, melts incongruently at 1033 "C, and the m.p. of Ca is given as 53 54
55
'' 57 58
J . L. Banyasz and J. E. Stuehr, J. Amer. Chem. SOC., 1973, 95, 7226. G. De Maria and V. Piacente, J. Chem. Thermodynamics, 1974, 6, 1. W. Mueller and R. Voltz, Z . Naturforsch., 1974, 29b, 163. J. Majling, V. Figusch, J. Corba, and F. Hank, J. Appl. Cryst., 1974, 7, 402. H. J. Deiseroth and H. Miiller-Buschbaum, Z . anorg. Chem., 1973, 402, 201. B. S. Hemingway and R. A. Robie, J . Res. U.S. Geol. Suruey, 1973, 1, 535.
80
Inorganic Chemistry of the Main -group Elements 833 (most values are close to 850) and that of Si as 1408"C.59CaSi loses Ca under vacuum at 740"C, and the decomposition is accelerated with increasing temperature. Pure CaSi, is obtained by maintaining the temperature at 880--1000°C. The thermal decomposition of CaSi in the presence of oxygen at 400--1000°C results in the reaction:
4CaSi + 3 0 , + Ca,SiO,
+ 2 C a 0 + 3Si
With nitrogen, CaSi forms Ca,SiN, below 900"C, with liberation of Si. At 900-1200 "C, pure CaSiN, is obtained.60 Measurements of the electrical resistivity of high-purity silicides and germanides from 20 to 800°C show that CaSi,, CaGe,, and SrSi, are metallic conductors whereas BaSi,, BaGe,, and SrGe, possess semiconducting properties. The difference can be attributed to differently structured anion sublattices and different interatomic distances in the metal sublattices.61 The reaction of CaO with SiO at high temperatures has been studied. At 1450-1680 "C, the compounds CaSi, and 2Ca0,Si02 are formed. The process is complicated by the further reaction of SiO with 2CaO,SiO, to produce Ca0,Si02.6' A diffractometric study has been made of the high-temperature transformations of calcium germanates. The compound 3Ca0,GeO has the following structures: at 25 "C, triclinic, space group C1, a = 12.427, b = 7.235, c = 25.44 A, a = 89.83", p = 89.73", y = 89.78"; at 820 "C, triclinic, C1, a = 12.547, b = 7.284, c = 25.79 A, a = 89.92", p = 89.90", y = 89.83"; at 1060 "C, slow decomposition occurs to 2Ca0,GeOz; at 1410 "C, hexagonal, space group P3m, a = 7.317, c = 26.134 A. The compound 2Ca0,Ge02 has the following structures: at 25"C, orthorhombic, space group Pcmn, a = 5 . 2 5 , b = 6.815, c = 11.40 A; at 1480 "C, hexagonal, space group P43rnc, a = 5.69, c = 7.42 bi."' The alkaline-earth hexammoniates Ca(NH,), and Sr(NH,), thermally decompose to metal and metal amide. At 40 "C, the thermal decomposition rate constants for Ca(NH,), and Sr(NH,), are 2.512X and 3.715 X IO-'min-', respectively, and at 63°C these increase by 1-2 orders. The respective activation energies of the thermal decompositions are 4 1 and 33 kcal m01-l.~~ The structure has been determined of crystals of calcium gallium nitride, CaGaN, prepared by the reaction: Ca,N, + Ga + iN, + 3CaGaN at temperatures between 800 and 1000°C. The structure is built up of layers of gallium atoms strongly bonded to N atoms (1.863 A).The Ca 5y
" 61 62
b3 64
E. Schuermann, H. Litterscheidt, and P. Fuenders, Arch. Eisenhuettenw., 1974, 45, 367. A. Gourves and J. Land, Compt. rend., 1974, 278, C, 617. J. Evers and A. Weiss, Materials Res. Bull., 1974, 9, 549. G. N. Kozhevnikov, A. G. Vodop'yanov, N. G. Moleva, and A. V. Serebryakova, Izvest. Akad. Nauk S.S.S.R., Metal., 1973, 61. A. I. Boikova and A. 1. Domanskii, Doklady. Akad. Nauk S.S.S.R., 1974, 214, 633. M. M. Tarnorutskii, S. G. Artamonova, and I . S. Filatov, Zhur. neorg. Khirn., 1974, 19, 889.
Elements of Group I1 81 atoms are between the layers and are surrounded by five N atams, as shown in Figure 7. The bond distances Ca-N’ and Ca-N are 2.529 and 2.418 A, respectively. These are similar to those found in ionic nitrides: Ca3N2, 2.46 A; Ca2N, 2.43 A; CallNs, 2.30-2.50 A; and CaGeN,, 2.44 A, and this suggests that calcium is in the ionic form. The compound has been found previously to possess a high electrical conductivity and metallic p r o p e r t i e ~ . ~ ~
Q
Figure 7 Structure of CaGaN (Reproduced by permission from Acta Cryst., 1974, B30, 226)
A new hydrate of calcium nitrate has been identified, P-Ca(N03),,2M,0. The compound crystallizes from a supersaturated aqueous solution in the monoclinic space group C2/c, with lattice parameters a = 7.79, b = 6.88, c = 12.22 A, = 90.0°, d(ca1c) = 2.03 for Z = 4. The Ca2+ion is surrounded by ten 0 atoms.66A new calcium phosphide, Cap,, is reported to form by 65
6h
P. Verdier, P. L’Haridon, M. Manunaye, and R. Marchand, Acta Cryst., 1974, B30, 226. A. Leclaire, Acta Cryst., 1974, B30, 605.
82 Inorganic Chemistry of the Main -group Elements heating Ca and red P in a 3 : 1 ratio in a quartz ampoule at 650 "C. The black Cap, crystals are triclinic, space group P i , with a = 5.590, b = 5.618, c = 5.66 A, CY = 69.96", p = 79.49", y = 74.78", and 2 = 2.67Recent progress in the chemistry of calcium phosphates, especially apatites, their composition, structure, and properties have been reviewed.68369 The compounds Ca,Sb and Ca,Bi have been prepared by heating the stoicheiornetric amounts of the elements at 1350°C under argon followed by slow cooling. The compounds crystallize tetragonally in the space group 14/rnrnm, with a = 4.67, 4.72, c = 16.28, 16.54 A, d (calc) = 3.76, 5.2, respectively, and Z = 4 . The Sb and Bi atoms are co-ordinated to nine Ca atoms only, to form a distorted tetragonal antiprism, above the plane of which another Ca atom is located as shown in Figure 8.70A more complicated structure is
Figure 8 Unit cell of Ca,Sb and Ca,Bi (Reproduced by permission from Z . Naturforsch., 1974, 29b, 13) adopted by Ca,Bi,. This compound is prepared by cooling a melt of stoicheiometry 3Ca+ Sb with a small excess of Ca from 1150 "C to ambient temperatures under argon. Single crystals are obtained by leaching with liquid ammonia. These are orthorhombic, space group Pnrna, with a = 12.502, b = 9.512, c = 8.287 A, d(ca1c) = 3.81 for 2 = 4. There are four W. Dahlmann, and H. G. Von Schnering, Naturwiss., 1973, 60, 518 T. Kanazawa and H. Monma, Kagaku No Ryoiki, 1973, 27, 662. T. Kanazawa and H. Monma, Kagaku No Ryoiki, 1973, 27, 752. '' B. Eisenmann and H. Schaefer, 2. Naturforsch., 1974, 29b, 13. 67 6H
69
Elements of Group I1
83
crystallographically different Ca atoms, and the structure is built up of layers perpendicular to the b direction of the unit cell. Ca-Sb distances range from 3.249 to 3.371 A and Ca-Ca distances from 3.743 to 4.047 A. The interatomic distances indicate partial ionic character of the bonds." The analogous compound of Bi is Ca5Bi,, which is isomorphous with Ca,Sb,, having a = 12.722, b = 9.666, c = 8.432 A, d(ca1c) = 5.298 for Z = 4. Two compounds were originally found in the Ca-Bi system, viz. Ca,Bi, and CaBi,. The stoicheiometry of Ca,Bi, was later revised to Ca,Bi,. The present work decides that this is more appropriately designated Ca5Bi,. The structure contains two kinds of Bi atoms; a ChBi unit, similar to the CaSb unit found in Ca,Sb,, with Ca-Sb distances 3.423 A, and a CasBi unit, also like that of Ca,Sb in Ca,Sb,, with Ca-Sb distances 3.263 A.72 The deposition of alkaline-earth-metal atoms and ozone molecules at high dilution in argon at 15 K yields species showing intense bands in the i.r. at 800 and 450--650cm-'. Those at SOOcm-' showed the appropriate isotopic shifts for assignment of v3 for the ozonide ion, 0;. The use of scrambled isotopic ozones indicates that the metal cation is symmetrically bound to the ozonide ion, which contains three 0 atoms, with two of these equivalent. In addition, calcium and barium mixtures with ozone contain several metal oxide species tentatively identified as (CaO),, CaO,,BaO, and (BaO),, re~pectively.'~ The formation of alkali-metal and alkaline-earth-metal sulphides and polysulphides from the elements in liquid ammonia has been extensively studied in the past, but the reactions between the metals and hydrogen sulphide in liquid ammonia have drawn detailed attention only recently. It has been suggested that the equilibrium of H,S in this solvent to give the solvated hydrosulphide ion accounts for the formation of KSH even with an excess of metal. With the alkaline-earth metals, effective preparative methods have been developed for the sulphides from H,S in liquid ammonia but anhydrous hydrosulphides have not been obtained. Now, hydrosulphides have been prepared of the form M(SH),,xNH, (M = Ca, Sr, or Ba; x = 4, 6, or 0, respectively) from the metals with H,S in ammonia, but the compounds are stable only at low temperatures. Those of Ca and Sr are stable at -45 "C but decompose to the monosulphides at room temperature. Ba(HS), decomposes to Bas at 100 "C with evolution of a mole of H,S. For M'(SH) (M' = Rb or Cs), thermal decomposition gives polysulphides. The hydrosulphides of Rb, Cs, Sr, and Ba hydrolyse rapidly in moist air.74 Calcium carbonate reacts with low concentrations of SO, in a nitrogen stream at 500 "C initially to form an intermediate product CaS03 and CO,. Subsequently, CaSO, is converted by SO, into CaS0, and sulphur. The formation of CaS is attributed to the reaction of sulphur with CaO liberated 71
M. Martinez-Ripoll and G. Brauer, Actu Cryst., 1974, B30, 1083. A. Haase, and G. Brauer, Actu Cryst., 1974, B30, 2004. D. M. Thomas and L. Andrews, J. Mol. Spectroscopy, 1974, 50, 220. J. A . Kaeser, J. Tanaka, J. C. Douglas, and R. D. Hill, Inorg. Chem., 1973, 12, 3019.
'' M. Martinez-Ripoll, 73 74
Inorganic Chemistry of the Main -group Elements 84 in the thermal decomposition of CaC03.75Alkaline-earth-metal chlorosulphates have been prepared by the reaction of HS0,Cl with-MCl, (M = Ca, Sr, or Ba). The compounds Ca(SO,Cl),, Sr(SO,C1),,2HSO,Cl, and BaS03C1nHSO, (n = 1, 2, or 3) have been characterized by X-ray diffraction, i.r. spectra, and thermogravimetry. The salts decompose thermally to give a mixture of products, consistent with two Ba(SO,Cl),
+ BaSO,
Ba(SO,Cl),
+ BaCl,
+ SO,CI,
+ 2S0,
The reactions of fluorine with aqueous solutions of alkaline-earth-metal chlorides give different products depending on the Group I1 metal. With MCl, (M = Ca, Sr, or Mg), fluorination leads directly to MF,, but with BaC1, the compound BaF(HF,) is formed. An intermediate step in the reaction involves the formation of BaClF followed by substitution of C1- by HF;." Chelate compounds of calcium, Ca(bn), (Hbn = N-benzoylphenylhydroxylamine) and Ca(zm), (Hzm = N-cinnamoylhydroxylamine), have been prepared by warming ethanolic solutions of the organic ligand and metal salt at pH 11.5 to 50 "C. 1.r. and spectral data indicate that the calcium chelates are inner-sphere complexes analogous to the copper chelates, and are weak electrolyte^.^^ The structure of a-galactose-calcium bromide trihydrate has been determined from X-ray diffraction data. The complex has formula C6HI2O6,CaBr,,3H20 and structural formula (6). Crystals are orthorhombic, space
1'1 6H CaBr, 3H,O
(6)
group P2,2,2,, with a = 19.388, b = 8.746, and c = 8.672 A. An outstanding feature of the structure is the interaction of galactose molecules with Ca2+ ions that are co-ordinated to five hydroxy-groups; 0 - 1 and 0 - 2 , 0 - 3 and 0 - 4 , and 0-6, respectively, from three galactose molecules. The coordination by oxygen is made up to eight by further co-ordination to three water molecules, W(1), W(2), and W(3), as shown in Figure 9. The eight 0 75
7h 77
7s
J . Tarradellas and L. Bonnetain, Bull. Soc. chirn. Frunce, 1973. 1903. Ci. Mairesse, P. Barbier, and J. Huebel, Bull. SOC. chim. France, 1974, 1297. F. Chatelut and C. Eyraud, Bull. SOC. chim. France, 1973, 2646. A. T. Pilipenko, L. L. Shevchenko, R. I. Sukhomlin, V. L. Ryzhenko, and M. S. Ostrovskaya, Zhur. obshchei Khim., 1974, 44, 997.
85
Elements of Group 11
Figure 9 Environment of the calcium ion in the hydrated galactose-calcium bromide complex (Reproduced by permission from J. Arner. Chem. SOC., 1973, 95, 6442) atoms form a distorted square-antiprismatic shell round the Ca2+ion, with the Ca-0 distances W(l) 2.390; W(2) 2.352; W(3) 2.446; 0 - 1 = 0 - 3 , 2.495; 0 - 2 , 2.504; 0 - 4 , 2.552, and 0 - 5 , 2.460A. The closest Ca-Br contact is 4.5A, which is 1.5A longer than the sum of the bromide and calcium ionic radii.79 The crystal structures of his@ -D-fructopyranose)-calcium chloride trihydrate, 2C,H,,O,,CaClZ,3H,O, and p-' D-fructopyranose-calcium chloride dihydrate have been determined from X-ray diffraction data on single crystals. The compounds possess space group Cz, P21, with a = 16.631, 7.85, b = 7.847, 11.68, c = 10.886, 7.07 A, p= 127.8, 94.5", d(obs) = 1.61, 1.65, d(ca1c) = 1.61, 1.68 for 2 = 2, respectively. In the former, carbohydrate chains are separated by sheets of Ca, C1, and HzO entities. In the latter, co-ordination around Ca is by seven 0 atoms in a pentagonal bipyramid. Hydroxy-groups of fructose occupy the equatorial positions and water molecules are at the The structure of myo-inositol-calcium bromide pentahydrate, C,Hl,0,,CaBr,,5Hz0, is triclinic, with space group P i and lattice parameters a = 7.513, b = 8.280, c = 15.035 A, a = 70.43", p = 82.06", y = 68.08", d(obs) = 1.90, d(ca1c) = 1.910 for 2 = 2. The structural formula for the compound is shown in (7). H
OH
OH OH CaBr, SH,O (7) 79 80
81
W. J. Cook and C. E. Bugg, J. Amer. Chem. SOC., 1973, 95, 6442. D. C . Craig, N. C. Stephenson, and J. D. Stevens, Cryst. Struct. Comm., 1974, 3, 195. D. C . Craig, N. C. Stephenson, and J. D. Stevens, C r y s t . Struct. Comm., 1974, 3, 277.
86 Inorganic Chemistry of the Main -group Elements The calcium ion is bound to four water molecules and two symmetryrelated myo-inositol molecules, as shown in Figure 10. O n e myo-inositol molecule is attached through its 0 - 2 and 0 - 3 hydroxy-groups, and the second is co-ordinated through its 0 - 5 and 0-6 hydroxy-groups. Together with the water molecules W(2), W(3), W(4), and W(5), these constitute a
Figure 10 Environment of the calcium ion in myo-inositol-calcium bromide pentahydrate (Reproduced by permission from Acta Cryst., 1973, B29, 2404) distorted square antiprism about the Ca2’ ion at distances apart of: 0-2, 2.502; 0 - 3 , 2.459; 0 - 5 , 2.480; 0-6, 2.520; W(2), 2.416; W(3), 2.370; W(4), 2.410, and W(5), 2.439 A. The Ca-0 distances and co-ordination of the metal are in agreement with those found for other sugar-calcium halide complexes and several calcium salts of sugar acids. T h e Br- ions are hydrogen-bonded t o H 2 0 molecules and to hydroxy-groups. There are no direct Ca-Br contacts (the shortest Ca-Br distance is 4.5 A) but several HzO molecules form bridges between the calcium and bromide ions.” Alkaline-earth-metal iodides also form complexes with dimethyl sulphoxide. The complexes Ca12,7Me2S0,Sr12,2Me2S0, and Ba12,8Me2S0 were isolated from solutions of the alkaline-earth-metal iodides in DMSO. The i.r. data bond, attributed to co-ordination of indicate the presence of a M-0 Me,SO to the 4 Strontium
The Sr-A1 phase diagram has been investigated and the vapour pressures of the compounds SrA1, and SrA1, which occur in the system have been determined by the Knudsen effusion method. The phase diagram shows two
’’ W. J. Cook and C. E. Bugg, Hi
Acta Cryst., 1973, B29, 2404. E. Ya. Gorenbein and T. D. Zaika, Zhur. neorg. Khim., 1973, 18, 2279.
Elements of Group I1
87
eutectics, one between A1 and SrA1, at 630 "C and 3.2 mol YO Sr, and one between Sr and SrAl, at 560 "C and 70 mol YO Sr.84Phase relationships in the Sr and Hg system have been studied by thermal and X-ray methods. The compounds SrHg and SrHg, melt congruently at 850 and 772 "C. Eight other compounds form by peritectic reactions: Sr,Hg, 458; Sr,Hg, 478, Sr,Hg,, 545; SrHg,, 512; SrHg36, 481; Sr,Hg,, ca. 427; SrHg,,, 289; and SrHg, (x = ca. 13,62 "C. Eutectics occur at 82.0 moi OO/ Sr (442 "C)and at 40.5 mol%- Sr (694°C). The crystal structures of all the compounds except Sr,Hg and SrHg, have been determined.85 A new hydrated crystalline strontium tetragermanate, SrGe409,2H20,has been isolated from the SrO-Ge0,-H,O system at 25 "C in addition to the known SrH,GeO,. The X-ray pattern of SrGe40,,2H,0 is similar to that of SrGe,O,, previously prepared from SrCO, and Ge02.86 The azides Sr(N,),,6H20 and Sr(N,),,4H20 can be prepared by crystallization from saturated aqueous solutions at -9 and 9 "C, respectively. These compounds are monoclinic, with a = 6.236, 6.355; b = 6.087, 6.196; c = 6.236, 6.355 A; p = 115.12, 119.15"; d(obs) = 2.06, 1.97; d(ca1c) = 2.16, 1.96 for 2 = 1, 8, respectively. The X-ray diffraction patterns differ considThe reaction of strontium with nitrogen erably from that of Sr(N3)z,2Hz0.M7 might be expected to result in the formation of Sr,N,, but in such reactions, even up to 900"C, this nitride was not detected. The products found were Sr,N, SrN, and another phase which was considered to be a mixture or solid solution of SrN and Sr,N. This mixture gives ammonia, nitrogen, hydrogen, and hydrazine on hydrolysis.8*The compound Sr,B2N, has been prepared by heating compressed tablets of Sr,N, and BN mixtures in sealed silica tubes at 950°C. The strontium boride nitride reacted with oxygen at 700°C to form Sr,B,O,. These compounds were characterized by i.r. spectra, X-ray diffraction, and chemical analysis. For Sr,B2N4,the absorption bands of the ' polyphosphide SrP, [BN,I3- ions are observed at 1660 and 580 ~ m - ' . ~The crystallizes in the monoclinic space group C2/m, with a = 11.432, b = 7.387, c = 8.561 A, p = 103.45", and Z = 8. The black compound can be prepared by heating the elements in the presence of sulphur for 2 h at 1150 "C. The polyphosphide Ba3PI4is isotypic with Sr3PI4and has space group P2,la, with a = 11.997, b = 12.990, c = 6.516 A, p = 123.40", and
z= 2."O
The reaction of ozone with strontium peroxide prepared in Freon 12 below 0 "C is reported to produce strontium ozonide, Sr(O,),, and strontium superoxide, Sr(Oz)z.The ozonide forms only below -70°C and neither 84
86 87
" 89
yo
B. P. Burylev, A. V. Vakhobov, and T. D. Dzhuraev, Doklady Akad. Nauk. Tadzh. S.S.R., 1974, 17, 35. G. Bruzzone and F. Merlo, J, Less-Common Metals, 1974. 35, 153. E. A. Knyazev, A. N. Akulov, and A. G. Tarasenko, Zhur. neorg. Khim., 1973, 18, 3146. H. Krischner and H. E. Roth, 2. Krist., 1973, 137, 311. J. Gaude and J. Lang, Rev. Chim. minbrale, 1972, 9, 799. J. Gaude and J. Lang, Rev. Chim. mine'rale, 1974, 11, 80. W.Dahlmann and H. G. Von Schnering, Naturwiss., 1973, 60, 429.
88
Inorganic Chemistry of the Main -group Elements
compound appears above -20 0C.91The electron affinities of SrSe, SrTe, Case, and CaTe have been determined from the temperature dependences of the electrical conductivity and the thermionic emission. By using these values together with previously determined values for BaO, Bas, Base, BaTe, and CaO and a correlation with the lattice spacings, estimates of the electron affinities of other chalcogenides have been obtained by extrapolation. All values are shown in Table 2; extrapolated values are in parenthesis,
Table 2 Electron aflnitiesleV of the Group 11 metal chalcogenides Mg Ca Sr Ba
0 (0.85) 0.70 (0.64) 0.57
S (3.15) (1.85) (1.35) 0.84
Se (4.50) 2.32 1.77 0.9.5
Te -
3.53 2.40 1.43
and MgTe has the wurtzite structure and hence is not included. The electron affinity of a solid is defined as the difference between the surface potential (vacuum level) and the bottom of the conduction band at the surface. The electron affinity of the Group I1 metal chalcogenides decreases as the size of the cation increases from Mg to Ba. This is expected since increasing the size of the cation weakens the strength of the positive ion-negative ion dipole layer at the crystal surface, while increasing the size of the anion strengthens the dipole layer.92 The equilibrium dissociation pressure of strontium sulphate, SrSO,, has been measured by the torsioneffusion method from 1370 to 1540 K. The total pressure for the reaction:
The enthalpy and entropy of vaporization are 127.4 kcal mol-1 and 5 8.5 e.u., re~pectively.~~ The molecular structure of the triethanolamine complex of strontium nitrate, [N(CH,CH20H),]2Sr(N03)2,has been determined by single-crystal X-ray diffraction. In this compound strontium is co-ordinated by the eight heteroatoms of the two triethanolamine ligands in an approximately cubic polyhedron. This is shown in Figure 11. The strontium ion is isolated from the nitrate ions by this cage of six oxygen atoms at Sr-0 distances ranging from 2.534 to 2.594 A, and two N atoms at Sr-N distances 2.830 A. The nitrate ions are linked with the OH groups of the triethanolamine ligands by strong hydrogen bonds. Crystals are monoclinic, space group C 2 / c , with a = 17.972, b = 8.662, c = 14.112 A, p = 104.5", and Z = 4.94The systems 91
92
91 94
I. I. Vol'nov, S. A. Tokareva, G. P. Pilipenko, V. 1. Klimanov, and V. N. Belevskii, Izuest. Akad. Nauk S.S.S.R., Ser. khim., 1973, 2183. K. V. Tsou and E. B. Hensley, J. Appl. Phys., 1974, 45, 47. L. M. Fuke, Report 1973, LBL-1832. J . C. Voegele, J. Fischer, and R. Weiss, Acta Cryst., 1974, B30, 66.
89
Elements of Group I1
Figure 11 Co-ordination of Sr in the triethanolamine complex of strontium nitrate (Reproduced by permission from Acta Cryst., 1974, B30, 66) Sr(BW),-LiBH,-THF and Ba(BH,),-LiBK-THF have been studied at 20°C. In the first system the phase Sr(BH4),,2THF was detected. Both Ba(BW),,2THF and Ba(BH,),,THF complexes were found in the second system.95 5 Barium
The vapour pressure of metallic barium has been determined, and over the temperature range 983-1408 K is given by log(P/Torr)= 7219- (8.025 K/T) 95
V. I. Mikheeva, L. N. Tolmacheva, and A: S. Sizareva, Zhur. neorg. Khim., 1974,19, 1140.
90
Inorganic Chemistry of the Main -group Elements
Using these data and the third law of thermodynamics, the enthalpy of sublimation of barium at 0 K is calculated to be 42 kcal m01-l.~~ The partial and integral molar enthalpies of formation of liquid solutions of Ba and Si have been derived. At 1723°C the enthalpies of formation of the liquid compounds BaSi, BaSi,, and BaSi, are 48.9, 51.2, and 46.0 kJ mol-', respectively." Crystals of Ba,Ge are prepared from the elements at 1200 "C. These are orthorhombic, space group Pnma-D:;, with a = 8.38, b = 5.48, c = 10.04 and Z = 4. The structure is of the anti-PbC1, type.98 The compound Ba,Bi crystallizes in the space group I4/mmm, with a = 5.263, c = 18.700 A, d(ca1c) = 6.20 for Z = 4. These data agree with previously reported results. The compound is isomorphous with Sr,Sb, (see these Reports, Vol. 2, p. 93), and consists of layers of Ba(l), layers of Ba(2), and Bi atoms, forming a close-packed sheet. The Ba(1) atoms have twelve neighbours, 4Bi, 4Ba(l), and 4Ba(2), at distances of 3.668, 3.772, and 4.173 A, respectively. The Ba(2) atoms have nine neighbours, lBi, 4Bi, and 4Ba(l) atoms, at 3.556, 3.784, and 4.173 respectively. Each Bi atom is surrounded by nine barium atoms, forming the unit BiBa,, similar to the SbSr, units in Sr,Sb. The Ba(1)-Ba(1) distance of 3.722A is shorter than the minimum distance of 4.34 A in metallic barium and probably indicates some ionic character of the Structural data have been obtained for the compounds BaMg2M2(M = Si, Ge, Sn, or Pb). These compounds were prepared from the elements. The space groups of BaMg,Si, and BaMg,Ge, are I4/mmm-D;; and those of BaMg,Sn, and BaMg,Pb, are P4/nmm-D:;. For X=Si, Ge, Sn, and Pb, a = 4 . 6 5 , 4.67, 4.89, 5.00; c = 11.09, 11.33, 24.20, 12.11 A;d(expt)=3.27, 4.35, 4.90, 6.60; d(calc)=3.36, 4.45, 4.88, and 6.59, respectively. BaMg,Sn, has Z = 4 ; the other compounds have Z = 2 . BaMg,Si, and BaMgzGezcrystallize with the ThCr,Si,-type of structure whereas BaMg,Sn, and BaMg,Pb, show two new atomic arrangements which are layer variants of this structure."" Barium tetrahydroborate, Ba(BH,),, has been synthesized by the exchange reaction of Bar, with excess LiBH, in THF. The compound is precipitated by addition of ether and melts at 385 "C with little decomposition.'" In studies of alkaline-earth oxogallates and oxothallates, it has been found that the differences between the sub- and super-structure of BaGa,O, concern connections of the GaO, tetrahedra and distortions of the oxygen polyhedra around Ba, and that Ba,T1,0, has space group D:E-Pcmn, with
A,
A,
96
M. P. Parshina and P. V. Kovtunenko, Zhur. fiz. Khim., 1974, 48, 483. Yu. 0. Esin, V. M. Sandakov, P. V. Gel'd, M. A. Ryss, A. K. Golev, and V. P. Zaiko. Zhur. priklad. Khim., 1973, 46, 2402. '* K. Turban and H. Schaefer, Z . Naturforsch., 1973, 28b, 220. 99 M. Martinez-Ripoll, A. Haase, and G. Brauer, Acta Cryst., 1974, B30, 2203. InnB. Eisenmann and H. Schaefer, Z . anorg. Chem., 1974, 403, 163. ''I V. 1. Mikheeva and I. N. Tolmacheva, Zhur. neorg. Khim., 1974, 19, 1222. 97
Elements of Group I1
91
a = 6.264, b = 17.258, and c = 6.05 A. Ba,Tl,O, is isotypic with Ca,Fez05.102*103 The high-temperature crystal structure of barium silicate, BaSi,O,,, has been determined by X-ray methods. At high temperatures the compound crystallizes monoclinically, with space group C2/c, a = 23.202, b = 4.661, c = 13.614 A, p = 97.54", and Z = 6. The structure contains Si,O,, double layers, as in the low-temperature modification, but there is a slightly smaller degree of corrugation of these layers due to the increase in effective ion size caused by extended thermal motion. There are two crystallographically non-equivalent Ba2' ions in the structure which are surrounded by 8 + 2 and 9 + 1 oxygen atoms, re~pecfively.'~~ Crystals of barium thiosilicate, BaSiS,, are orthorhombic, space group Pnma, with a = 8 . 9 3 , b=6.78, and c = 12.01 A.105 The thermal degradation of barium azide under a liquid organic phase is reported to result in the formation of barium pernitride. The exact composition of this decomposition product could not be determined but the compound was either non-stoicheiometric Ba,N, or a mixture of this with Ba3Nz. Contrary to earlier reports, the hydrocarbon medium is seriously degraded, resulting in the formation of BaH, and Ba(HC2),.lo6Hydrated barium azide, Ba(N3),,Hz0,is monoclinic, with space group Cc-C:, a = 7.29, b = 10.84, c = 6.96 A, p = 104"42', and Z = 4. Each Ba atom is surrounded by seven terminal N atoms and two water molecules in the form of a distorted triangular prism, with three more atoms above the centres of each of three faces of the prism. The azide ions are linear and symmetrical, with average N-N distance 1.173 &Io7 The structures of the polysulphides Bas,, Bas2, SrS,, and SrS, have been investigated. The reaction of Bas with S at 550°C produces Bas3 single crystals of space group P42,m, with a = 6.881, c = 4.177 A, and Z = 2. The reaction of Sr(OH), with S at 200 "C under nitrogen produces orthorhombic SrS, prisms of space group B2cb, with a = 7.088, b = 0.982, c = 8.032 A, and Z = 4 . The thermal decomposition of Bas, at 600°C produces monoclinic Bas,, of space group C2/c, with a = 9 . 3 4 7 , b=4.761, c=9.O5OA, p = 118.41", and Z = 4 . Thermal decomposition of SrS, at 300°C produces tetragonal SrS,, of space group 14/mcm, with a = 6.098, c = 7.646 A, and z= 4.108 The structures of a series of barium compounds Ba,CdS,, Ba,CdSe,, BaCdS,, BaCu,S, and BaCu,Se, have been determined in which barium is seven-co-ordinate. Ba2CdS, and Ba,CdSe, are isostructural, space group Pnma, and Z = 4 with a = 8.915, b = 4.336, c = 17.244 A for the former
'04
H. J. Deiseroth and H. Muller-Buschbaum, 1 Inorg. Nuclear Chem., 1973, 35, 3177 R. Von Schenck and H. Muller-Buschbaum, 2.nnorg. Chem., 1974, 405, 197. H. Katscher, G. Bissert, and F. Liebau, Z . Krist., 1973, 137, 146, J. T. Lemley, Acta Cryst., 1974, B30, 549. S. Salot and J. C. Warf, Inorg. Chem., 1974, 13, 1776. E. M. Walitzi and H. Krischner, Z . Krist., 1973, 137, 368. H.G . Von Schnering and Ngoh-Khang Goh, Naturwiss., 1974, 61, 272.
92
Inorganic Chemistry of the Main-group Elements compound and a = 9.225, b = 4.482, and c = 17.871 8, for the latter. These compounds are also isostructural with the previously reported Mn analogues and with K,AgI,. Cadmium ions are in a tetrahedral environment and the tetrahedra form infinite linear chains by corner sharing. The Ba2+ions are in seven-fold co-ordination in which six anions form a trigonal prism and one anion caps one of the rectangular faces. This geometry persists in the compound BaCdS,, which has space group Pnma, a = 7.278, b = 4.167, c = 13.919 A, 2 = 4,and which is isostructural with BaCdO,. The analogous BaCdSe, could not be prepared. Barium ions are in the usual seven-fold, capped hexagonal prism, co-ordination in BaCu,S2 and BaCu2Se,, which are also isostructural, with space group Pnma, Z = 4, and a = 9.308, b = 4.061, c = 10.408 A for the sulphide and a = 9.594, b = 4.214, c = 10.775 8, for the selenide. However, nine Cu ions can also be considered to form a trigonal prism, with all rectangular faces capped, around Ba, since Ba-Cu distances range from 3.24 to 3.54 8, for the sulphide and from 3.37 to 3.67 8, for the selenide.lo9 A study of the system BaC1,-MeOH-Ba(OMe), has revealed two compounds, Ba(OMe),,MeOH and ClBaOMe, the latter separating from solution as large blue crystals.ll" The crystal structure of barium oxalate monohydrate has been determined. The compound BaC204,Hz0is monoclinic with space group C2/rn, a = 10.10, b = 7.96, c = 6.83 A, p = 121"58', d(obs) = 3.40, and d(ca1c) = 3.43 for 2 = 4.l" The compounds Ba(MeCOS)3,3H,0 and M(MeCOS)(MeCO,),xH,O (M = Ca, x = 3; M = Sr, x = 4) have been prepared by the reaction of MeCOSH with the alkaline-earth carbonates in aqueous solution. The metal acetate thioacetates M(MeCOS)(MeCO,),xH,O crystallized in the monoclinic system. For M = Ca, a = 6.75, b = 15.44, c = 11.34 A, = 113"14', d(obs) = 1.44, d(ca1c) = 1.4 for Z = 4. For M = Sr, a = 12.72, b = 7.095, c = 12.97 A, p = 111"8', d(obs) = 1.86, d(ca1c) = 1.78 for Z = 4. The thermal decomposition of these compounds under nitrogen is as follows: Ba(TAc),,3H20 SrAcTAc,4H20
-
Ba(TAc),,H,O
-
SrAcTAc, 1SH,O
Bas
Ba(TAc),
a SrAcTAc,H,O 180°C
.L
mSr(Ac),( 1- m)SrS
SrAcTAc
I
480 "C
mSrCO,(l- m)SrS log 110
111
J . E. Iglesias, K . E. Pachali, and H. Steinfink, J. Solid State Chem., 1974, 9, 6. E. P. Turevskaya, N. Ya. Turova, and A . V. Novoselova. Doklady Akad. Nauk S.S.S.R., 1973, 212, 1346. J. C. Mutin, A . Aubry, G. Bertrand, E. Joly, and J. Protas. Compt. rend., 1974, 278, C, 1001.
Elements of Group I1 CaAcTAc73H,0
CaAcTAc,H,O
-
93
CaAcTAc,OSH,O
I
1R O T
(1 - rn)CaSrnCa(Ac),
a CaAcTAc
450'C
where Ac = CH,CO; and TAc = CH,COS-.l12 The structure of barium 2-0sulphonato-L-ascorbate dihydrate, Ba(C6H609S),2H20, has been determined from three-dimensional X-ray diffraction data. This sulphate derivative of ascorbic acid (vitamin C) crystallizes in a triclinic cell, space group P1. Cell parameters are a = 5.201, b = 6.951, c = 8.732 A, a = 99.54", 0 = 93.29", and y=lO9", d(obs)=2.44, d(calc)=2.43 for Z = 1 . All but two of the oxygen atoms of the anion (8) are engaged in Ba" co-ordination. These are
HO'CHZCHCHCCOSO, OH
0
(8)
marked 0'. One water molecule is co-ordinated twice, so that each Ba2' is surrounded by ten oxygen atoms belonging to three water molecules and three sulphatoascorbate anions. The Ba-0 distances lie between 2.757 and 3.065 The crystal structure of the triethanolamine complex of barium acetate, [N(CH,CH,0H)3]2,Ba(MeC02)z,has been determined. The structure is made up of complex cations, [N(CH2CH,OH),BaO2CMe]', and acetate ions, MeCO;. As in the triethanolamine complex of Sr(N0,)2 mentioned above, the alkaline-earth-metal atom is held in a cage comprising the eight oxygen and nitrogen heteroatoms of the two tripod ligands (9) but
,,.& & O' c 3( L
O
C6
0'3
3
C '6
(9) 'I2 '13
M. A. Bernard, M. M. Borel, and M. A. Ledesert, Bull SOC. chim. France, 1973, 2194. B. W. McClelland, Acta Cryst., 1974, B30, 178.
94
Inorganic Chemistry of the Main -group Elements OA 1
N
N'
Figure 12 The environment of Ba in the triethanolamine complex of barium acetate (Reproduced by permission from Acta Cryst., 1974, B30, 70) in addition is linked to the O(A1) atom of one of the acetate groups, giving overall nine-co-ordination as shown in Figure 12. Barium-oxygen(1igand) distances range from 2.743 to 2.803& Ba-N distances are 3.025 and distance is 3.108A for N and N', respectively, and the Ba-O(acetate) 2.726 A. The crystals are triclinic, space group Pi, with a = 11.915, b = 10.317, c = 11.223 A, Q = 118.59", p = 98.57", y = 91.98", and Z = 2."" I14
J . C . Boegel, J. C . Thierry, and R. Weiss, Actu Cryst., 1974, B30, 70
3 Elements of Group 111 BY G. DAVIDSON
1 Boron General.-An extensive series of chemical and physical measurements of p -rhombohedra1 boron has been reported (density, lattice constants, microhardness, thermal expansion, electrical resistivity, melting point). The melting point was found to be 2365 K.' The determination of boron in silicon .may be achieved by separating the B by fusion with Na,O,-Na,CO,, followed by conversion of the B into boric acid, which may be determined by potentiometric titration.* A high-resolution n.m.r. spectrometer has been developed for the determination of reliable "B chemical shifts in solids containing tetrahedrally co-ordinated b o r ~ n The . ~ data reported are summarized in Table 1. Table 1 "B chemical shifts for tetrahedrally co-ordinated boron Compound NaBH, KBF, Me,NBCl, [PCI, Br,-,]'BCl, PBr,B Br, Et,NBBr, Et,PBI, Na,B,O,. I OH,O BPO4 BP
S"B/p.p.m. from B(OMe), 64* 1.5 18 11 10* 1 42.3 * 1 52.5 f 1 135.2+0.5 11k.3 32.4* 1 6713
Cragg and Weston have written an extensive review of the mass spectra j f boron compounds of all types." A report has been made of "B and '"N n.m.r. data for a wide range of B-N compounds containing four-co-ordinate b o r ~ n Similar .~ data have also been given for B-N, B-C, B-0, and B-S compounds with three-co-ordinate boron.6
'
C. E. Holcombe. D. D. Smith, J . D. Lore. W. K. Duerksen. a n d D. A. Carpenter, High Temp. Sci.. 1973, 5, 349. ' M. Taddia and M. 7'. Lipolis, Ann. Chim. (Italy), 1973. 63, 131. ' K. B. Dillon and T. C. Waddington, Spectrochim. Acta, 1974, 30A, 1873. R. H.Cragg and A. F. Weston, J. Organometallic Chem., 1974, 67, 161. N. Niith and B. Wrackrneyer, Chem. Ber.. 1974, 107, 3070. H. Noth and B. Wrackrncyer, Chem. Ber., 1974, 107, 3089.
95
96 Inorganic Chemistry of the Main-group Elements In a long and thorough review of the photoelectron spectra of a large number of non-metal compounds, attention is drawn to their ready interpretation by MO models. Topics such as electron-deficiency (of particular interest in the context of boron compounds), 0-and .rr-interaction, and electron-pair delocalization are also considered.'
Boranes.-Ab initio MO calculations, using a restricted Hartree-Fock scheme, on the postulated radical HBF yield values for the optimal geometry which depend upon the nature of the gaussian basis sets.' Three possibilities are: r(H-B) = 2.60 a.u., r(B-F) = 2.45 a.u., L H B F = 122"; 2.53, 2.61, 121"; or 2.25, 2.50, 121". SCF calculations of the MO's in the system: 2BH, F B,H, suggest that a symmetric (C,,,) approach of two BH, units is preferred to an unsymmetric ( C , ) one, with formation of only one H-bridge. The transition state has been calculated to be 2.6 kcal mol-' (of B&) higher than 2BH3, with two equivalent unsymmetrical B - .H-B bridges (B-B distance 3.0 All four possible borane adducts of hexamethylenetetramine have been isolated: (CH,),N,,nBH, ( n = 1, 2, 3 or 4).'" Some i.r. and n.m.r. spectral data have been listed for all of them. An ab initio MO calculation has been carried out on B,H,." If it is regarded as being an interacting system of two BH, units, the charge density in the region between these could be calculated within the framework of configuration analysis. The charge-transfer interaction was found to be the most significant for the proper description of the bridged three-centre bonds in B,H,. The Raman spectrum of B,H, has yielded values for the u = O + 2, 1 -+ 3, and 2 + 4 ring-puckering vibrational transitions at 753.7, 776.1, and 795.6 cm-', respectively (for 'lB2H6)." The thermal decomposition of B,H, was found to have a reaction order of 3/2 in diborane concentration. The Arrhenius parameters (probably too low) are: *
log(A/cm"* moll'* s-') = 4.72 k0.14 E, = 42.47 f 1.17 kJ mo1-l
The reaction was truly homogeneous, since neither coating nor changes in surface: volume ratio altered the rate ~ 0 n s t a n t . l ~
'
H. Bock and H. CJ. Ramsey, Angew. C h e m . Inmnnt. E d n . , 1973. 12, 731. A. Brotchie and C. Thomson. Chem. Phys. Letters. IY73. 22, 338. 1. M. Pepperberg, and W. N . Lipscomb. J . Anier. C h r m . Soc.. 1974. 96, 1315 M. D. Rilcy and N. E. Miller. Inorg. Chem.. 1974. 13, 7 0 7 . S . Yamabe, '1'. Minato, H . Fujimoto, and K. Fukui, Theor. C h i m . Actu, 1974. 32, 187. L. A. Carreira. J. D. Odom, and J . R. Durig, J. C h e m . Phys., 1973, 59, 4 Y S 5 . [ I . Fernandez. J . Crrotewold. and C. M. Previtali, .I.C'.S. Dalton, 1973, 2090.
' D.
' 11. A. Dixon. I" ' I I' ' I
Elements of Group 111 97 The reaction of 0 atoms with BZH6 may be studied in a discharge-flow reactor using a time-of-flight mass spectrometer as detector.14 In the presence of excess 0 atoms, the rate constant for the disappearance of B&6 is k, = (4.2 k2.7) x lo'' cm3molecule-' s-' at room temperature, with the activation energy 4.8 f0.5 kcal mol-'. If excess B,H6 is present, the reaction is faster, and gives rise to chemiluminescence [from BO, A(2II)+ X(,Z), u ' = s S ] . These data have been interpreted in terms of a chain mechanism:
0 + B2H6 + B H 3 0+ BH,
(initiator)
BH,+O+ OH+BH2 O H + B,H6 + H,O
+ BH, + BH,
I
(propagators)
When 0 atoms are in excess, BZH6 disappearance is controlled by the first reaction, while 0 atoms are removed, thus: O+B,H6+BH,+BH,0 BH,O+ 0 + BH,+ 0, 2FH,
-+
B&
Unlike Me,SO, R 3 P 0 ( R = M e or Ph) causes a symmetrical cleavage of B2H6, producing mainly R3P0,BH3 (characterized by n.m.r.), with some R3P,BH3 by reduction of the oxide. l5 Trimethylamine N-oxide hydrochloride, with NaBH,, produces the analogous Me,NO,BH,. A direct reaction of amine N-oxides with B2H6 gave violently explosive products, and it has been tentatively suggested that these were the products of unsymmetrical cleavage, e. g. [(R,NO),BH,]'BHi. The ring-puckering vibrations of I.L -NH2B2H5,together with the ND2-, B2D5-, and perdeuteriated derivatives, are at 337.6, 333.6, 244.6, and 243 cm-', respectively.16 Field-ion mass spectra have been reported for B4H10, B5H9,Me3N,B3H,, Me,N,BH,, Me3N,BH2Br, and 1,1,4,4-tetrarnethyl- 1,4-diazonia-2,S-diboratacyclohexane. l 7 Least-squares-fitted monoisotopic mass spectra have been tabulated for B4H10, B,H,Br, BSHsI, B,H,,, EtBlOHl,,and B10H16. Isotope cluster analysis of the spectrum said to be due to B,,H,, shows that it is actually a mixture of C,BlOH,, and C,B,H,,.'8 "B, 13C, and 'H n.m.r. spectra of pentaborane, ethylpentaboranes, and "C-enriched methylpentaboranes have been obtained. Analysis of the chemical-shift data yielded values for the effective electronegativities of the boron atoms in the cage structure-these were found to be consistently l4 I'
'' "
'*
C . W. Hand and L. K. Derr, lnorg. Chem., 1974, 13, 339. R. A. Geanangel, J . Inorg. Nucleur Chrm., 1974. 36, 1397. A. S. Gaylord and W. C. Pringle, J. Chem. Phys., 1973, 59, 4674. L. A. Larsen and D. M. Ritter, Inorg. Chem., 1Y74, 13, 2284. E. McLaughlin, L. H. Hall, and R. W. Rozett, J . Phys. Chrm., 1973, 77, 2984.
Inorganic Chemistry of the Main- group Elements
98
lower for the apical than for the equatorial B atoms.', The resultant charge differences are in good agreement with those indicated by recent MO calculations on these systems. The reaction of BMe, with B,H, (catalysed by GaMe,) produces 2MeB,H, via a route that can be regarded as being formally analogous to a carbene-insertion reaction.20Similar boron-insertion reactions using H,BCIOR, with [Me3MTVB,H,]-(MrVSior Ge) produce l-Me,M'"B,H,, which are the first known examples of apically substituted hexaborane(10) derivatives. Pentaborane(9) reacts with primary amines to give adducts B5H9,3NH2R, with breaking of B-H-B bonds." These adducts decompose at ca. 150-1 80 "C, to N-alkylborazines:
B,H,,3NH2R
-
1 HB N ''
+
(BH), + 5H2
BH
R
The crystal structure of B,H,(PMe,); has been determined, and the resulting molecular structure is shown in Figure 1. The molecule is fluxional, and the "B n.m.r. spectrum is consistent with the scheme shown in formulae (la) and (lb)." C6
4
Figure 1 Structure of R,H,(PMe,)2, showing ellipsoids of thermal motion (Reproduced by permission from J . Amer. Chem. SOC.,1974, 96, 301 3 ) T. Oriak a n d E. Wan, J. Magn. Resonance, 1974. 14, 66. D. F. Gainea, S. Hildehrandt. and J . Ulrnan, Inorg. Chem., 1974, 13, 1217. A. F. Zhigach, V T. Laptev. A. B. Petrunin. V . S . Nikitin. and D. H . Bekkcr. R i m . .1. Inorg C h o n . , 1973. 18, 1080. '*A. V. Fratini, G. W. Sullivan, M. L. Denniston. R. K . Hertz, and S. G. Shore, J. Amer. C'hem. S o c . . 1071. 96, 3013. Iy
Elements of Group 111
99
Variable-temperature '€3 and "€3 n.m.r. spectra of B6HI0,2-MeB6H9, and 2-BrB6H9show that the static structures are found in all cases at temperais in agreement with tures between -1 10 and - 150 0C.23That for X-ray data. The others possess structures containing no mirror-plane. Ambient-temperature spectra involve scrambling of all bridging hydrogens, while those at intermediate temperatures are consistent with the scrambling of only some of these. A b initio SCF calculations have yielded wavefunctions for B,H,,, B,H,,, . ~ ~ have been compared with the results of B&&-, BloH:;, and B I o H : ~These an approximate calculation using the PRDDO (partial retention of diatomic differential overlap) method. The latter was found to give quite satisfactory results, for much less computing time. "B n.m.r. chemical shifts for all possible isomers of monochloro-, monobromo-, and monoiodo-decaborane( 14) have been determined using the "B-"B double-resonance technique." The data for 5-chloro- and 6iodo-decaborane(l4) were reported for the first time. All trends in the chemical shifts are dominated by the influence of the 2p orbital size on the paramagnetic shielding term (up). A study of a large number of "B chemical shifts in monohalogenodecaboranes has provided a good basis for the prediction of chemical shifts in the disubstituted compounds. Thus, if A u A and A u B are the A-shifts in the monohalogenodecaboranes, then the A-shift in the related dihalogenodecaborane, Auc, is given by: AuC= (0.920 *0.019)(A~,+ AuB)- (0.047*0.0049)
The relevant chemical shifts were mostly assigned using the "B-"B doubleresonance technique.26 Localized MO's have been derived for B16H20, using Boy's procedure, from the results of a PRDDO calculation, based on the simpler hydrides *' 24 25
26
V. T. Brice, H. D. Johnson jun., and S. G. Shore, J . Amer. Chem. SOC., 1973, 95, 6629. J . H. Hall jun., D. S. Marynick, and W. N . Lipscomb, J . Amer. Chem. Soc., 1974, 96, 770. R. F. Sprecher, B. E. Aufderheide, G. W. Luther tert., and J . C. Carter, J. Amer. Chem. SOC., 1974, 96, 4404. R. F. Sprecher and B. E. Aufderheide, Inorg. Cheq., 1974, 13, 2287.
100
Inorganic Chemistry of the Main-group Elements
BioH14 and B,H,, as analogues. LMO's from smaller molecules can apparently be transferred to closely related regions of larger m01ecules.~~ Pyrolysis of B,H,,S gives three isomeric forms of (B9H8S)2;one was shown by X-ray crystallography to be the 2,2'-(1-B,H,S)2. "B n.m.r. evidence supported the formulation of the others as 2,6'- and 6,6'(BJW)2.28 Borane Anions and Metallo-derivatives.-Greenwood and Ward have reviewed the synthesis and structures of metalloboranes, with a discussion of metal-boron bonding." i n a review of the mechanisms of homogeneous reductions of inorganic species by tetrahydroborates, Hanzlik was able to compare the mechanism of the redox process proper with the homo- and hetero-geneous oxidation of alkali-metal tetrahydroborate~.~~ The "B and 'H n.m.r. spectra of THF solutions containing LiBH, and LiBD, contain signals due to all of the series BH4-,D; (n=O-4).31 There was evidence for an isotope shift in the "B spectrum-thus the resonance due to BH,D- occurs ca. 0.011 p.p.m. upfield from BH;, and J("B-H) in BH3D- is ca. 0.4 Hz less than in BH,. These are the first observations of an isotope shift in "B n.m.r. spectra. A study of the polymorphism of LiBH, to 45 kbar and 550 "C has revealed the existence of five solid forms, and the phase diagram has been pre~ented.~~ Phase relationships in the LiBK-Et,O-PhMe system were studied at 20 "C (three phases were found:. LiBH,, LiBH,,O.SEt,O, and LiBH,,Et,O) and at 85 "C (only LiBH, is p r e ~ e n t ) . ~ ' The energy levels due to hindered rotation of BH; in the hightemperature phases of NaBH, and KBH, have been ~ a l c u l a t e d .The ~~ torsional frequency was calculated to be 240cm-' (NaBH,) and 224cm-' (KBH4). A re-investigation of the electron diffraction of gaseous beryllium borohydride, BeB,H,, is consistent with a linear heavy-atom skeleton rather than a triangular a~rangement.~' One could interpret the data using BeB-B and B-Be-B models, but the latter was considered to be more plausible. The following values for some geometric parameters were proposed: r(Be-B) 1.790(0.015) A, r(B-H,) 1.303(0.012)A, r(B-H,) 1.16(0.04) A, LH,BH, 117.5(1.2)". "
'*
D. A. Dixon, D. A . Kleier. T. A. Halgren, and W . N. I.ipscomb, J. Amer. Chern. SOC.,1974,
96, 2293.
W. R . Pretzer and R. W. Rudolph, J.C.S. Chem. Comm., 1974, 629. N. N. Greenwood and I . M. Ward, Chem. SOC. Reu.. 1974. 3, 231. '"J . Hanzlik, Chrrn. listy, 1973. 67, 1239. " B. D. James. B . E. Smith, and R. H. Newman, J.C.S. Chem. Comm.. 1974, 294. '' C. W. F. T. Pistorius, Z. phys. Chrrn. (Frankfurt), 1974, 88, 253. 71 K. N. Semenenko. B. M. Bulychev, E. A. Lavut, and 1. A. Shapiro, Vestnik. Moskou. Uniu.. Khim., 1973, 662. 7 4 D. Smith, J. Chern. Phys., 1Y74. 60, 958. is G. Gundersen, L. Hedberg, and K . Hedberg, J. Chrrn. Phys., 1973, 59, 3777.
Elements of Group III
101
Ab initio calculations of the energies of Be(BK), for a wide variety of possible configurations suggest that three of these are very similar in energy, and might co-exist in the vapour phase: (2), (3), and (4). This conclusion
(4)
agrees with the observed complexity of the vapour-phase vibrational spectrum of BeB,H8.36 Sr(BH4),,2THF is produced by the reaction of SrCl, with N a B K in THF. Heating to 180 “C yields the non-solvated compound, which is stable to 410°C. It is soluble in THF and diglyme, but not in diethyl ether or di~xan.~’ The reaction of ZnC1, with NaBH, in Et,O solution gives a crystalline compound NaZn(BH&,Et,O. This has been characterized by X-ray studies and elemental anal~sis.’~ A number of complexes of Bfi- and BH,CN- (B) with Co, Ni, Cu, Pd, and Pt have been prepared, e.g. MBL, and MHBL, (L = phosphine; B = BK- or BH,CN-, n = 2, 3, or 4).391.r. spectral data for some of the BH,CNco-ordinations complexes appear to suggest that both M-N and M-H-B occur. The latter gives a u(B-H) band at 2122 cm-’ in Cu(BH,CN)(PPh,). E.s.r. data for the anion B,H;, and a b initio unrestricted Hartree-Fock calculations, both favour an ethane-like structure of D,, symmetry, rather structure, analogous to that of the parent than the bridged, DZh, Tetra-alkylammonium AlH; salts react with diborane in THF to give the B,H; salt and Al(BH,), or a substituted Al(BH4)7.41 The thermal decomposition of NR: B,H, ( R = H , Me, or Et) has been investigated.” When R = H the principal decomposition products are BN, B, and H,, at 98-100 “C;while when R = Me they are BN, B, H,, and C K , and when R = Et they are BN, B, H,, CH4, and C,H, (both at >200 “C). 76
D. S. Marynick and W. N. Lipscomb, J. Amer. Chem. Soc., 1973, 95, 7244. V. I . Mikheeva and L. N. Tolmacheva, Russ. J . Inorg. Chem., 1973, 18, 899. ’’ N. N. Mal’tseva, N. S. Kedrova, and V. I. Mikheeva, Russ. J . Inorg. Chem., 1973,18, 1054. ” D. G. Holah, A. N . Hughes, B. C. Hui, and K . Wright, Canad. J . Chem., 1974, 52, 2990. 40 T. A. Claxton, R. E. Overill, and M. C. R. Symons, Mol. Phys. 1974, 27, 701. 41 L. V. Titov, V. D. Sasnovskaya, and V. Ya. Rosolovskii, Russ. J. Inorg. Chem., 1973, 18, 1.570. 42 I. S. Antonov, M. A. Pchelkina, V. S. Nikitin, G. A. Egorenko, Z . F. Vinogradova, and A . T. Kurakova, Russ. J. Inorg. Chem., 1973, 18, 321. ”
102
Inorganic Chemistry of the Main- group Elements
Evidence has been presented for the B,Hi ion acting as a bidentate or a terdentate ligand in transition-metal complexes. Thus Mn(CO),Br reacts with Me4" B,H, to give Mn(C0)4(B3H,), characterized by "B and 'H n.m.r. spectra as ( 5 ) . Under U.V.irradiation an equilibrium: (OC),MnB3H,
* (OC),MnB,H,+
CO
is set up. The tricarbonyl species apparently has the structure (6).43
oc
\
/
0 c
I
H'
oc
(5)
B,H, reacts with Fe(CO),, and B,H,, with Fe,(CO),, to produce a stable ferraborane, B,H,Fe(CO),, the spectroscopic properties of which suggest that it has the structure (7)."" The reaction of SiF, with ethereal LiB,H, solution at -78 "C gave mainly 2-SiFsBsHs, with about 1% of the 1-isomer. Physical properties and n.m.r. and i.r. spectral data have been reported for the two isomers.45 1- and 2-BrB,H8 form an oxidative addition product with IrCl(C0)(PMeJ,, uiz. 2-[IrBr,(CO)(PMe,),]B5H8, in which the Ir is linked to the B-2 atom. The nature of the product is independent of the stereochemistry of the initial borane. The final complex was characterized by single-crystal 43 44
45
D. F. Gaines and S. J . Hildebrandt, J. Amer. Chern. Soc., 1974, 96, 5574. N . N . Greenwood, C. G. Savory, G. Ferguson, and W. C. Marsh, J.C.S. Chem. Comm., 1974, 718. A. B. Burg, Inorg. Chern., 1974, 13, 1010.
103
Elements of Group 111
X-ray diffraction: the Ir-B(2) distance was 2.07(1) A, while B(1)B(basa1) distances were in the range 1.64(2)-1.69(2) A, and B(basa1)B(basa1) distances were 1.80(2)-1.91(2) The excited states of B6H2-, B,H;-, B,,H:;, B12H:2, B,Cl,, and BlZC1:; have been calculated, including extensive configuration intera~tion.~' The results confirm the original assignments for the electronic spectrum of B4C14, and agree reasonably with that for B,Hi-. The other species appear to have no accessible states in the near-u.v. region. Some new transition-metal complexes of B ~ H Ihave o been prepared,,* e. g. Fe(C0)5+ p-Fe(C0)4-(B6H10)
Fe,(CO),+
I.r., "B n.m.r., and Mossbauer data for this complex support the formulation of this as an Fe" complex with a metal-B4, B, three-centre, twoelectron bond. The complexes ~ ~ ~ ~ S - P ~ ( B ~ H IRh(B6Hl,),(acac), O)ZC~Z, [Rh(B,H,,),Cl],, and [Ir(B6Hlo)C1], are formulated in a similar manner. A stabilized heptaborane system [NBu,]+[p -Fe(CO),-fi,H,,]- has been prepared by the following route:
+NBulI- + [NBu4]+[p-Fe(CO),-B6H,]- + KI [NBu4]+[p -Fe(CO),-B6H9]-+ iB,H6 -+ [NBu4]+[p -Fe(CO),-B,HI2]K+[p-Fe(CO),-B,H,]-
This novel anion has the structure shown in Figure 2 (average B-Fe distance = 2.20 f0.02 A). The action of HCl upon this produces the related Q
Figure 2 The structure of [p -Fe( CO)4-B,Hl,]p (Reproduced from J.C.S. Chem. Comm., 1974, 604) 4h
47 48
M. R. Churchill, J. J . Hackbarth, A. Davigon, D. D . Traficante, and S. S. Wreford, J. Amer. Chem. SOC.,1974, 96, 4041. D. R. Armstrong, P. G. Perkins, and J. J. P. Stewart, J.C.S. Dalton, 1973, 2277. A. Davison, D. D . Traficante, and S. S. Wreford, J. Amer. Chem. SOC., 1974, 96, 2802.
Inorganic Chemistry of the Main-group Elements 104 neutral species F-F~(CO),-B,H,,. The structure of this is not known, but the Fe(CO), group probably occupies a bridge site.,' An analysis of the 70.6MHz "B n.m.r. spectrum of labelled B,H,,Srevealed that a rearrangement occurs during the formation of the thiaborane from B,,H,,, B9H,,,SEt,, or B9H;z.'" Electrochemical oxidations of both apical and equatorial isomers of B,,H,12- and B,,H,L- (L = NH3, NMe,, or SMeJ are analogous to those of the unsubstituted B,,H:; ion, and may be summarized in the following equations:
e BloH,L + e2BloHgL -+ BZoH1,L; + H' B,,H,L
B,oH,,L; C BzoH16Lz+ H'
+ 2e-
The Bz0H,,L~and Bz0H,,L~-(from deprotonation of the former) ions and B,,H16L, compounds are similar in their chemistry to the ions B,,H:,, B,,H:;, and B,,H:;. Equatorial substitution gives primarily inductive effects on the rate of the second equation, while apical substitution can lead to a change in the rate-limiting step under conditions of strong electron withdrawal. 51 Both electrolytic and protolytic methods of decomposition of iodobenzenenonahydro-closo-decaborate(1-), BloH91Ph-, led to the formation Of B ~ o H , I ~ - . ~ ~ Hg(NCS), reacts with 6,9-B,,H1,(SMez)z or 6,9-B10H12(SEt2)2 to give BIOHI3NCS, while this species can also be prepared from NaNCS + B,,,H,,. X-Ray studies show that the structure is as shown in Figure 3. The NCS group is co-ordinated (uia N) to B-6 and the B-N bond distance (1.435 A) is too short for a pure single bond."
Figure 3 The molecular structure and numbering system for B,,H,,NCS (Reproduced by permission from Inorg. Chem., 1973, 12, 2915) 4y
'' " s3
0. Hollander. W. R. Clayton, and S. G. Shore. J.C.S. Chem. Comm., 1974, 604. A. R. Siedle, G. M. Bodner, A. R. Garber, and L. J. Todd, Inorg. Chem., 1974, 13, 1756. A. P. Schmitt and R. L. Middaugh, Inorg. Chem., 1974, 13, 163. R. L . Middaugh, Inorg. Chern., 1974. 13, 744. D.S. Kendall and W. N. Lipscomb, Inorg. Chem., 1973, 12, 2915.
Elements of Group I11
105
A number of new arsaboranes have been prepared from d e ~ a b o r a n e . ~ ~ This reacts with AsCl, in the presence of base and a reducing agent, to give 7-BloHl,As- (the structure proposed on the basis of n.m.r. and other data). This, in turn, yields l,2-BloH1,Asz on further treatment with AsCl,, while the reaction of the latter with piperidine produces 7,8-B9HloAs;. The arsenic atom in the mono-derivative may be quaternized to yield BloH,,AsR, and BloH,, and PhAsC1, react to give BloHllAsPh-. Some new by-products have been isolated from oxidative coupling reactions of BloH:; ‘(which yields chiefly B,,H:;, and B 2 0 H 3 .Thus, the presence of Fe(NO,), gives some B2,H1,NO3-;FeCl, gives 1,6,8-Bl0H7Clf-and 1,6- or 2,6-BloHsC1;.55 A new series of metalloboranes, related structurally to BlOH14, have been bridge reported; they contain B,-ligands bound to metals via two M-H-B bonds and an M-B u -interaction. Their synthesis has been accomplished by treatment of M(CO),Br with K+B9HY4in ethereal solvents (M= Mn or Re), and the following were characterized: 2-THF-6-(CO),-6-MnB,H1,, 5-THF6-(CO),-6-MnB9H,,, 2-Et,0-6-(CO),-6-MnB,H12, and salts of [6-(CO),-6MnB,H,,]- and [6-(C0)3-6-ReBgH,,’]-. The crystal structure of 5-THF-6(CO),-6-MnB,H12 has been determined, and the molecular structure is shown in Figure 4.5h Preliminary X-ray data have been reported for the Rb and Cs dodecahydro-closo-dodecaborates,M,2’ B,,H:;; the compounds are isomorphous Data for the double salts with MCl and belong to the space group Frn3n1.~~ have also been given. A
Figure 4 The structure of 5-THF-6-(CO),-6-MnB,H12 (terminal hydrogens omitted) (Reproduced by permission from Inorg. Chern., 1974, 13, 2261) 54
J . L. Little, S. S. Pao, and K . K. Sugathan, Inorg. Chem., 1973, 13, 1752. Z.B. Curtis, C. Young, R. Dickerson, K. K . Lai. and A. Kaczmarczyk, Inorg. Chem., 1974, 13, 1760. ’5‘7 J . W. Lott and D. F. Gaines, Inorg. Chem., 1974, 13, 2261. S I. Uspenskaya, K. A. Solntsev, and N . T Kuznetsov, J . Struct. Chem., 1973, 14, 140. 55
106 Inorganic Chemistry of the Main - group Elements Some new coupled products have been obtained from the lowtemperature decomposition of hydronium dodecahydrododecaborate(2 - ): H,O++2B1,H:;
H 3 0 ++ 2B,,H?;
and
+ H 2 0+ H, 3 Bz4H2,0H3+ 2H2 --j
B24H:;
Small amounts of B4,H:; were produced, as well as the expected products: B12HloOHz-and B,,Hl,(OH):-.'8 Carbaboranes.-The structure of 2,3,4,5-tetracarbahexaborane, C&H,, has been determined by an analysis of the microwave spectra of ten isotopic species. The short C-C bond lengths (1.43 A) suggest r-bonding character. The molecular dipole moment was found to be 2.21 *0.06 D.s9,"0 The closo-carbaborane 1,6-CzB4H6reacts with NMe, to give S-Me,N+nido-2,4-CzB4H,, which rearranges (thermally or in CHC1,) to give the 3Me,"-isomer. The parent 2,4-CzB4H; ion may be made either by the reaction of NaH with the 3-Me3N+or 5-Me," derivatives, or by the (slow) reaction of NaH or LiH with closo-1,6-CzB4Hs. The reactions are summarized in Figure 5 , the structures proposed being in accord with "B and 'H n.m.r. data." W
Figure 5 (Reproduced from J.C.S. Dalton, 1973, 2 115 ) Variable-temperature "B n.m.r. spectra of the C,Me,B,H; anion are consistent with a previously postulated structure involving removal of one bridging hydrogen from the C,R,B,H, nido -carbaborane structure, i.e. (8). Reactions of the anion with ICl (+ 2-C1C2Me2B,Hs, 3-C1C,Me,B,H5) and Br2(-+3-BrC2Me2B4H5) are believed to proceed via intermediates with 5X
59 "I
''
R. Bechtold and A . Kaczmarczyk. .1. Amer. Chem. Sac.. 1974. 96, 5953 .J. P. Pasinski and R. A. Beaudet, J.C.S. Chrrn. Cornrn.. 1973, (328. J . P. Pasinski and R. A. Beaudet. J . Chem. Phys., 1973, 61, 683. T. Onak, B. Lockman. and G. Haran. J.C.S. Dalton. 1973, 21 15.
Elements of Group III
107
H
(9)
(8)
bridged halogen atoms. The same paper6' also reported an analysis of the 220 MHz 'H n.m.r. spectrum of the parent carbaborane C2MeZB4H6. The species HC(BCl,), and H,C(BCl,), have been suggested as useful precursors in carbaborane Thus, the reaction:
(9) CH,(BCl,), + LiBH, occurred. The new compounds (CF3),PC(CH)B5H5and [(CF,),PC],B,H, are produced by the action of (CF,),PI or (CF,),PCl (in stoicheiometric amounts) on the dilithium derivative of C2B5H7.64 A new nido-carbaborane, CZB~HIO, may be prepared by the gas-phase reaction :
(Yield less than 5%). I.r., n.m.r., and mass spectral data indicate that the most likely structure is as shown in Figure 6, together with estimated bond lengths.65
Y
b
Figure 6 Nido-C,B,H,, (bond distances estimated from ADD theory) (Reproduced by permission from J. Amer. Chem. SOC., 1973, 95, 7514) Octaborane(l2) and,acetylene react in E t 2 0 solution to give a mixture of nido -dicarbanonaborane( 1l), B7C2HI1, and nido-dicarbadecaborane( 12), B,C,H,,. The "B n.m.r. data for the former indicate that this is the first
'' C. G . Savory 63 64
6s
and M. G. H. Wallbridge, J.C.S. Dalton, 1974, 880. D. S. Matteson and P. K. Mattschei, Inorg. Chem., 1973, 12, 2472. L. Maya and A. B. Burg, Inorg. Chem., 1974, 13, 1522. A. J. Gotcher, J. F. Ditter, and R. E. Williams, J. Amer. Chem. SOC., 1973, 95, 7514.
108 Inorganic Chemistry of the Main- group Elements carbaborane containing an integral BH, group, Figure 7. An analogous reaction of B,H,, with but-2-yne gives the mixture B,C2H,Me2+ B,C,H,,Me,. The former seems to possess a different structure from the parent carbaborane, containing 'extra' hydrogen atoms in bridging positions. The B,C2 species have the decaborane geometry, with carbon atoms at the 5 and 6 positions.66A minor product of the second reaction is a new 2,3-isomer of closo-BsC,H,Me,.
Figure 7 A possible structure for B,C,H,, (representing one enantiomorph of a d,l-pair) (Reproduced by permission from J. Arner. Chern. SOC., 1973, 95, 6254) The anion 7,8-C2B9HT2is oxidized by aqueous FeC13 to a weakly acidic nido-carbaborane, 5,6-C2BRH12. This in turn undergoes pyrolytic dehydrogenation at 240°C to give a high yield of a new closo-carbaborane, 1,2-C2B,H,,.67 An improved synthesis of nido -dicarbaoctaborane( 10) has been reported.68 This was carried out in a concentric cylindrical hot-cold reactor of capacity 750 ml. If a 1:2molar mixture of C,B,H, and B,H6 was kept in the reactor for 4 hours, a 35% yield of C,B,Hl, resulted. The reduction of 5,6-C2B8Hl2by Na-Hg in ethanol results in the formation of a new carbaborane, 6,9-C2B8Hl,(isostructural with B,,H:i)."' Reaction with D,O replaced H by D in the two bridging bonds and the axial C--H bonds, while the action of DCI-AICl, brought about deuteriation of the terminal hydrogen atoms at positions 1 and 3. The new closo-carbaboranes 1,2-B,C,H1, and 1,2-B,C2H8Me2are formed by pyrolysing nido-5,6-B,C2H,, and nido-5,6-B,C,H,,Me2, respectively."' The structure of the first species is believed to be that shown in Figure 8, from chemical and spectroscopic evidence. 66
67 68
69 'O
R. R. Rietz and R . Schaeffer, J. Arner. Chem. Soc., 1973. 95, 6254. J . PleSek and S. Heimanek. Coll. Czech. Chem. Comm.. 1974, 39, 821. T. J . Reilly and A. B. Burg, Inorg. Chem., 1974, 13, 1250. B. Stibr, J. PleSek, and S. Heimanek, Coll. Czech. Chem. Comm., 1974, 39, 1805. R. R. Rietz, R. Schaeffer, and E. Walter, J . Organometallic Chem.. 1973, 63, I .
Elements of Group 111 109 10-Acetyl, benzoyl, and formyl derivatives of 1-phenyl-p-carbaborane(8) have been obtained by reactions such as: p-C6H5CB&CLi
+ PhCOCl -+
p-C,H,CB,H,CCOPh
and their further reactions i n ~ e s t i g a t e d . ~ ~ Hetero-organic derivatives of 1-phenyl- 1,lO-dicarba-closo-decaborane( 10) containing bonds between the carbon atoms qnd Main-group elements such
Figure 8 Proposed structure for 1,2-B8C,H,, (Reproduced by permission from J. Organometallic Chem., 1973, 63, 1) as Si, Sn, Pb, P, and As can be synthesized by way of the lithium derivatives of the b ~ r a n e . ~Mercury ’ and methylmercyry analogues also exist, and a number of reactions have been described. 1,8-(MeC),B,H, is oxidized by sodium periodate in 2M-HCl and benzene while in acetic acid and at 25 “C to give 3-(H0)-1,8-Me2-1,8-B9C2Hs, benzene it yields 3,7-(HO),- 1,8-B9C,H7as the only B-hydroxycarbaborane. The monohydroxy-compound dimerizes on heating with loss of two equivalents of H, giving two ‘B9Cz’polyhedra. These are linked by oxygen bridges at the B(3,3‘) and B(7,7’) positions. In the presence of phenol this pyrolyses to form phenoxy-substituted carbaboranes (MeC),B,H,-,(OPh), when n = 6, 7, or 8. A number of other reactions of 3-(HO)-1,8-Me2-l,8-B9C’H8 were also r e p ~ r t e d . ’ ~ Two examples of heteroatom-containing electron-rich boranes have been reported. Thus: Na2(l,2-B9C,H,,) + PhAsC1, -+B,C,H,,AsPh which is related to BI,C2H:;, the BH being replaced by AsPh”. Similarly, the reaction of CsB,H,, with AsC1, and NMe, in MeCN gives BsH,As2S, 7’ 72
73
L. I. Zakharkin, V . N. Kalinin, and E. G. Rys, J. Gen. Chem. (U.S.S.R.), 1974, 44, 148. L. 1. Zakharkin, V. N. Kalinin, and E. G. Rys, J. Gen. Chem. (U.S.S.R.),1973, 43, 848. G. D. Mercer and F. R. Scholer, Inorg. Chem.. 1974, 13, 2256.
110
Inorganic Chemistry of the Main-group Elements
with a nido-structure related to B,C,H:;. Structures were deduced from mass-spectral and "B n.m.r. data.74 The benzodicarbollide ion (10) and its ( 1,4-dihydrobenzo)-derivative
have been prepared, and they may be reduced to the (2-)-ions, which in turn form rr-complexes with a number of transition metals. Figure 9 shows the structure proposed for the benzodicarbollyl-manganese(1) derivative:" "'Sn Mossbauer data have been reported for 3-Sn-1,2-B9C,H,,: S= 4.67 k 0 . 0 4 mm s-I, AE, = 3.83 +0.004 mm sC1. The isomer shift is consistent with a formal Sn" oxidation state, while the large quadrupole splitting arises from the marked asymmetry of the molecular s t r u c t ~ r e . ~ '
Figure 9 Structure diagram of the dibenzodicarbollylmanganese(I) tricarbony1 ion. The large open circle represents Mn; small open circles represent 0, darkened circles C, half-filled circles CH, and unmarked line junctions BH (Reproduced by permission from Inorg. Chem., 1974, 13, 671) 74
'' 7h
A. R. Siedle and L. J. Todd. J.C.S. Chem. Comm., 1973, 914. D. S. Matteson and R . E. Grunziger jun., Inorg. Chem., 1974, 13, 671. R. W. Rudolph and V. Chowdhry, Inorg. Chem., 1974, 13, 248.
Elements of Group I11 111 The reaction of (3)-1,2- and -1,7-B9C;11:; with Zr" or Hf" acetylacetonates produces (3)-1,2- or - 1,7-B9C,H;, salts of the hydroxyl-bridged cat~( ions [M4(a ~ a c )OH), A novel synthesis of closo - 1,7-BloC2H,2has been achieved by joining two one-carbon carbaborane units together, i.e. by heating 2-B5CH, to 250 "C. Figure 10 shows that this occurs when the two units come together with the bridging hydrogens close to each ~ t h e r . ' ~
O
H
Figure 10 Schematic representation of the fusion of two B5C skeletons to form the 1,7-B& skeleton (Reproduced by permission from lnorg Chern., 1974, 13, 755) The crystal structure of Me," PhCHB,,H,,CPh- has been determined; the ion has C, symmetry (disregarding the Ph ring orientations) and an opened icosahedral structure. One C atom is in the B l o c icosahedral fragment, with the other bridging two borons in the open face of this fragment.79 Thermal rearrangement of 9,12-dichloro-CC'-dimethyl-o -carbaborane at 420 "C gives mainly 5,12-dichloro-CC'-dimethyl-rn-carbaborane,whose molecular structure was determined by X-ray diffraction. This isomer is the only one (of 16 possible isomers) which can be produced from the cuboctahedral intermediate mechanism.80 A detailed X-ray study of the NMe: salt of CC'-dimethylundecahydrodicarba-nido -dodecaborate, Me2B,oC2H;1,has enabled all of the atoms, including hydrogens, to be located accurately (see Figure ll).81The anion possesses C, symmetry, with ten boron and one carbon atoms defining an icosahedral fragment with an open B,C face. The second carbon bridges two boron atoms in this face and is also bound to an exo-CH, and an endo-hydrogen atom. 7'
A. R. Siedle, J . lnorg. Nuclear Chem., 1973, 35, 3429.
'O
H.V. Hart and W. N . Lipscomb, Inorg. Ckem., 1973, 12, 2644.
'' R. R. Rietz and M. F. Hawthorne, Inorg. Chem., 1974, 13, 755. '' E. I. Tolpin and W. N. Lipscomb, Inorg. Chem, 1973, 12, 2257.
''
M. R. Churchill and 9. G . DeBoer, lnorg. Chern., 1973, 12, 2674.
Inorganic Chemistry of the Main-group Elements
112
Figure 11 A general view of the Me2BIoC,H;, anion (Reproduced by permission from Inorg. Chem., 1973, 12, 2674) Variable-temperature 'H n.m.r. studies on 1,2- and 1,7-bis(NN12) reveal dimethylcarbamoy1)-l,2- and 1,7-dicarba-closo-dodecaborane( that rotational isomers are present, and they enable estimates to be made of the enthalpies and entropies of. activation for NMe2 rotation.82 Fluoroalkenyl-o-carbaboranes, e.g. MeCB,,H,,C-CF=CFCl, can be reduced by NaBH4 or LiAlH, to mixtures of the hydrofluoroalken91 derivatives, but the stereospecificity of the reaction varies with the alkenyl group.83Similar reactions occur with m -carbaboranes. The carbaborane nucleus in 1-methyl-2-bromoethyl-o-carbaboraneis broken down on reaction with pyridine, forming two types of (3)-1,2-dicarba-undecaborane derivative. These contain both C-N and B-N bonds. Similar reactions occur with the 9-bromo- and 9,12-dibromo-deri~atives:~~
(R = H, Pr', or Ph; n = 1 or 2). The effectiveness of the catalysts is in the sequence: AlC1, AlBr, > BF,,Et,O > SnCI, >> FeCI,. The reaction occurs for
-
'' c'. H. Bushweller, C . Y. Wang, W. J. Dewkett, W. G. Anderson, S. A . Daniels. and 11. Beall, 83 84
J. Amer. Chem. SOC., 1974, 96, 1589. L. I. Zakharkin and V. N. Lebedev, J . Fluorine Chem., 1973, 3, 237. L. I. Zakharkin and V. S. Kozlova, J. Gen. Chem. ( U . S . S . R . ) ,1973, 43, 1091.
Elements of Group 111
113
0-,m-,
and p-carbaboranes, and always gives a mixture of the n = 1 and n = 2 species.85 The first secondary amine in the carbaborane series, 3,3’-iminodi-ocarbaborane, has been prepared by the following reaction with a catalytic amount of toluene-p-sulphonic acid?
Dilithio-o -carbaborane and aa ’-dibromo-o -xylene react to give dihydronaphthocarbaborane, which forms dibromodihydronaphthocarbaborane on allylic bromination. The reaction of the latter with NaI produces naphthocarbaborane (11).The reactivity of this species shows that there is
little, if any, effective 7r-bonding between the B,,, cage and the carbon ring system.87 Because of their possible aromatic properties, polycyclic derivatives containing the o -carbaborane ring are of particular interest. The carbaborane analogue of phenanthrene has now been synthesized.88Investigation of its properties shows that it is not at all similar to phenanthrene itself. Mass spectra have been reported for the B -[2-(trimethylsilyl)ethyl]-, the BB’-bis[2-(trimethylsilyl)ethyl]-, and the BB’-bis[2-(trichlorosilyl)ethyl]derivatives of o-, m-, and p - c a r b a b o r a n e ~ . ~ ~ Recent experiments show that carbaboranes are stable at 500-600 “C for an hour, but at higher temperatures pyrolysis occurs to give H2, CH,, and an insoluble polymeric residue of approximate composition C,.,H, ’B1,. In the presence of water, decomposition occurs at a lower temperature.” Introduction of phenyl groups on the C atoms of the carbaborane nucleus lowers the thermal stability. V. F. Mironov, V. I. Crigos, S. Ya. Pechurina, A. F. Zhigach, a n d V. N. Siryatskaya, Doklady Chem., 1973, 210, 42 1 . ’‘ L. 1. Zakharkin, V. N. Kalinin, and V. V. Gedymin, J. Gen. Chem. ( U . S . S . R ) ,1974, 44, 678. ’’ D. S. Matteson and R. A. Davies, Inorg. Chem., 1974, 13, 859. xu L. I. Zakharkin, A. V. Kazantsev, a n d B. T. Ermaganbetov, 1. Gen. Chem. (U.S.S.R.), 1974, 44, 220. ’’ V. N. Bochkarev, A. N. Polivanov, V. I . Grigos, and S . Ya. Pechurina, J. Gen. Chem. (U.S.S.R.), 1973, 43, 2393. 90 L. I. Zakharkin, V. N. Kalinin, T. N. Balykova, P. N. Gribkova. a n d V. V. Korshak, J. Gen. Chem. (U.S.S.R.), 1973, 43, 2249. x5
114 Inorganic Chemistry of the Main-group Elements "B n.m.r. spectra of all the isomeric carbaborane(l2) species, their B chloro-derivatives, and the dianions of both the unsubstituted and B chloro-carbaboranes have been measured to obtain further data on the structures of the dianions and the mechanism of their isomerization. The spectra of the dianions differ markedly from those of the mono-anions and the neutral species, indicating substantial redistribution of charge and bonding. Oxidation of the dianions was shown to be the determining step in the formation of o -carbaborane from rn -carbaborane, and of m carbaborane from p-carbaborane." A number of B -derivatives of m -carbaborane have recently been synthesized, an example being the formation of 2-vinyl- m -carbaborane according to the equation: CH,=CHBCl,
+C , B , H : ; - j
rn-HCBloH9(2-CH,=CH)CH
On oxidation with CrO,, the 2-carboxy-derivative is readily obtained, which can be converted with diazomethane into the methoxycarbonyl analogue. The carboxy-compound gives an acid chloride with PCl, and a benzoyl derivative on Friedel-Crafts reaction with benzene.92 A study of quadrupole-induced 'H-'O."B spin decoupling in carbaboranes (e.g. 1,7-dicarba-closo -dodecaborane) has shown that increasing molecular volume very probably leads to lH-lo,llB spin-spin coupling coalescence at increasing temperature^.^^ This is due to increasingly efficient 'O."B nuclear spin relaxation. "B-I'B n.m.r. double-resonance techniques, together with off -resonance proton-decoupling, have enabled all of the chemical shifts ("B) to be assigned in 8-iodo- 1,2-dicarbadodecaborane(12).94 "B n.m.r. data, including heteronuclear double-resonance, "Bd'H}, have been reported for ortho-, meta-, and para-isomers of the 12-carbaboranes and their B -monohalogeno-derivatives.9s Calculated frequences and integrated intensities, with theoretical i.r. spectra, for 0- and rn -dicarba-closo -dodecaboranes and their C-deuteriated derivatives have been reported.96This enabled an interpretation of all the intense bands observed in the spectra to be given. m-Carbaboranes with one or two silyl or disilanoxyl substituents have been investigated by i.r. methods, and the data compared with those for the corresponding silicon compounds without the carbaborane s ~ b s t i t u e n t . ~ ~ "
"
V. 1. Stanko. V. A. Brattsev, Yu. A. Gol'tyapin, V. V. Khrapoc. T. A . Habushkina, and -F. P. Klimova, J . Gen. Chem. (U.S.S.R.). 1974, 44, 319. L. I. Zakharkin, V. N. Kalinin, and V. V. Gcdymin. J. Gen. Chem. (U.S.S.R.), 1977. 43, 1956.
97 y4
" 96
y7
H. Beall, A. T. Elvin. and C . H. Bushwcller, Inorg. Chem., 1974. 13, 2031. B. E. Aufderheide a n d R. F. Sprecher, Inorg. Chern., 1974, 13, 2286. T. A . Babushkina. V. V. Khrapov, S. P. Gubuda, and L. D. Filizova. J . Struct. Chem., 1973, 14, 959. T. P. Klimova, I.. A . Gribov, a n d V. I. Stanko, Optics and Spectroscopy, 1974, 36, 650. N. V. Kozlova, L. P. Dorofeenko. A. I,. Klebanskii, and V. F. Gridina, J. Gen. Chern. (U.S.S.R.), 1974, 44, S54.
Elements of Group III
115
The rates of alkaline cleavage of 0-,m-, and p-carbaboranyltrimethylstannanes in MeOH vary in the sequence: ortho >> meta >parag8 A number of mono- or di-tropenylium-carbaboranes (dicarbahemiousenium and dicarba-ousenium ions), together with some related ‘ousenes’, have been reported (see Figure 12).99There is no evidence for T-interaction between the ring and the cage.
A
Figure 12 Ousene -type compounds: (A)[7,12’]-172-dicarba- hemi-ouseniurn ion (€3) [7,11”]-nido-(3)-172-dicarba-herni-ousene,(C)[7,7, 10ZsX]ousene,and (D)[7,7,121”]-1,7-dicarba-ouseniurn ion. The positions of the ring in (B), and of the second ring in (C) are not known, and are drawn as shown for convenience (Reproduced by permission from Inorg. Chem., 1974, 13, 862) Mass spectrometry can be used to distinguish reliably between the CC’-bishydroxymethyl derivatives of o - and rn -carbaboranes and their diacetates .loo The mutual arrangement of the methyl groups and halogen atoms affects the ‘H n.m.r. spectra of C-methyl- and CC‘-dimethyl-o- and -mcarbaboranes and their B -halogeno-derivatives. lo’ Comparison of data from pyridine and CC1, solutions confirms that the CH groups in 0- and mcarbaboranes can form hydrogen bonds. In aqueous alcohol solutions boric acid forms dinuclear complexes (BKioHi,O, 1)2-.102 YX 95,
I00
lo’
“)’
V . I . Stanko, T. V. Klimova, and I. P. Beletskaya, J. Organometallic Chem., 1973,61, 191. K. M. Harmon, A. B. Harmon, B. C. Thompson, C . L. Spix, T. T. Coburn, D. P. Ryan, and T. Y. Susskind, lnorg. Chem., 1974, 13, 862. A. F. Zhigach, V. T. Laptev, V. N. Bochkarev, A . B . Petrunin, B. P. Parfenov, and A. N. Polivanov, J. Gen. Chem. (U.S.S.R.),1973, 43, 866. L. I . Zakharkin, V. N. Kalinin, V. S. Kozlova, and V. A . Antonovich, J. Gen. Chem. (U.S.S.R.),1973, 43, 844. A. Ya. Putnin’, E. M. Shvarts, and A . F. Ievin’sh, Russ. J. Inorg. Chem., 1973, 18, 792.
116 Inorganic Chemistry of the Main-group Elements Metallo-carbaboranes.-A study of thermal rearrangements of nonicosahedral cobalta-carbaboranes of the general form (q-C5H5)CoC,B,H,+,, where n = 6, 7 , 8, or 10, leads to the following empirical rules concerning the migration of heteroatoms during thermal isomerizations: ( a ) the Co atoms will occupy the vertex of highest polyhedral coordination number and remain there. ( b ) the C atoms will not decrease their mutual separation (c) C atoms will migrate to vertices of lowest polyhedral co-ordination number. Once there, they will migrate only to an alternative low-coordination vertex. (d) C atoms will tend to migrate away from Co, subject to ( b ) and (c).lo3 Evans and Hawthorne have published a paper illustrating further applications of the general polyhedral expansion reactions of metallocarbab0~anes.l'~The preparations of species Cp2C02C,B,H,+2 are here described. One of the proposed structures is shown in Figure 13, based on i.r., n.m.r., and mass spectra.
Figure 13 The proposed structure of (C5H5),Co2C2B,H9 (Reproduced by permission from Inorg. Chem., 1974, 13, 869) 103
to4
D. F. Dustin, W. J . Evans, C. J. Jones, R. J. Wierwma, H. Garg, S. Chan, and M. F. Hawthorne, J. Amer. Chem. SOC., 1974, 96, 3085. W. J. Evans and M. F. Hawthorne, Inorg. Chem., 1974, 13, 869.
Elements of Group I11 117 The isotropic shifts of the "B and 13Cnuclear resonances in paramagnetic metalloboranes, CpM(C2BnHn+,),M(C,B,H,+,), (M = Cr"', Fe"', Ni"', or ~ ~ mode of electron Co", n = 6 , 7, 8, or 9), have been e ~ a 1 u a t e d . lThe delocalization is primarily L to M charge-transfer, except for icosahedral Co", where it is from M to L. The extent of delocalization is small, and largely restricted to the metal bonding face. The magnitudes and directions of the isotropic shifts of the metallocarbaboranes and metallocenes are very similar, implying that the energetics of the M-L interaction are similar. A number of new Fe" and Fe"' metallocarbaboranes have been synthesized, both in solution and in the vapour phase, from nido-C2B4H8and closo-C,B,H,. Thus, treatment of 2,4-C,B,H7 with sodium naphthalide, FeCl,, Na'Cp-, and 0, gives (a-2,4-C,B,H6)-(.rr-2,4-c2B4Hs)Fe"'(Cp). Treatment of this with Na-Hg followed by HC1 produces the FeI' species, e.g. (.rr-2,4-C2B4H6)Fe"(Cp).'06 A gas-phase reaction of 2,3-C2B,H, with Fe(CO), gives (.rr-2,3-C,B4H6)Fe(CO), (12) and (n-2,3-C2B,H,)Fe(CO),,
Fe
oc'~o'co
which is to be the subject of an X-ray study to be reported later. 2,4C,B,H, reacts with Fe(CO), at 280 "C, giving the 2,4-isomer of the former and (r-C,B,H,)Fe(CO),. The crystal structure of the dicarbacyclopentaboranyliron tricarbonyl complex, (C2B3H,)Fe(C0)3,mentioned in the previous Report, is shown in Figure 14.'07This reveals that the carbaboranyl ring is planar. Several metallocarbaboranes of Fe, Co, and Ni have been prepared by the direct reaction of 1,5-CtB3Hs, 1,6-C2B4H6,or 2,4-C2B,H, with organometallic reagents in the gas phase or in solution.'08 No prior cageopening step was necessary. As examples of such reactions, Fe(CO)s or (qC,H,)Co(CO), with C,B,H, gave the six-vertex products (OC),FeC,B3H5 or (q -C5H5)CoC2B3Hs,together with the seven-vertex complexes (OC),Fe,B,H, and (.rr-C,H,)Co,C,B,H,. Similar reactions occurred with C,B4H6 to give primarily seven-vertex species (MC,B,) and with C,B,H, to give
-
'05
106 lo'
R . J. Wiersema and M. F. Hawthorne, J . Amer. Chem. SOC., 1974, 96, 761. L. G . Sneddon, D. C. Beer, and R. N . Grimes, J. Amer. Chem. Soc., 1973, 95, 6623. J.-P. Brennan, R. N. Grimes, R . Schaeffer, and L. G . Sneddon, h o r g . Chem., 1973,12,2266. V. R . Miller, L. Ci. Sneddon, D. C. Beer, and R . N . Grimes, J. Amer. Chem. SOC.,1974, 96, 3090.
118
Inorganic Chemistry of the Main - group Elements
Figure 1 4 Molecular structure of B3C2H,Fe(CO), (Reproduced by permission from Inorg. Chern., 1973,12,2266) eight-vertex complexes (MC,B,). Structures were proposed for the compounds prepared, on the basis of the usual physical methods. A further substantial number of new Co and Ni metallocarbaboranes have been reported by Grimes et al. Thus the reaction of Na'C,B,H; with CoC1, and NaC,H,, followed by exposure to air, water, and acetone, gives (r-2,3-C,B,H6)Co( r -C,H,), (r-2,3-C2B,H7)Co(r-C,H,), and (r-2,3C,B,H5)Co,( r-C5H5),. These complexes may also be obtained by reduction of 2,3-C2B4H8with sodium naphthalide, followed by reaction with CoCl,, Na+C,H;, air, and water-see the reaction scheme in Figure 15. If the reaction sequence is carried out starting from 1,6-C2B,H6, the chief pro(.~~-C,B,H,)CO,(.~~-C~H~)~, and [a-5-(1ducts are (.~~-C,B,H,)CO,(~~-C~H~)~, C,,H,)(r-2,4-C,B4H,)]Co(~-C,H,) (see Figure 16).lo9 The structure of Cs+[(C,H,)Co(CB,H,)]- has been determined by X-ray diffraction. The Co"' atom is sandwiched between the C,H; and CB,Hi moieties, with Cs' ions in general positions. The CoCB, skeleton is almost a tricapped trigonal prism, with 2 borons and one carbon atom in the low-co-ordinate 'cap' positions. The Co is bonded to five boron atoms (average bond distance 2.01 A).'"
"")
'I('
R. N. Grimes, D. C. Beer, L. G. Sneddon. V. R. Miller, and R. Weiss, Inorg. C1hrm., 1974, 13, 1138. K. P. Callahan. C . E. Strouse, A. L. Sims, and M . F. Hawthorne, Inorg. Chem., 1974, 13, 1393.
Elements of Group III
119 1NOH ‘H2
-
No+
Figure 15 Reaction scheme for the synthesis of cobalt rnetallocarbaboranes from 2,3-C2B4H,. Open circles are BH groups, solid circles CH groups (Reproduced by permission from Inorg. Chern., 1974, 13, 1138)
Figure 16 Reaction scheme for the synthesis of cobalt rnetallocarbaboranes from 1,6-C2B4H6 (Reproduced by permission from Inorg. Chern., 1974, 13, 1138)
Inorganic Chemistry of the Main -group Elements 120 Crystals of Ph,PMe' [(B,C,H,)Mn(CO),]- are triclinic, space group Pi."' The manganese is bonded to two carbons (at 2.04 A) and three borons (two at 2.35 A, one at 2.23 A) of the eight-atom carbaborane cage. The structure of 2,6-di-q -cyclopentadienyl-octahydro-1,10-dicarba-2,6has been dicobalta-closo-decaborane, 2,6-(r)-C5H,)-2,6-Co,-1,10-C2B,Hs, deduced from X-ray diffraction. The polyhedral framework is a distorted, bicapped square antiprism, with carbons at the caps and one cobalt in each tropical plane. The cobalt atoms are bonded to each other [2.489(1)A apart], this being the first confirmed metal-metal bond in a bimetallocarbaborane.", A number of thermally induced cobalt-migration reactions in cobaltacarbaboranes have been observed for the first time,113e.g. heating 2,6,1,10(C,H,),Co,C,B,H, to 280 "C produces 2,7, 1,10-(CsH5)2C02C2B6H,. This involves the migration of a cobalt atom from a vertex adjacent to cobalt to a vertex separated from cobalt by one boron atom. When Na'Cp- and FeCl, are added to CpCo"'(C2B,H,), previously reduced by sodium naphthalide, a new heterobimetallocarbaborane (13),
(13) CpCo"'(C,B,H,)Fe"'Cp, is produced. 'Another Co"'/Fe"' carbaborane was produced by the reaction of CpCo"' (C,B,,H,,) with ethanolic KOH in the I l l 'I2 'I'
F. J. Hollander, D. H. Templeton. and A. Zalkin, Inorg. Chrm., 1Y73. 12, 2262. E. L. Hod. C. E. Strouse, and M. F. Hawthorne, Inorg. Chem., 1973, 13, 1388. W. J . Evans, C. J . Jones, B. Stibr, and M . F. Hawthorne, J. Organometallic Chem.. 1973, 60, C27.
Elements of Group
m
121
A
Figure 17 Decomposition of the suggested 1 ,2,8,3,6-(CsH,)3C03C2B7H9 to 1,8,2,3-(CsH,),CoC,B,H, (Reproduced from J.C.S. Chem. Cornm., 1973, 706) presence of FeC1, and C,&, and so two quite different types of reaction may be used to synthesize such bimetallocarbaboranes."" 2, 1,6-C,HsCoC2B7H9, when reduced with Na-naphthalene in THF and subsequently treated with Na'Cp- and CoCl,, gives the expected (C5H,)2Co,C2B,H9, and a new trimetallic carbaborane formulated as (C,H,)Co,C,B,H,. The latter decomposed in solution to give the former, and the reaction is believed to be as shown.in Figure 17. Thus the structures (on the and basis of n.m.r. and mass spectral data) are 1,2,8,3,6-(C,H5),Co3C,B7H9 1,~,~,~-(C,H,)COC,B,H,.'~~ When tetrakis(triethy1phosphine)nickel is added to a solution of the arachno-carbaborane l,3-B7C,H,,Me,, one molecule of H, is evolved and red crystals of Ni(B,C,H,Me,)(PEt3), (14) are deposited. A number of other n
8 Mc5
'I4
D. F. Dustin, W. J. Evans, and M. F. Hawthorne, J.C.S. Chem. Comm., 1973, 805. Evans and M. F. Hawthorne, J.C.S. Chem. Comm., 1973, 706.
"' W. J.
122 Inorganic Chemistry of the Main - group Elements Ni and Pt complexes also reacted to give products containing this ligand.Ii6 The structure of (14) was confirmed by X-ray diffraction, i.e. the geometry is that of a nido-carbaborane, but, unlike the previously reported Co(C2B7Hll)(CsH5),this compound may be regarded as a 1,2,3-q-bonded compound of Ni". These new complexes are therefore analogous to h3-allyl species, the first time that such a structure has been reported. Some new cobalt complexes of the nido- 11-atom metallocarbaborane class have been reported by Hawthorne et al.,"' e.g. X-[9-(q-CsHs)-11C,H,N-7,8, 9-C2CoB8Hlo] and X-[ 1,2- C,B,H, ,-3 ,1'-Co-7'-C,H,N-2',4'C2B8H,](15). The structure of only one enantiomer of (15) is illustrated. 10
n
A new experimentally convenient route to icosahedral bimetallocarbaboranes has been reported by Evans and Hawthorne."' Thermally induced intermolecular metal- transfer reactions of the type:
I" I17 I IX
M. Green, J . Howard, D. L. Spencer, and F. G . A . Stone, J.C.S. Chem. Cornrn.. 1974. 1S3. C. J . Jones, J . N . Francis, and M. F. Hawthorne. J. Amer. Chem. SOC.. 1073, 95, 7633. W . J . Evans and M. F. Hawthorne, .I. Amer. Chem. SOC.. 1974, 96, 301.
Elements of Group I11 123 occur, yielding 5 isomeric species, which could be separated chromatographically. One was unambiguously characterized as 2,9-(q-C,H,)-2,9-Co21,12-C2BsHlo (16).
0BH CH
The crystal structure of 2,3-(q -CsH5)2-2,3-Co21,7-C2B,H,, has been determined.119The molecule may be described as a distorted icosahedron in which the two Co atoms occupy adjacent vertices [2.387(2) A apart], being co-ordinated also to two cyclopentadienyl rings [average Co-C bond distance 2.05(2) A]. Polyhedral expansion of 1,6-C2B8HI0 gives Et,N+[(C,H,)CoC,B8H,oCoC2B8Hlo]-.An X-ray study showed the structure to be (17), with the geometrical parameters listed in Table 2.”” This represents the first crystallographic confirmation of ClV octadecahedral geometry. Na,B,,HloCH(THF)2 reacts with GeCl, to give, on subsequent treatment with Me1 or EtI, 1,2-Bl,HlOCHGeR (R= Me or Et).”’ If the Me derivative Icy 120
”’
K . P. Callahan, C. E. Strouse, A. L. Sims, and M. F. Hawthorne, Inorg. Chern., 1974, 13, 1397. G. Evrard, J . A. Ricci jun., I. Bernal, W. J . Evans, D. F. Dustin, and M. F. Hawthorne, J.C.S. Chem. Comm., 1974, 234. G. S. Wikholrn and L. J. Todd, J . Orgartometallic Chem., 1974, 71, 219.
124
Inorganic Chemistry of the Main -group Elements (' >.B 115)
is refluxed with benzene and piperidine, further addition of NMeiClprecipitates Me,NIBloHloCHGe]. The latter reacts with Cr(CO), to give Me," 1,2-B loHloCHGeCr(CO),].
Table 2 Average interatomic distances/A in Et4N'[(C,H5)CoC2B8H10CoC2B~HJ Co(l)-Co(2) Co(1)-C (terminal cage) Co( 1)-C (bridging cage) Co(1)-B (bridging cage) Co(2)-C (bridging cage) Co(2)--B (bridging cage) Co(2)-C (of C5H, ring) C-B (bridging cage) C-B (terminal cage) B-B (bridging cage) €3-B (terminal cage)
3.173 1.978 2.094 2.090 2.0 I 0 2.048 2.063 1.702 1.595 1.797 1.812
Removal of bridging protons from B,,CH, (by ethanolic KOH), with subsequent addition of C,H, and CoC1, and oxidation, gives [(q -C5H5)Co'II (?r-7-B,oCH,,)]-.'22 The neutral Nil" analogue (q-C,H,)Ni'"(q -7BloCHll)was also reported, and this undergoes thermal rearrangement to a -2- and -l-BloCHll). mixture of the isomers (q-C5H5)Ni'"(r) If the 13-vertex cobaltacarbaboranes (q-C,H,)COC~B,~H,~ are treated with ethanolic KOH and cyclopentadiene in the presence of an appropriate metal salt, new 13-vertex bimetallocarbaboranes are produced. These may contain similar or dissimilar metal atoms, and they contain one less boron atom than the original monometallocarbaborane. This replacement of a 12'
R. R. Rietz, D. F. Dustin, and M . F. Hawthorne, inorg. Chew., 1974, 13, 1580.
Elements of Group 111 125 boron atom by a metal atom has been termed a 'polyhedral subrogation' reaction. An example of such a reaction is: 2[4-(q - C ~ H ~ ) - ~ -1,8-C2B,oH12] CO+ 3CoC1, + 2C&
1
+ 6Et0-
KOH EtOH
2[4,5-(q-C,H,)z-4,5-C0,1,8-C,B,HIl] + 2B(OEt)3+ 2H2 + COO+ 6C1A similar reaction involving FeC1, produced ( 18).123
The RhI-carbaborane complex (Ph3P)2Rh(CBloHloCPh)forms orthorhombic crystals. The Rh-carbaborane interaction comprises a Rh-C a-bond and a Rh-H-B bridge (19).12' An alternative description is of
electron donation from a suitable Rh hybrid orbital into an empty orbital delocalized over the C-B-H group of the anionic (CBloHloCPh)-ligand. Treatment of (Me,SOH)' [(C,B,H,,),Co]- with S,Cl2 in CH2Cl2,followed by alkaline methanolysis, forms the anion 8,8'-S(C2B,HIo),Co-(isolated as 124
D. F. Dustin and M. F. Hawthorne, J. Amer. Chem. SOC., 1974, 96, 3462. G . Allegra, M. Calligaris, R. Furlanetto, G. Nardin, and L. Randaccio, Cryst. Struct. Comm., 1974, 3, 69.
126 Inorganic Chemistry of the Main-group Elements the Cs’ Addition of dimethyl sulphate gave the neutral complex 8,8’-MeS(C2B,H,,),Co. Two Rh hydridometallocarbaboranes have been prepared which are active catalysts for the homogeneous hydrogenation of hexenes.lZ6They are 3,3-(Ph3P),-3-H-3, 1,2-RhC2B,H,, and 2,2-(Ph3P),-2-H-2, 1,7-RhC2B,H,, . They are prepared by the reaction of Me3NH+salts of (7,8-C2B,H,,)- or (7,9-C2B,HJ with the [Rh(PPh3),]+ cation in methanol solution. These complexes also catalyse the H-D exchange reaction of D, with carbaboranes very effi~ient1y.l~’Thus, deuteriation of C,B,,H,, occurs at least one order of magnitude faster with them than with any other catalyst so far examined. An X-ray investigation of the structure of closo- 1,l-(Me2PhP),-2,4-Me21,2,4-PtC2B,H, has been carried out.lZ8The structure found is (20), with the
”’ J. 12’
’*’
PleSek, S. Hefmanek, and Z . JanouSek, Chem. and Ind., 1Y74, 108. T. E. Paxson and M. F. Hawthorne, J. Amer. Chem. SOC.,1974, 96, 4674. E. L. Hoe1 and M. F. Hawthorne, J. Amer. Chem. SOC., 1974, 96, 4674. M Green, J . L. Spencer, F. G. A . Stone, and A. J. Welch, J.C.S. Chem. Comrn., 1974, 571.
Elements of Group III
127
Pt atom situated approx. 1.75 A above the CZB3 bonding face. The species nido- 10,10-(Et3P),-2,8-Me,- 10,2,8-PtC2B,H, is prepared from closo-Me,1,6-C,B7H, and Pt(PEt,),. The Pt co-ordinates boron atoms 5, 6, 7, and 9, producing a nido- 10-atom polyhedron approximating to a bicapped square antiprism. N.m.r. data on the latter indicate that it is stereochemically non-rigid. The fluxional ‘red’ isomer of (n-C,H,)Co(B,,C,H,,) crystallizes in the The Cp ligand is symmetrically orthorhombic space group P ~ a (C:,).”’ 2 ~ bound to the Co, while the B10C2Coskeleton defines a triangulated (1,5,6,1) 13-apex docosahedron, the equatorial C-B-C-B-B-B belt being bonded to cobalt. Some peculiarities in this structure are illustrated in Figures 18 and 19. Thus the hexagonal bonding face of the carbaborane ligand is non-planar, and within this ligand there are some unusual bonding arrangements. This is most marked within the four-membered units B(2)B(3)-B(8)-C(7) and B(2)-B(6)-B(12)-C(7); the B(12)-C(7) and B(8)-C(7) bonds are very short [1.527(6), 1.429(10)A] and C(7) is only five-co-ordinate. B(2), however, is linked to 7 other atoms, the bonds B(2)-B(8) and B(2)-B(12) being very long. Polyhedral expansion reactions have been extended to produce the first 14-vertex metallocarbaboranes.130 Thus, X-[4,1,1 2-CsH,CoCzB10H12]gives
Figure 18 A view of the (T~-C,H,)CO(~,~-B,,C~H,,) molecule showing the two anomalous four-membered systems : B(2)-B(3)-B(8)-C(7) and B (2)-B(6)-B( 12)-C( 7) (Reproduced by permission from Inorg. Chem., 1974,13, 1411) 129
13”
M. R. Churchill and B. G. DeBoer, Inorg. Chem., 1974, 13, 1411. W. J . Evans and M. F. Hawthorne, J.C.S. Chem. Comm., 1974, 38.
128
Inorganic Chemistry of the Main -group Elements BI
88
&,c o
CP5
CP3 CP4
Figure 19 A view of the (T-C,H,)CO(~,~-B,~C~H,,) molecule, showing nonplanarity in the hexagonal bonding face of the carbaborane ligand. (Reproduced by permission from Inorg. Chem., 1974,13, 141 1) X - [1,14,2,10-(CSH5)2Co,C,B,oH,,](see Figure 20). A similar reaction, starting with the 4,1,8-isomer, yields an isomeric product, (1,14,2,9).
Figure 20 The formation and proposed structure of (C,H,),Co2C,B,,H,, (Reproduced from J.C.S. Chem. Comm., 1974, 38) Cobalt(I1) complexes of dpc (21) include Co(dpc)(NCS),, [Co(dpc),Br]', and [Co(dpc),I]', which have been prepared and ~haracterized.'~' They are
(21)
'"
W. E. Hill. W. Levason, and C . A. McAuliffe, Inorg. Chem., 1Y74, 13, 244.
Elements of Group III
129
reasonably stable in the absence of hydroxylic solvents. The only Ni" complex prepared was [Ni(dpc),I]', which gave an electronic spectrum consistent with trigonal-bipyramidal co-ordination at the nickel atom. The reaction of 2-R-1,2- and 7-R-1,7-B,,C,Hll (as the 1-Li derivatives), where R = Me or Ph, with (Ph,P)RhCl gives rise to an unusual series of three-co-ordinate complexes containing a metal-carbon a-bond: (Ph,P)Rh(~-carb).'~~ These readily react with 0, to give an oxygen complex [with 40,) at 900cm-'] and (reversibly) with CO to form (PPh,) Rh(CO),( u - carb) . The reaction of 1-lithiocarbaborane derivatives with cis-(PR:),PtCl, or trans -(PR:),PtCl, yields cis-(PR:)PtCl(a-carb) and cis(PR:),Pt(PR:CH,CHR')(u-carb), respectively (R'= Et, Pr", or Ph; R2= H or Me)."' Compounds containing B-C Bonds.-An a b initio MO calculation has been carried out on H3B,C0.13, The adduct H3B,C0,NMe3is only stable at low temperatures, decomposing to CO and H,B,NMe3 on ~ a r m i n g . ' ~1.r. ' assignments and some "B n.m.r. data have been reported for the adduct, the assignment of v(C0) to a band at 1798 cm-' being consistent with the postulated O + N co-ordination. B,H,CO may be prepared in a convenient one-step synthesis from B2H6 and CO in a hot-cold r e a ~ t 0 r . lThe ~ ~ carbonyl derivative may then react with C2H4 to give (CH,),B,H,. The structure of this is (22), as shown by 'H
\ H-B-H
/
n.m.r. spectroscopy. The i.r. spectra of this and its C-methyl and CC'dimethyl derivatives are also consistent with this structure. Thermal decomposition of triborane(7) carbonyl, B,H,CO, gives the new species bis(carbonyl)diborane(4), B,H,(CO),. This is relatively stable, and preliminary X-ray data suggest that it possesses a 1,2-disubstituted, ethanelike with B-B 1.78(1), B-C 1.52(1), C-0 1.125(7), B-H(1). 1.14(6), and B-H(2) 1.11(6)A. 13*
133 134
136
13'
S. Bresadola and B. Longato, lnorg. Chem., 1974, 13, 539. S. Bresadola, A. Frigo, B. Longato, and G. Rigatti, Inorg. Chem., 1973, 12, 2788. S. Kato, H. Fujimoto, S. Yamabe, and K. Fukui, J. Arner. Chem. SOC., 1974, 96, 2024. J. C . Carter, A. L. Moye, and G. W. Luther, J. Arner. Chem. SOC., 1974, 96, 3071. T. Onak, K. Gross, J. Tse, and J. Howard, J.C.S. Dalton, 1973, 2633. J . Rathke and R. Schaeffer, Inorg. Chem., 1974, 13, 760.
130
Inorganic Chemistry of the Main-group Elements ~-Bis(cyanotrihydroborato)-tetrakis(triphenylphosphine)dicopper(I)crystallizes in the space group P2Jn.13* The H,BCN- ligands bridge the' two copper atoms, forming a ten-membered non-planar ring, with Cue * -Cu= 5.637(2) A. The structure is a rare example of a hydroborate ligand bonded by only one of its H atoms to a metal atom, and the geometry of the BH,CN ligand is close to that of CH,CN in related complexes. Bis(cyanotrihydroborato)- 1,1,4,7,7-pentamethyldiethyIenetriaminecopper(I1) crystallizes in the space group Pbca. The Cu is five-co-ordinate, forming a distorted square-based pyramid, and'the two NCBH; ligands are distinct, one apical [r(Cu-N) = 2.153(3) A] and one in the 'square plane' [r(Cu-N) = 1.980(4) hi]."' Ab initio MO calculations on vinylborane, H,C=CHBH,, yield a value for the barrier to rotation about the B-C bond of 7.6 kcal ~ O I - ~ . The ~"" optimum values for the C=C and B-C bond lengths were 1.327 and 1S S 4 A (planar form) or 1.32 1 and 1.574 A (for the perpendicular conformation). The i.r. and Raman spectra of trivinylborane, B(CH=CH,),, may be assigned on the basis of the planar, C,,, structure determined by electron diffraction. The values of v(B-C) and v(C=C) are consistent with some B-C ~r-interaction.~"~ A second, independent, investigation of this vibrational spectrum agrees with these conclusions for the solid phase, but in the fluid phases an additional conformer, of C, symmetry, was detected. 14' This form may be obtained by twisting the vinyl groups out of the molecular olane. Microwave, i.r., and Raman spectra were also obtained for vinyldifluor~borane.'"~ The barrier to rotation about the two-fold barrier was calculated to be 4.17 kcal molF'; this is quite large, but it is not large enough for B-C multiple bonding to be postulated. Vapour-phase i.r. and Raman spectra of HC=CBX, ( X = F or Cl) have been obtained for several isotopic species.'"" Almost complete vibrational assignments were made for both molecules. Some assignments have also been proposed from the i.r. and Raman spectra of X,BCH=CHBX, and X,BCH,CH,BX, (X = F or Cl).l"' The allyl-borane (23) is much more stable than other allylborane systems, most of which undergo spontaneous rearrangements. 146
13'
'" 14') 141
'" '43 '44
14'
K. M. Melmed, T.-I. Li, J. J . Mayerle, and S. J. Lippard. J. Amer. C'hem. SOC..1974, 96,6Y. B. G. Segal and S. J. Lippard. Inorg. Chern., 1974, 13, 822. H. M. Seip and H. H. Jensen. Chem. Phys. Letters. 1974. 25, 209. A. K. Holliday, W. Reade, K . R. Seddon, and I. A. Steer, .1. Organometallic Cham., 1974, 67, I. J . D. Odom, L. W. Hall, S. Riethmiller, and J . R. Durig, Inorg. Chem., 1974, 13, 170. J . R. Durig, R. 0. Carter, and J . D. Odom, I n o r g . Chem., 1974. 13, 701. J . M. Burke, J . J . Ritter, and W. J . Lafferty, Spectrochirn. Acta, 1974, 30A, 993. W. Haubold and J. Weidlein. Z . anorg. Chem., 1974, 406, 171. K. G. Hancock and J. D. Kramer, J. Amer. Chern. SOC.,1973, 95, 6463.
Elements of Group 111
131
Et 'BNMe,
Fe I
(23)
(24)
/ MeCH \CH=CH,
BI, reacts with ferrocene at -10 "C in benzene to give (24).14'This reacts further to form the 1,l'-di-B1,-derivative. Heating 1,2-bis(dichlorylboro)ethane gives a low yield of the boraadamantane (BCl),(CH),.'"" The C1 atoms may be substituted by Br (using BBr3) or Me (using SnMe,). Mass and vibrational spectra have been presented for the chloro-species. A rhombohedra1 boron carbide B& results from the pyrolysis of BBr,Ch-H, mixtures on Ta or BN substrates at 900--1800°C. It has the crystal-chemical composition B,,(CBC), i.e. B,, icosahedra and linear CBC Excess carbon up to a resultant formula of B,,C, can be accommodated in the structure. A number of new tetragonal and orthorhombic B/C phases have been B,,B,(BC)] and ~haracterized.'~'The tetragonal species were B51C [i.e. under B25C (i.e. B,,B,C,), which result from pyrolysis of BBr,-C%-H, normal pressure. The decomposition of B13+CI, at 1050 "C and lo-' Torr produces B,,C, [i.e. B,,(BC)C,].A11 contain four B,, icosahedra and four single atoms (3B + lC, 2B + 2C, and 1B+ 3C, respectively). The icosahedra are linked by direct B-B bonds and by bridging with the single atoms. The B3&48), which latter reaction also gives the orthorhombic B8C (i.e. contains several B& units linked by numerous additional carbon atoms in the ab plane.
-
-
-
-
Aminoboranes and Other Compounds containing B-N Bonds.Structural parameters for the planar and orthogonal forms of H,BNH, have been computed from ab initio calculations.1s1The best estimate of the internal rotation barrier is 33.3 kcal mol-'. Using the geometry recently deduced for H2NBF, by microwave spectroscopy, MO calculations (CNDO and INDO) have been carried out on this The following conclusions were reached: (a) The 120" FBF and HNH angles are due to repulsive N- .F and B- .H interactions. ( b ) The
-
'47
14'
14Y 150
15'
-
W. Ruf, M. Fueller, and W. Siebert, J. OrganometaIlic Chem., 1974, 64, C45. M. S. Reason, A. G. Briggs, J. D. Lee, and A. G. Massey, J. Orgaltometallic Chem., 1974, 77,
C9. K. Ploog, J. Less-Common Metals, 1974, 35, 131. K. Ploog, J. Less-Common Metals, 1974, 35, 115. 0. Gropen and H. M. Seip, Chem. Phys. Letters, 1974, 25, 206. C. Leibovici, J.-F. Labarre, and F. Gallais, Compt. rend., 1974, 278, C , 327.
132 Inorganic Chemistry of the Main - group Elements B-N bond order is approx. 1.3. ( c ) There is very little transfer of charge F,B + NH2, only ca. 0.015 electron. Tetrachloroaminoborane, Cl,BNCl,, has been characterized as an intermediate in the reaction: 3BC1, + 3NC1, + (ClBNCl), + 6C1, The following vibrational assignments, in particular, were given for this species: B-N stretch (A,) 1350 ("B), 1312("B); B-C1 stretch (B,) 1026 ('OB), 986 ("B); B-Cl stretch (A,) 446; N-Cl stretch ( B , ) 735; and N-C1 stretch (A,) 541 cm-'. The tetrachloroaminoborane is extremely and unpredictably explosive, so great care must be exercised.lS3 An ab initio M O calculation carried out on H3B,NH3(borazane) gave an insight into the origin of charge transfer and bond formation between BH, and NH,.15" The calculation involved an expansion of the MO's of the addition compound in terms of those of the separate NH, and BH,. Ab initio LCAO-MO-SCF calculations on the same species have given values for the electric field gradients, electric fields, diamagnetic shieldings, dipole moment, second moment, and diamagnetic su~ceptibility.'~~ A C N D 0 / 2 calculation performed on Me,N,BH, indicates that the preferred conformation is staggered, and that the energy barrier to the process: staggered S eclipsed is 2.91 kcal mol-' (experimental value 3.4, theoretical value for Me,P,BH, is 4.09 kcal m ~ l - ' ) . l ~ ~ Stepwise formation of B -halogenated amine-boranes occurs by the reaction of halogens or H X with the parent amine-borane. The progress of the reaction may be followed by monitoring the 'H n.m.r. spectrum of the reaction The end product of the bromination reaction on Me3N,BH3 is Me3N,BBr,, while for Me,CNH,,BH, chlorination yields Me,CNH2,BCl, and fluorination [Me,CNH,]'BF;. A detailed assignment and normal-co-ordinate analysis has been reported for the vibrational spectra of Me,N,BH,, Me3N,BD3, (CD,),N,BH,, and (CD,),N,BD,.15* The B-N and C-N stretching modes are extensively mixed, although the bands at 680, 660, 641, and 610 cm-' (for the 4 isotopic species) possessed more than 65% of B-N stretching character. The B-N stretching force constant was calculated as 2.59 mdyn A-1. Evidence has been presented for the mechanism of the halogen-exchange processes in the systems Me,BX,+BY,, where X and Y are ha10gens.l~~ ls3
156 157
t TX
J . G . Haasnoot and W. L. Groencvcld, Z . Naturforsch., 1974, 29b, 52. H . Fujimoto, S . Kato, S . Yamabe, and K . Fukui, J . Chem. Phys.. 1974, 60,572.
M . Dixon and W. E. Palke, J. Chem. Phys., 1974, 61, 2250. F. Crasnier, J. Chim. phys., 1973, 70, 1731. .I. M. Vanpaaschen. M. CJ. Hu, L. A. Peacock, and R. A. Geanangcl, Synth. React. lnorg. Metal-org. Chew., 1974, 4, 11. J . D. O d o m . J. A. Barnes, B. A. Hudgens, and J . R. Durig, J . Phys. Chem., 1974, 78, 1503. B. W . Benton and J . M. Miller, Canad. J. Chem., 1974, 52, 2866.
Elements of Group III
133
Isotopic labelling shows that no B-N bond rupture occurs, and that X or Y could be the heavier halogen. Except for Me3N,B13a bridged intermediate (five-co-ordinate at B) may be postulated. In the Me,N,BI, case ionic predissociation (B-I bond breaking) is indicated. Gas-phase halogenexchange reactions always occur via B-N bond cleavage. The role of co-ordinated BH, and BH, groups as proton acceptors in hydrogen-bonding has been studied, using the complexes between phenol and Me,N,BH2X (X = H, C1, Br, or I), py,BH3, and Et3P,BH3.16'Enthalpies of formation were deduced from measurements of the absorbance of the free O H stretching band over a range of temperature. Values of - A H fell within the range 1.7-3.5 kcal mol-l, while in the Me3N,BH2X series the strengths of the hydrogen bonds fell in the order: H > Cl> Br> I. The monochloroborane complex with triethylamine (ClBH,,L) reacts at 120 "C with heptamethyldisilazane, eliminating Me,SiCl, but the expected product, H,BNMeBH,, is unstable, and only decomposition products (-BH-NMe-), can be isolated. With the corresponding ether complex at 60 "C, reaction gives the silyl system H,BNMeSiMe, when the molar ratio is 1:1, but with a larger amount of the chloroborane adduct the product is a diboranyl compound Me,SiNMeBzH,.'6' X-Ray diffraction studies on 2,6-lutidine-chloroborane, C,H,N,BH,Cl, give the following bond lengths and angles: B-Cl 1.901(3), B-N 1.590(4), B-H 1.07(3), 1.17(3) A, LNBCl 107.3(2)", LBNC 121.0:, 120.2(2)0.162 Near- and far-u.v. spectra have been recorded for the aminoboranes (Me,N),BX,-,, where n = 1, 2, or 3; X = H, Me, F, C1, or Br.16' For the mono-aminoboranes the 7~ -+ n* transitions dominate the spectra, but for the di- and tri-aminoboranes there are also Rydberg series and some single Rydberg transitions, partly preceding the 7~ + T * band. Transamination of (dimethy1amino)diphenylborane with 2-, 3-, or 4aminopyridine gives the corresponding (pyridinylamino)diphenylboranes, while the B -triphenyl-N-tris(4-pyridyl)borazineis obtained by transamination of bis(dimethy1amino)phenylborane with 4-amin~pyridine.'~" Resonance line broadening due to chemical exchange and quadrupoleinduced relaxation in the 'H and "B n.m.r. spectra of some boron-nitrogen adducts ArNMe,,BY, (Y= halogen) has been observed and used to determine the mechanism of amine scrambling in these adducts.16' This is thought to occur via a unimolecular ionization rather than a B-N bondrupture process.
'"
M. P. Brown and P. J. Walker, Spectrochim. Acta, 1974, 30A, 1125. A. F. Zhigach, E. S. Sobolev, R. A. Svitsyn, and V. S. Nikitin, J . Gen. Chem. (U.S.S.R.), 1973, 43, 1949. I 6 2 W. R. Clayton, A. V. Fratini, R. Remmel, and S. G . Shore, Cryst. Struct. Comm., 1974, 3, 151. 163 W. Fuss, Z . Naturforsch., 1974, 29b, 514. L64 W. L. Cook and K. Niedenzu, Synth. React. Inorg. Metal-org, Chem., 1974, 4, 53. 16' J. R. Blackborow, J.C.S. Dalton, 1973, 2139.
Inorganic Chemistry of the Main-group Elements 134 The crystal and molecular structures of ammonia-isothiocyanoborane, H,N,BH2NCS, have been determined;166these show that the B-N(of NH,) NCS) bond length is bond length is 1.578(8)A while the B-N(of 1.534(8) A. A study of the exchange reactions of adducts of NN-dimethyl-o -tohidine with BCl, and PhBCl,, o-MeC6H,NMe2,BC1,, and o-MeC6H,NMez,PhBC1,, and of NN-dimethylaniline with PhBCl, and PhNMez,PhBClz, has shown that, as for the adducts p-ClC6H,NMe2,BC1, and PhNMe2,BC1,, the ratedetermining step in amine exchange is usually a unimolecular ionization of the a d d ~ c tThe . ~ ~first ~ three adducts, however, show equilibrium ionization that is an order of magnitude greater than that of the last two. Cyanoborane adducts of morpholine and dimethylamine undergo the following hydrolysis reaction: R,NH,BH,CN
+ 2 H z 0+ 2 0 H - -+ R,NH + B(OH), + 2H,+ CN-
Kinetic studies suggest that the mechanism involves removal of the Nbonded proton by OH- in a rapid pre-equilibrium, followed by the ratedetermining, dissociative decomposition of the resultant conjugate base.168 The course of the reaction between halogenoboranes and the aminobenzonitriles depends upon the position of the NH, group.169With the 3- and 4-amino-derivatives the products are the corresponding amine-boranes and compounds obtained by loss of hydrogen halide, (25) and (26). With the 2amino-benzonitrile, however, the nitrile group is inserted into a B-halogen
bond (27), and derivatives of the 1,3,2-diazaboranaphthalene ring ( 2 8 ) result by elimination of HX.
Ihh lh7 IhX
lhY
S. S. Kendall and W. N . Lipscomb. Inorg. Chem., 1973, 12, 2920 J . R Blackborow, M. N. S. Hill, and S. Kumar, J.C.S. Dalton, 1974, 311. C. Weidig, S . S. Uppal, and H . C . Kelly, Inorg. Chern., 1974, 13, 1763. A Meller. W. Maringgele, and G. Marech, Monatsh.. 1974, 105, 637.
Elements of Group I11
135
The thermal decomposition of hydrazine-borane is a rather complex process, but the first stage appears to be a loss of molecular hydrogen. The major, final product may be formulated as (H2BNHNHBH2),.'70 14Nand "B chemical shifts have been reported for 19 silylaminoboranes, e.g. R:B-BR2-SiMe, (R' = Me, R2= H, Me, Et, P i , Bus, or But; R' = Et, R2= H or Me; R' = Ph, R2= H or Me), (29), and B[NMeSiMe,],."' (pp)-nSiMe,
I
MeB
I SiMe, (29)
Bonding between B and N, as well as geometric effects, were used in analysing the data. The Si-N bonds of B(NMeSiMe,), are successively cleaved by Me2BBr As n to give all the members of the series (Me2BMeN),B(NMeSiMe,)3-,.'72 increases these products become increasingly susceptible to thermal decomposition. 'H and "B n.m.r. spectra were obtained and discussed. Tris(organoamino)boranesmay be rapidly and conveniently prepared by the interaction of BF,,Et,O and N-lithio-dialkyl-, -diaryl-, and -alkylarylamines in THF: R'R'NH
+ n-C,H,Li
3R1R2NLi+ BF,,OEt,
hzfeR'R2NLi+ n-C4Hl, THF,:ebanc.> (R'R'N),B + 3Et,O + 3LiF
The procedure is more general and less sensitive to steric effects than previous ones, and it gives well-known, as well as new, tris(organoamino) boranes in high yields.", BCl, forms 1: 1 adducts with methacrylonitrile, CH2=C(Me)CN, and Nbenzylidenemethylamine, PhCH=NMe, but organoboranes, e.g. BEt, or B(C3H,),, add across the C = N bond to give CH,=C(Me)-C(R)=N-BR, and PhCHR-NMe-BR,, respe~tive1y.l~~ Variable-temperature "F n.m.r. spectra of mixtures of an amine (A) and B(OR)F, between -40 and +60"C reveal that at low temperatures ( < -30 "C) the adduct A + B(OR)F, is stable. Above this temperature rearrangement occurs, yielding B(OR), and A + BF,.175 17"
17'
17'
'73 174
175
A. F. Zhigach, V. V. Zakharov, G. B. Manelis, G. N. Nechiporenko, V. S. Nikitin, and B. M. Esel'son, Russ. J. Inorg. Chem., 1973, 18, 931. H. Noth, W. Tinhof, and B. Wrackmeyer, Chem. Ber., 1974, 107, 518. H. Noth and W. Storch, Chem. Ber., 1974, 107, 1028. W. R. Purdum and E. M. Kaiser, J. Inorg. Nuclear Chem., 1974, 36, 1465. A. Meller and W. Gerger, Monatsh., 1974, 105, 684. J. P. Tuchagues and J. P. Laurent, J. Inorg. Nuclear Chem., 1974, 36, 1469.
136 Inorganic Chemistry of the Main - group Elements Contrary to reports in the literature, the reaction of (dialky1amino)diboranes with tertiary amines proceeds via an intermediate complex in which the diboranyl group is preserved. The final products are mixtures of aminoboranes and amine-boranes. 176 Reactions with sym - and asym dimethylhydrazines are also reported, giving products such as H,B-NMeNMe-BH2 and Me,NNH-BH,, respectively. A number of photochemical reactions of tetrakis(dimethylamin0)diborane, B2(NMe2)+have been i n ~ e s t i g a t e d . The ' ~ ~ products of the reaction in CCl, solution at 2 5 4 0 ° C using 300nm radiation are (Me,N),BB(NMe2Cl), B(NMe2),, and (Me,N),CH,. Cationic boron(m) chelates, formulated as (30), can be prepared by transamination reactions between B(NEt,), and biguanides, followed by treatment with HCl.'78Similar guanylurea derivatives can also be obtained.
t
c1-
Compounds with the molecular formula (C,H,N,),BX, where X = F or C1, have been previously isolated from reactions of halogenoboranes and phthalodinitrile. The structure of the chlorine compound has now been determined and shows a phthalocyanine-like structure (3 l)."' The system is bowl-shaped, in contrast to the planar phthalocyanine structure. The boron atom is co-ordinated to three N atoms (at 1.467 A, i.e. short) and one C1 (1.863 A). The .rr-electrons in the 14-membered ring form a quasi-aromatic conjugated .rr-system. Compounds containing B-P Bonds.-CND0/2 calculations on Me3P,BH, lead to a minimum energy in the staggered conformation, with rotational barriers about the P-B and P-C bonds of 4.09, 3.83 kcal mol-', respectively.180 A similar calculation for H,B-P(NH,), suggests that there is little .rr-bonding in the P-B bond.lS1 17h
177
17'
''' I80
181
A . F. Zhigach, R. A . Svitsyn, and E. S. Sobolev, .I. Gen. Chrm. ( U . S . S . R . ) , 1973, 43, 1031. K. G. Hancock, A . K . Uriarte, and D . A. Dickinson, J . Amer. Chem. SOC.. 1973,95,6980. A . Maitra and D. Sen, Indian J . Chem., 1974, 12, 183. H. Kietaibl, Monutsh., 1973. 105, 40s. M.-C. Bach-Chevaldonnet, F. Crasnier, J.-F. Labarre, and C . Leibovici, J . Mol. Structure, 1974, 20, 131. R. Dorschner. F. Choplin, and G. Kaufmann, J . Mol. Structure, 1974. 22, 321.
Elements of Group 111
137
Detailed studies have been made on the vibrational spectra of F,P-BH, was calculated for the and F3P-BD3.'" A force constant of 2.46 mdyn k1 P-B bond stretching, while assignments of 224 cm-' and 167 cm-' were made for the torsional modes of the H and D compounds, respectively. These are consistent with barriers to rotation of 4.15(H), 4.31(D) kcal mol-'. 1.r. and Raman spectra of H,P,BX, and D,P,BX, (X = C1, Br, or I) have been reported and assigned. A normal-co-ordinate analysis, (modified Urey-Bradley force field) confirmed the assignments. All the adducts gave a best frequency fit for an assumed value for the HPH bond angle of ca. 105-1 06". The systems PC1,-BF,, PC1,-BCl,, MePC1,-BF,, MePC1,-BCl,, Me,PClNo evidence was BF,, Me,PCl-BCl,, and Me,P-BCl, have been found for PC1,-BF, or -BCl, adducts, nor for MePC1,-BF,, although MePCl,-BCl, is formed. Other previously reported species were confirmed. The basicities for the P-compounds appear to be in the sequence Me,P> MezPCl>MePCl, ( >> PCl,). The reaction of PMe,C1+B,H6 yields the new adduct ClMe2P-BH,.'85 A complete vibrational assignment has been proposed for this, and some 'H and "B n.m.r. data have also been reported. 1.r. and n.m.r. parameters (especially '.IpB)have been reported for the newly characterized series of adducts R3-,XnP -+ BH,, where R = But, 0 < n < 3 , and X = F or C1.'86 A further, extensive, investigation of the n.m.r. spectra of phosphineborane adducts has been made by Rapp and Drake."' The following data were obtained: (a) 'H and "B n.m.r. parameters for R,PH3-,,BX, (R = Me or Ph; n = 0, 1, or 2; X = H, F, C1, Br, or I): (b) 'H, "B, and ,'P parameters for the BX,H3-, (n = 0, 1, or 2; X = C1, Br, or I) adducts of all R,PH,-,; and ( c ) I9F parameters for all of the compounds R,PH3-,,BF3 except PH3,BF3. BCl,, BBr,, and BI, form 1: 1 adducts with MePCl,. BF, does not react, and B2H6 gives a mixture of products.188Halogen exchange is found to occur in all the MePC1, adducts with BBr, and BI,. Adducts of BI, and BBr, with various tertiary phosphines and their chalcogenide derivatives, together with 'H and "B n.m.r. spectra of many of these, have been reported.189 Although the 'H(CH,)-3'P coupling constants are nearly identical in the series Me3P,BX, (X = F, C1, Br, or I), J,, for the 182
'*' 185
J. D. Odom,S. Riethmiller, S. J. Meischen, and J. R. Durig,J. Mol. Structure, 1974,20,471. J. E. Drake, J . L. Hencher, and B. Rapp, J.C.S. Dalton, 1974, 595. R. T. Markham, E. A. Dietz jun., and D. R. Martin, J. Inorg. Nuclear Chem., 1974, 36, 503. J . D. Odom, S. Riethmiller, and J . R. Dung, J. Inorg. Nuclear Chem., 1974, 36, 1713. C. Jouany, G. Jugie, J.-P. Laurent, R. Schmutzler, and D . Stelzer, J. Chim. phys., 1974, 71, 395. B. Rapp and J. E. Drake, Inorg. Chem., 1973, 12, 2868. R . M. Kren, M. A. Mathur, and H. H. Sisler, Inorg. Chem., 1974, 13, 174. M. L. Denniston and D. R. Martin, J. Inorg. Nuclear Chem., 1974, 36, 1461.
138
Inorganic Chemistry of'the Main-group Elements Me,P,BI, species is much lower than the values for other members of the series. The nature of donor-acceptor interactions in aminophosphine-borane adducts may be elucidated by studying the chemical behaviour of the BH, The P atom is a better acceptor group and 'H, IIB, and 31Pn.m.r. than N towards B when the P and N are directly linked (as in Me,NPMe,), although the N co-ordinates preferentially to B when the P and N are separated by a methylene bridge [e.g. in (Et,NCH,),P]. Treatment of H2P(BH3),Na with an ethereal solution of HCl at -96°C leads to the formation of an associated p -phosphinodiborane, (F-H,PB,H,),. 1.r. and n.m.r. ("B) spectroscopy point to the formation of B-HB bridges. Thermal decomposition leads to elimination of B,H, and formation of polymeric phosphinoborane, and this is analogous to the behaviour of p-HzN-BzH5.191 Similar compounds in which the P atom is substituted by an organic group can be prepared by reactions of MePH(BH,),Li, Me2P(B H,) ,Li, or PhPH(BH,) ,Li. N.m.r. and i.r. data have been listed for the adduct PF2(CH=CH2),BH,.'92 v(PB) is at 584 cm-'. Compounds containing B-0 Bonds.-Mehrotra et al. have written a review on compounds containing M-0-B linkages, i.e. metalloboroxane~.'~~ Boron reacts with oxygen at atmospheric pressure and temperatures of 1250--1400°C (in the presence of traces of Pt) to give the suboxide B,O, which was characterized by X-ray powder d i f f r a ~ t i 0 n . l ~ ~ A study has been made of the temperature dependence of the isothermal compressibility of B,0,.195 Corsaro and Jarzynski have reported on the thermodynamic properties of B,O, in the glass ~ e g i 0 n . l ~ ~ No binary solid phases are observed in the B,03-MOO, 1.r. spectra of BO; in potassium and rubidium halide lattices have been observed, and the data so obtained used to determine the anharmonic force-field of BO;.198 Assignments of some vibrational modes of BO:- in an indium borate crystal have been attempted, together with some for lattice modes.199 A theoretical analysis has been made of the miscibility gaps in the alkali-metal borates, based on the concept of regular solutions. In each system the structural units which control the entropy of mixing are thought 1 YO
c'. Jouany, J.-P. Laurent. and G. Jugie, J.C.S. Dalton, 1974, 1SlU. H. Hofstiitter a n d E. Meyer, Monatsh., 1974, 105, 712. I y 2 E. L. Lines and L. F. Centofanti, Inorg. Chem., 1974, 13, 1517. S . K . Mehrotra, G . Srivastava, and R. C. Mehrotra, J. Organometallic Chem., 1974, 73, 277. Iq4 H . Jean-Blain a n d J. Cueilleron, Compt. rend., 1973, 277, C, 977. 195 J. A. Bucaro and H. D. Dardy, J. Chem. Phys., !974, 60, 2559. I Yh R . D. Corsaro and J. Jarzynski, J. Chem. Phys., 1974, 60, 5128. Iy7 V. T. Mal'tsev, P. M. Chobanyan, and V. L. Volkov, Russ. .I. Inorg. Chern., 1973, 18, 1068. I Y x D. F. Smith jun., Spectrochirn. Acta, 1974, 30A, 87s. l Y y R. Frech, J . Chem. Phys., 1974, 60, 1678. IY'
Elements of Group I11
139 to be the stoicheiometric compounds at the limit of the alkali-rich edge of the gap, and a complex boron trioxide structure.’00 The depression of the transition temperature of Glauber’s salt has been measured in borate solutions to gain information on the nature and concentration of the species present.’’* The data support the previous observation that in the boron concentration range 0.1-0.2 mol 1-’ only monomers and tetramers are present. Bismuth orthoborate, BiBO,, is obtained by melting a mixture of H,BO, and Bi,O, in stoicheiometric proportions, and Two polymorphs (distinguished by their i.r. and Raman spectra) are produced depending upon the cooling conditions. At 600°C BiB03 rapidly decomposes to a mixture of 2Bi203,B203and 3Biz03,5B203. The isomeric 12-tungstoborates have been shown to be respectively quadratic and hexagona1.*03Conditions for their isolation in pure form, without recourse to tedious fractional recrystallization, were established. Heats of reaction of pentasubstituted Li+,Na+,and K’ tungstoborates with NaOH have been determined.’04 The salts do not contain hydrogen ions which could react with OH- as readily as the ions in tungstoboric acid. Tungstoboric ($B203,12W0,,nH2), tungstovanadoboric (iB203,10W03,V,O,,nH,O), and molybdotungstoboric ($B,0,,6MoO3,6WO,,nH2O) acids give rise to two titration jumps in potentiometric titrations. These correspond to 3 and 5 dissociable protons (in amphoteric solvents such as methyl ethyl ketone).’” In a protic solvent (acetic acid) the acids are only tribasic, since here the boric acid is the complex-forming species. A study of the H3B0,-CaC1,--H,O-i-C,Hl,OH system reveals that the extraction of boric acid depends chiefly upon [CaC12].’06 Complexes of borate with certain sugars give rise to broadened 13Cn.m.r. spectra, due to the presence of more than one conformer, and to the presence of two types of complex:
I -C-O,’k
‘OH
,o-c-
I
-c-0’
Replacement of borate by the diphenylborinate ion gives sharp signals, since no 13C-11B coupling seems to occur.207
201
’”’ ’(’’ 204
*”’ ’06
’07
P. B. Macedo and J. H. Simmons, J. Res. Nat. Bur. Stand. Sect. A, 1974, 78, 53. M . V. S. Jain and C. M. Jain, Indian J. Chem., 1973, 11, 1281. M. J. Pottier, Bull. Soc. chim. belges, 1974, 83, 235. G. Hem6 and A . TCze, Compt. rend., 1974, 278, C, 1417. V. I. Spitsyn, M. M. Sadykova, and G . V. Kosmodem’yanskii, Russ. J. Inorg. Chem., 1973, 18, 998. I. K. Latichevskii and N. A . Polotebnova, Russ. J. Inorg. Chem., 1973, 18, 1756. E. E. Vinogradov and L. A . Azariva, Russ. J. Inorg. Chem., 1973, 18, 859. P. A . J. Gorin and M. Mazurek, Canad. J. Chem., 1973, 51, 3277.
140 Inorganic Chemistry of the Main-group Elements Phenylboronic acid forms a 1:l complex with lactic acid in which the ligand hydroxyl proton is replaced by B.'" The stability constant of the species is (3.7 kO.4) x lo-,. The fully protonated lactic acid reacts with a rate constant of 140 1 mol-1 s-l (f10"/0), while the acid anion gives a rate constant of 1500 1 mol-' s-l (*look). Tris(trialky1tin)borates B(OSnR,), (R = Me, Et, Pr, Bun, Bu', or Ph) are produced by the reaction of boric acid with R,SnOH or (R,Sn),0.209They react with B,O, to form the trialkyltin metaborates (R,SnOBO),. The NN-diethylhydroxylamine derivatives of B and A1 are readily obtained from reactions in which the hydroxylamine is refluxed with an alkoxy-derivative of the Group I11 element:210 M(OR),+ nEt,NOH + M(OR),-,(ONEt,),
+ nROH
(M = B, R = Pr' or Bun, n = 2 or 3; M = Al, R = Pr', n = 1-3). C N D 0 / 2 calculations on the adduct Me2S0,BF, suggest that a rocking motion of the OBF, group about the S-0 bond occurs, together with a rolling of the BF, about the 0-B bond.'ll The conformational equilibrium of this complex was therefore said to be associated with a 'rock and roll' internal motion. 'H, "B, 19F, and 31P n.m.r. spectra of the systems R:MO,BF,-R:M'O (where M,M' = N, P, or As; R',R' = various alkyls) show that the donors are displaced from the complexes in the sequence R,NO b R,AsO > R,PO. These differences in the donor power of the oxygen atom can only be related to changes in the M-0 bond which are associated with the nature of M.," Methyl acetate and its sulphur analogues, MeC(=X)Y Me (where X, Y = 0 or S), all form adducts with BX, via the C=O or C=S group.213 Enthalpies of formation have been measured for BF, adducts of a number of carbonyl compounds PhCOX. The electron-donating strength of the oxygen atom is directly related to the inductive effect of the group X, although the establishment of a basicity scale for the carbonyl function must also take into account steric effects.214The following order was found for the basicities: benzaldehyde = acetophenone > hindered ketones > benzoic esters == a -chloroacetophenone > benzyl chloride. 1.r. and mass spectral data show that an intermediate in the production of 25dimethyl- 1,3,4-trioxadiborolan by the reaction of Me,BH,BH, + 0, is Me,B OOH (dimet hylboryl hydroperoxide).'l Two members of a new class of boron peroxides, (PrnO),BOOB(OPrn), 209 '''I
'11 ?I2
'I3 214 215
S . Friedman. R. Pace, and R. Pizer, J . Amer. Chern. Soc., 1974, 96, 5381. S. K. Mehrotra, G. Srivastava. a n d R . C. Mehrotra, J . Orgunornetallic Chem., 1974, 65, 361. C . K . Sharma. V. D. Gupta, and R. C. Mehrotra, Indian J. Chem., 1974, 12, 218. G. Robinet, J.-F. Labarre, and C. Leibovici, Chem. Phys. Letters, 1973, 22, 356. K. Bravo, M. Durand, J.-P. Laurent. and F. Gallais. Cornpt. rend.. 1974. 278, C, 1481). M. J . Bula, J.,S. Hartman, and C . V. Raman, J.C.S. Dalton, 1974, 725. J.-F. Gal, L. Elegant, arid M. Azzaro, Bull. Soc. chim. France, 1974. 41 1. L. Barton a n d J . M. Crump. Inorg. Chem.. 1973, 12, 2506.
Elements of Group 111 141 and the n-butyl analogue, have been obtained by treating the dialkoxychloroborane with hydrogen peroxide in diethyl ether.216A mechanism for the thermal decomposition to boric acid and B(OR), is postulated in which the first stage is homolytic cleavage of the 0-0 bond. A rapid method for determining quantitatively the water content of a large variety of hydrated salts depends upon measuring the volume of ethane liberated when the compound is treated with triethylboron in the presence of small amounts of pivalic acid. One ethyl group is removed per hydrogen according to the equation:217 2Et,B + H,O + 2EtH + (Et,B),O Boric acid forms a stable 2: 1 complex with triquinoyl, which can be isolated as the dipotassium salt (32).218 This supports the formulation of triquinoyl as the dodecahydroxycyclohexane.
2K'
The crystal structure of nickel orthoborate has been deterrnined.,l9 All of the B atoms are triangularly co-ordinated. Heating the mixture T12C03+ Nb,OS+ B 2 0 3to about 1000 "C produces the new multiple oxide TlNbB20,.ZZoThis forms orthorhombic crystals (space group PN21a). Octahedra around Nb are joined at the comers, giving a zig-zag chain in the a-direction. These chains are linked by 2 BO, triangles sharing one 0 atom. The octahedra and triangles form rings around the T1 atom, giving 6 oxygens as nearest neighbours. The following mean bond lengths were found: Nb-0 1.98, T1-0 3.00, B(1)-0 1.35, and B(2)-0 1.36A.
'"V. P. Maslennikov, G. I. Makin, V. N . Alyasov, (U.S.S.R.), 1973, 43, 1954. "' R. Koster and W. Fenzl, Annalen, 1974, 69. 218 219
220
and Yu. A . Aleksandrov, J. Gen. Chem.
T. Goto and M. Nagao, Bull. Chem. SOC. Japan, 1974, 47, 246. J. Pardo, M. Martinez-Ripoli, and S. Garcia-Blanco, Acta Cryst., 1974, B30, 37. M. Gasperin, Acta Cryst., 1974, B30, 1181.
142
Inorganic Chemistry of the Main -group Elements
1.r. and Raman spectra of glasses with the composition Na,O,xB,O, (x = 2 , 3 , 4, 5, 6, or 9) reveal that, as the Na,O concentration rises, an
increasing proportion of the B atoms are four-co-ordinate. A band at ca. 800cm-’ is assigned to rings of the form (33).”l
Kurnakovite, Mg[B,O,(OH),](H,O),,H,O, forms triclinic crystals, of space group P i . The structure contains discrete [B,O,(OH),]’- groups, which share OH groups with Mg(OH),(H,O), tetrahedra to form chains.*” The fifth H,O molecule lies between these chains. Crystallographic parameters have been obtained for TlB,O, (orthorhombic, space group P212121)and TlB,O, (also orthorhombic, the space group is probably Pbca, by analogy with the related K’ Sodium diborate, Na,0,2B203, is triclinic (space group P i ) . The polymeric borate anion forms layers composed of di-pentaborate groups and triborate groups with one non-bridging oxygen, which is a novel feature for d i b ~ r a t e s . ~The ’ ~ B-0 bond lengths were as expected. La,Sr,(BO,), forms orthorhombic crystals (space group Pc2,n; a = 8.78, b = 16.84, c = 7.42 A). The lattice is built up of isolated BO, triangular units (average B-0 distance 1.37 A).z25 Lithium aluminoborate, Li6[A12(B03),],is isostructural with the analogous galloborate, forming triclinic crystals (space group The anionic framework [Al,(BOJ-], contains chains parallel to the (010)-plane, built up of rings formed by 2 A1 tetrahedra and 2 B triangles, interlinked in one direction by two other B triangles. An X-ray study on Pr,Sr,(BO,), (space group P2,Cn) shows the presence of triangular BOi- ions linked to the cations to give a three-dimensional There are two different types of Pr environment; each is co-ordinated to 8 oxygens in a distorted ‘biclinoid’ arrangement. Pr-0 distances are respectively 2.22-2.82 A and 2.47-3.05 A. Three different Sr2+co-ordination polyhedra are found, with co-ordination numbers of 10, 8, and 9, respectively, Orthorhombic MnB,07 belongs to the space group Pcba. The B407 unit A . Bertoluzza, B. Righetti. and S . Schiavina. Atti Acud. n u z . Lincei. Rend. C l a w Sci. jk. mat. nut., 1972, 53, 421. ’” E. Corazza, Acta Cryst., 1974,B30, 2194. 2 2 3 M . Touboul. Cornpt. rend., 1973, 277, C, 102s. 2 2 4 J . Krogh-Moe, Acta Cryst., 1974, B30, 578. z z 5 G. K. Abdullaev, Kh. S. Mamedov. and S. T. Amirov, Soviet Phys. Cryst., 1974, 18, 675. ”‘ G. K. Abdullaev and Kh. S. Mamedov, Soviet Phys. Cryst., 1974, 19, 98. 2 2 7 K. K . Palkina, V. G. Kuznetsov, and 1.. G . Moruga, J . Struct. Chem., 1973. 14, 988.
143 Elements of Group I11 consists of two BO, tetrahedra with one common oxygen atom, each sharing two other 0 atoms with 2 triangular BO, groups; the average distance B-O(tet) distance is 1.473 A, the average B-O(triang.) 1.368 A.228 Direct reaction of M3P208and Na,B,O, (M = Ca or Sr) gives apatite-like Na, (P04)6Bx+zy 02,which contain linear [0-B-01units, phosphates, M9+y with B-0 bond lengths of 1.25 k0.02 A number of i.r. bands have been assigned for the polyborates K[B,O,(OH),] and K,[B60,(OH),] by using partial de~teriation.~,’ The potassium cobalt hexaborate {K,,CO}[B,O,(OH),],,4H20 forms t i clinic crystals of space group C:-PT. The structure contains isolated [B607(OH)6]2a-Sodium triborate, a-Na20,3B20,, is monoclinic (space group P2Jc). The borate anion forms two separate, interpenetrating, infinite frameworks. Each of these consists of pentaborate and diborate groups (in equal amounts).232 Caesium triborate, on the other hand, crystallizes in the orthorhombic space group P212,21. The borate anion forms a threedimensional framework built up from triborate groups.233 Phase relationships have been examined in the system B,O,-K,O-WO,; a congruently melting, ternary compound 3Kz0,3B203,4W03 is formed.234The phase diagram of the PbO-B,03-W0, system has also been reported.235 Potassium borate glasses of the composition Kz0,4Bz03can be crystallized to give a compound Kz0,3.8B203 (i.e. 5K,0,19B20,). The crystal structure of this has been determined; it belongs to the space group C2/c (monoclinic). The polymeric borate anion is three-dimensional, and built from interconnected pentaborate groups, triborate groups, BO, tetrahedra, and BO, Hexalead pentaborate, 6Pb0,5B20,, is triclinic. The structure contains isolated B,,O::- polyanions, which are built up from two diborate groups linked by two BO,
Compounds containing B-S or B-Se Bonds.-A high-temperature reaction (1100 “C) between H2S and crystalline boron produces a transient thioborine molecule, HBS.238A photoelectron spectrum of this was obtained, showing adiabatic ionization potentials of 11.11*0.03, 13.54k0.03, **’
S. C. Abrahams, J. L. Bernstein, P. Gibart, M. Robbins, and R. C. Sherwood, J. Chem. Phys., 1974,60, 1899. ’” C. Calvo and R. Faggiani, J.C.S. Chem. Comm., 1974, 714. 230 G. Heller and A. Giebelhausen, J. Inorg. Nuclear Chem., 1973, 35, 3511. 2 3 ’ E. Ya. Silin’, Ya. K. Ozol, and A. F. Ievin’sh, Soviet Phys. Cryst., 1973, 18, 317. 2 3 2 J. Krogh-Moe, Acta Cryst., 1974, B30, 747. 233 J . Krogh-Moe, Acta Cryst., 1974, B30, 1178, 234 A. G. Bergman, V. L. Volkov, and V. T. Mal’tsev, Russ. J. Inorg. Chem., 1973, 18, 573. 235 V. T. Mal’tsev, A. G. Bergman, P. M. Chobanyan, and V. L. Volkov, Russ. J . Inorg. Chem., 1973, 18, 1764. *’‘ J. Krogh-Moe, Acta Cryst., 1974, B30, 1827. 237 J . Krogh-Moe and P. S. Wold-Hansen, Acta Cryst., 1973, B29, 2242. 238 H. W. Kroto, R. J. Suffolk, and N. P. C. Wcstwood, Chem. Phys. Letters, 1973, 22, 495.
144
Inorganic Chemistry of the Main -group Elements and 15.83 f O . l eV. The absence of vibrational fine structure due to bending motion is interpreted as indicating that all three states of HBS associated with these bands are linear. Another report of the photoelectron spectrum of this species is consistent with the above.239 Microwave spectra at zero field of the J = O-, J = 1 transitions in H' 'B3'S, D1'B3'S, and D"B"S yield nuclear quadrupole constants of -3.72k0.03 ("B) and -7.91 k0.03 ("B) MHz.*" Measurements in a high electric field gave a value of Ipl= 1.298f0.005 D for the electric dipole moments. A near-Hartree-Fock wavefunction for thioborine, HBS, has been used to calculate various molecular properties at the experimental geometry."' These agreed rather well with available spectroscopic data. 1.r. and Raman spectra have been recorded and interpreted for B(SH),, B(SD),, BX(SH)', and BX(SD),, where X = B r or I.*'* All are consistent with the molecules being planar. A CNDO/2 calculation on the BCl,(SH) molecule yields a barrier to internal rotation of 2.18 kcal mol-' (compared to an experimental value of ca. 1 kcal m ~ l - ' ) . ' ~ ~ Gas-phase electron-diff raction measurements on methylthiodimethylborane, Me,BSMe, suggest that the skeleton is probably planar, although values of up to about 25" for the torsional angle about the B-S bond could not be ruled The most important molecular parameters are : B-S 1.779(5), C-S 1.825(4), C-B 1.570(4) A, LBSC 107.2(10)", LSBC(Me) 124.0(8)", and 115.3(6)". The molecular skeleton of B(SMe), was found by electron diffraction to be essentially planar, with r(B-S) = 1.805(2), r(S-C) = 1.825(3) A, and LBSC = 104.5(3)0.245 Pyridine and methyl(methylthio)boranes, BMe,(SMe),-,, form adducts which are more stable than the corresponding NMe, adducts. The acidity of these boranes decreases with an increased number of SMe groups.z46 Photoelectron spectra have been reported for a series of methylthio- and methoxy-boranes Me,-,BX, (X = SMe or OMe).247These were compared and assigned using modified CND0/2 calculations. Substituent effects and chemical shifts (6"B) were consistent with significant 7-contributions to the B-S bond. The complexes BX1,R3PY(X = C1, Br, or I but not F; R = Me, Ph, or Cy; 23y 240
241
242 243 244 245 246
247
T. P. Fehlner and D. W. Turner, J. Amer. Chern. Soc., 1973. 95, 7175. E. F. Pearson, C. L. Norris, and W. H. Flygare, J. Chem. Phys., 1974, 60, 1761. C. Thomson, Chern. Phys. Letters, 1974, 25, 59. M. Fouassier, M.-T. Forel, J . Bouix, and R. Hillel, J. Chirn. phys., 1973, 70, 1518. H. S. Randhawa, Z . phys. Chem. (Frankfurt), 1974, 89, 320. K . Brendhaugen, E. W. Nilssen, and H. M. Seip, Acta Chem. Scund., 1973, 27, 2965. K.Johansen, E. W. Nilssen, H. M. Seip, and W. Siebert. Acta Chem. Scund.. 1973, 27, 30 15. H. Noth and U. Schuchardt, Chem. Ber., 1974. 107, 3104. J . Kroner, D. Nolle, and H. Noth, Z. Naturforsch., 1973, 28b, 416.
Elements of Group 111 145 Y = S or Se) have been prepared.2481.r. spectra and n.m.r. ( R = Me only) spectra were reported. The shifts in u(P-Y) upon co-ordination are very large for nsn-bridging ligands, indeed almost as large as when these ligands act as bridging species. The spectral data on the B-Y bond indicate that this increases in strength as the atomic weight of X increases. Thioboranes PhnB(SR)3-n ( n = 0 , 1, or 2) may be obtained from the interaction of a lead thiolate and the corresponding chloroborane:
Lr., mass, and "B n.m.r. spectra were reported for the compounds with R = Me, Et, or Pr".'49
Boron Halides.-An cab initio MO calculation on BF2, using a nearHartree-Fock atomic basis, predicts a bond angle of 120" and a bond length of 1.22A for the XZ(A,)ground state.'" Similar calculations (using a restricted Hartree-Fock model) on the excited states of BF, suggest that some of these may have very unusual geometries (e.g. angles of 46", 6O0).'" The overlap populations are positive and hence these states are likely to exist (unlike some similar apparent states for NH,). An analysis of the rotational constants of SiF,BF, derived from the microwave spectrum leads to a very large value for the Si-B bond length (2.04*0.03 This is greater than the value expected for a single bond and is consistent with the very low barrier to rotation (1.9k0.8 cal mol-') about this bond. The molecules B4F4 and B4CL have been studied by ab initio SCF methods, using a minimum basis set of Slater The results suggest that there is more .rr-back-donation for B4F4 than for B4CL, although expanded-basis-set calculations may be necessary before such conclusions can be regarded as definite. A relative acidity scale based on the proton shifts of the diethyl etherates of BCl, and BF, has been extended to a number of trifluorovinylchlorob o r a n e ~ . 'The ~ ~ following sequence was observed, with approximate values as shown: BC1, > C,F3BC12> (C2F,),BC1> (C,F,),B > BF, (100)
(92)
(82)
(74)
(63)
These are consistent with a lack of interaction between the .rr-electrons of the trifluorovinyl group and the boron pz -orbital.
"' P. 249
25u 2s1
252 257 2s4
M. Boorman and D. Potts, Canad. J. Chem., 1974,52, 2106. R. H . Cragg, J. P. N. Husband, and A. F. Weston, J . Inorg. Nucleur Chem., 1973, 35,3685. C. Thomson and D. Brotchie, Theor. Chim. Acta, 1973, 32, 101. C. Thomson and D. Brotchie, Mol. Phys., 1974, 28, 301. T. Ogata, A. P. Cox, D. L. Smith, and P. L. Timms, Chem. Phys. Letters, 1974, 26, 186. J . H. Hall jun., and W. N . Lipscomb, Inorg. Chem., 1974, 13, 710. N. Walker and A. J . Leffler, Inorg. Chem., 1974, 13, 484.
146 Inorganic Chemistry of the Main - group Elements Preliminary results of a ”C n.m.r. study of BF, and BC1, complexes with a number of ethers have been reported.255At low temperatures it was possible to detect separate signals for free and co-ordinated ether molecules. The 13C shifts at the a-carbon are to lower field in the complexes, and decrease in the order: THF> E t 2 0> P r 2 0 Bu,O. A b initio calculations of the heats of formation of a series of BF, addition compounds (with, for example, NH,, H 2 0 , F-, CO, C1-, H2S, Ne, or Ar) reflect the trends in the experimental data, where these are available.256 Complexes which are unknown (Ne, Ar, H2S, and CO) all have negative heats of formation, but complex formation is not favoured by the entropy changes. The adduct (tetramethylurea),BF, contains (when prepared in the absence of solvent) some [(tmu),BF,]’BF;, which is detected by n.m.r. experim e n t ~ . ~The ~ ’ mixed halide adducts (tmu),BF,Cl and (tmu),BFCl, are formed when the BF, and BCl, adducts are mixed. The former can be used to generate larger amounts of [(trnu),BF2]+ uia nucleophilic attack of tmu on the adduct, with displacement of C1-. Kinetic studies of the heterogeneous reaction: =ZI
reveal a slowing-down, and even a cessation of reaction, as the reaction progresses, especially at higher temperatures. This may be attributed to an agglomeration of the reaction product at the SrF, s u r f a ~ e . ~ ~ ~ . ~ ’ ~ Thermodynamic data for the negative ions of boron and aluminium fluoride, e.g. MF; and MF,, have been evaluated from effusion mass spectrometric measurements over the temperature range 1100-1 900 K.’“” Electron affinities for BF, and AlF, are 50.7*3 and 53.1 *t3 kcal mol-’, respectively. The influence of excess H’ (from H,SO,) upon the rate of reaction of H,BO,+HF (to produce HBF,) has been interpreted in terms of the following reaction mechanism:261 H,BO,
+ 3HF+
HBF,(OH) + 2H,O (very fast)
HBF,(OH) + H+& (HBF;OH2) (HBFiOH,) + HFk-. HBF,
”’
+ H,O
A. Fratiello, G. A. Vidulich, and R. E. Schuster, J . Inorg. Nuclear Chew., 1974. 36, 9.3. R. M. Archibald. D. R. Armstrong, and P. CT.Perkins, J.C.S. Faraday 11, 1973, 69, 1793. ”’ J . S. Hartman and G. J . Schrobilgen, Inorg. Chew., 1974. 13, 874. ”’ A. Boisselier, F. Caralp, and M. Destriau. Bull. Soc. chim. France. 1Y74, 1233. 2 4 y A. Boisselier. F. Caralp, and M. Dcstriau, Bull. Soc. chirn. France, 1974, 1735. O ‘’ R. D. Srivastava, 0. M. Uy. and M . Farber, J.C.S. Faraday 11. 1974. 70, 1033. ”l M. P. Menon, J . Inorg. Nuclear Chew., 1973, 35, 4183. 776 -
Elements of Group 111
147
Ionization energies of the electronic valence levels of BF, have been obtained by X-ray electron spectroscopy.262 The RbF-RbBF, system is a simple eutectic, with a eutectic composition of 68.5 mole% RbBF,, and a melting point of 442 f2 oC.’63 Complexing of BF, with solutions containing MF, ( M = N b or Ta) gives chiefly a disproportionation reaction yielding M,F;, :264 BF, + MF, 6 BF, MF, + MF; BF, + BF,
+ MF,
M2F;, B,F;
X-Ray diffraction and transition entropy data for the high-temperature phases of NH: and K’BF; have been interpreted in terms of an approximate structure for these systems.26s In this the anions are distributed between two sets of statistically equivalent orientations in the skeleton of the positive ions, in a similar manner to that proposed for univalent metal perchlorates. The crystal structure of Cu(BF,)(PPh,), reveals that the BF; ion is weakly co-ordinated to the Cu via a Cu-F-B interaction.266Relevant structural data are summarized in Figure 21. The Raman spectrum of the complex was recorded and compared with that of CuCl(PPh,),. Characteristic BF; bands were seen at 765 (A, stretch) and 355 cm-’ (E, def.), with a band at 176 cm-’ assigned to v(CuF). The low value of the last agrees with the weak interaction deduced from the Cu-F bond length. An i.r. study of the mixed boron trihalide adducts of carbonyl donors (ethyl acetate and benzophenone) shows that the mixed adducts do indeed possess Lewis acidities intermediate between those of the corresponding BX, ~ystems.’~’ “B and 19F chemical shifts and “B-”F coupling constants of boron trihalide adducts have been shown to behave in accordance with the concept of ‘painvise additivity’.’68 Hard and soft donor atoms yield very different donor-halogen pairwise interaction parameters, which can be diagnostically useful when donor ligands contain more than one possible donor atom. The i.r. and Raman spectra of BX, (X = F, C1, Br, I, or H) complexes of 1,4-diazabicycl0[2,2,2]octane, dabco, suggest that these (dabco)(BX,), complexes have D,, (not D,) Analogous quinuclidine complexes gave spectra which could be assigned on the basis of C1,symmetry. 262
263 264 265
266 267
268 269
V. 1. Nefedov, Yu. V. Kokunov, Yu. A. Buslaev, and M. A. Porai-Koshits, Russ. J. Inorg. Chem., 1973, 18, 637. L. 0. Kilpatrick and C. J. Barton, J. Inorg. Nuclear Chern., 1974, 36, 725. S. Brownstein, J . Inorg. Nuclear Chem., 1973, 35, 3567. K. 0. Stromme, Acta Chem. Scand., 1974, 28A, 546. A. P. Gaughan jun., Z . Dori, and J. A. Ibers, Inorg. Chem., 1974, 13, 1657. J. S. Hartman and R. R. Yetman, Canad. J . Spectroscopy, 1974, 19, 1 . J. S. Hartman and J. M. Miller. Inorg. Chern., 1974, 13, 1467. J . R . Mcdivitt and G . L. Humphrey, Spectrochim. Acta, 1974, 30A, 1021.
148
Inorganic Chemistry of the Main-group Elements
Figure 21 Perspective view of the inner co-ordination sphere of Cu(BF,)(PPh,),. The distances and angles refer to a chemically averaged (Reproduced by permission from Inorg. Chem., 1974, 13, 1657) The vapour-pressure isotope effect of BC1, (loB/llB) as observed by Rayleigh distillation appears to be of the wrong sign according to the theory of isotope effects in condensed systems (that for ”Cl/”Cl is satisfactory, however) .270 1.r. and Raman spectra of polycrystalline BX, (X = C1, Br, or I) at 80 and 18 K were analysed to give values for the lattice vibration wave number^.^^' CNDO molecular wavefunctions have been used to calculate dipolemoment derivatives for BCl,.272These were compared with experimental values from i.r. intensities. The latter set, having all signs negative, was preferred. The reaction of elemental boron with GeCl, gives BCl,+Ge at 550600 “C, BCl, + GeCl, at 600-800 “C, and BCl, + Ge’ chloride at 9001100 0C.273No evidence was found for the formation of BC1 at any stage. Complex formation involving acetic anhydride has been investigated in 27(1
. G. Jancsh. Her. Bunsengesellschuft phys. Chern.. I 9 7 4 78, 63X. 0. S. Binbrek, N. Krishnamurthy, and A. Anderson, J. Chem. Phys., 1974, 60, 4400. 272 R. E. Bruns and P. M. Kuznetsof, J . Chem. Phys., 1973, 59, 4362. 2 7 3 G. M . Gabrilov and V . I. Evdokimov. Russ. J. Inorg. Chern., 1973. 18, 915.
’’’
Elements of Group III
149
liquid SO, Among the compounds isolated were 1:1 adducts with BX,, A K , (X = C1 or Br), and InCl,. SbCl, also gives a 1: 1 adduct. Simple donar-acceptor complexes are indicated (by conductivity measurements, mol. wt. determinations, and i.r. spectra) for the majority of the compounds, but there is evidence for the acetylium ion in the cases of AlBr, and SbCl,. BCl, reacts with a number of chlorides of univalent cations to give tetrachloroborates MBC1,: the degrees of conversion are shown in Table 3 .27s
Table 3 Degrees of conversion into MBC1, Halide KCl RbCl CSCl NMe4C1 NEt,Cl
Solvent CHC1, BCl, 50.0 76.3 72.5 61.1 81.9 85.2 88.9 95.7 91.9 97.2
A convenient synthesis of B,CL, has been reported, employing a novel vapour pump.276 The results of an all-electron a b initio MO calculation predict a staggered (DZd) configuration for B2C14,with a barrier to rotation of 1.48 kcal mol-'. Results for B,F, indicate a similar configuration with a much reduced barrier (0.39 kcal mol-'). Further calculations indicate that B4C1, is more stable with respect to four BCl units than is B,F, to four BF.277 The standard enthalpies of formation of o - and p-tolyldichloroboranes have been determined from a thermochemical study of their oxidative hydroly~es."~Boron-carbon bond energies were calculated from these: o-MeC6H4BCl, 463 f 10, p-MeCsH4BClz 504* 10, and PhBC1, 508* 10 kJ mol-', for E(B-C). The value for the para-isomer is essentially identical to that for the PhBC12,but the steric effects of the o-Me group are such as to lead to a significant decrease in E(B-C) because of twisting of BCl, out of the ring plane and consequent loss of pm-p,, character in the B-C bond, Studies of the interaction of BBr, vapour with boron show that the reported transport of B in BBr, vapour is due to thermal dissociation of the latter.279 Raman spectra of mixtures of BBr, and PBr, contain bands characteristic of PBr: and BBr;.28" An emission spectrum of BI in the region 5700-6215 A has been 274
275
276 277 278 279
K. C. Malhotra and D . S. Katoch, Austral. J . Chem., 1974, 27, 1413. K. V. Titova, I. P. Vavilova, and V. Ya. Rosolovskii, Russ. J . Inorg. Chem., 1973, 18,597. J . P. Brennan, Tnorg. Chem., 1974, 13, 490. M. F. Guest and I. H. Hillier, J.C.S. Faraday I I , 1974, 70, 398. A. Finch, P. J. Gardner, N. Hill, and K. S. Hussain, J.C.S. Dalton, 1973, 2543. B. A. Savel'ev, V. A. Krenev, and V. I. Evdokomov, Russ. J . Inorg. Chem., 1973,18, 748. M.-C. Deneufeglise, P. Dhamelincourt, and M. Migeon, Compt. rend., 1974, 278, C, 17.
150
Inorganic Chemistry of the Main - group Elements observed,**' which can be assigned to the a311'-,X'C' system. Flash photolysis of BI3 gives two band heads (3489.3, 3491.0A) due to the a 'II + X'c' transition of BI.
Boron-containing Heterocycles.-The enthalpies of adduct formation between pyridine, 2-picoline, 4-picoline, or 2,4,6-collidine and a number of heterocyclic boron derivatives (2-Br- or 2-organo- 1,3,2-dihetero-borolans, -borinans, and -boroles) have been measured.282The presence of Br greatly increases the Lewis acidity of the B atom. A number of methods have been devised for the preparation of the new compound H,B(NMe,),Al(BH,),, e.g. the reaction of excess B,H, with Et,O solutions of Al(NMe,),, HAI(NMe,),, or [H,B(NMe),],AlH. Characterization of the compound leads to the postulated structure (34).'"
(34)
Tris(mono-n-alkylamine),B,H, adducts decompose thermally by the following scheme, via p -monoalkylaminodiboranes(6), with the final formation of NN'N"-trialkylborazines, polymeric solid boranes, (BH),, and H2:284 3 3(B,H9,3NHZR) + (35) +- (HZB-NRH), (35) +-2(HBNR), 3
- (BHZNHR), -+
6 +n (BH), + 12H2
(HBNR), + 3Hz
A series of N- or B-functional derivatives of 1,2,4-triaza-3,5-diborolidines (36), where R', R 2 = H , Me; R 3 = H , Me, or B(NR,),; R 4 = M e , C1, R'
N N '
2x 1
/R2
I
\
J . Lebreton. J . Ferran, A. Chatalic, D. Iacocca, and L. Marsigny, J. Chim. phys., 1974, 71, 5x7. '" M . Wieber and W. Kiinzel, Z. anorg. Chem., 1974, 403, 107. zx3 P. C. Keller, J . Amer. Chem. SOC., 1974, 96, 3073. 2x4 A. F. Zhigach, V. T. Laptev, A. B. Petrunin, V. S. Nikitin, and D. B. Bekker, Russ. J. Inorg. Chem., 1973, 18, 1249.
151 Elements of Group I11 Br, NMe2, or SMe, have been p~epared."~A typical reaction leading to such a system is:
' = SMe) 2B(SMe),+ MeNHNHMe+ MeNH2+ (36; R' = R2= Me, R Photoelectron spectra have been reported and largely assigned for five tetra-azadiborines (37; X = Me, C1, MeS, MeO, and MezN).286Orbital energies calculated using the C N D 0 / 2 approach agree quite well with the observed ionization energies.
Two more efficient methods for the synthesis of bis(F-dimethylamino)triborane(9) (38) have been described, viz. the reaction of Me,NHBH,NMe,BH, + K (in ether solvents), to give KMe,NBH,NMe,BH,; treatment of this with excess B2H, forms the desired Alternatively, HB(NMe,), + B2H, forms this species directly. Detailed "B n.m.r. spectroscopic studies have been made of the compound and of the courses of a number of its reactions. A new heterocyclic system (39) containing B and Sn has been prepared, thus: Et,NB(C=CMe), + Me,SnH, + (39). The "B chemical shift is at -33.7 p.p.m. from BF,,OEt, at 32.1 MHz, and v(C=C) bands were seen at 1590, 1560 cm-'.288 The (1-methy1borinato)cobalt complex (40) may be prepared by the A number of other reaction of the known (41) with diphen~lacetylene.~~~ closely related complexes have also been de~cribed.'~'
I
I co
phm:: I
Ph
285
**' 287 28R
289
Ph HN/~\NH
I
MeSi,
I
,SiMe, N H
D. Nolle, H. Noth, and W. Winterstein, Z. anorg. Chern., 1974, 406, 235. J. Kroner, D. Nolle, H. Niith, and W. Winterstein, Z. Naturforsch., 1974, 29b, 476. P. C. Keller, J: Amer. Chem. SOC.,1974, 96, 3078. €3. Wrackmeyer and H. Noth, Z. Naturforsch., 1974, 29b, 564. G. E. Herberich and H. J. Becker, Z. Naturforsch., 1973, 28b, 828. G. E. Herberich and H. J. Becker, Z. Naturforsch., 1974, 29b, 439.
152
Inorganic Chemistry of the Main -group Elements Phenyldichloroborane reacts with (Me,SiNH), to give (42), and related species, depending upon the ratio of the reactants.291 Previous X-ray data (J. G. Haasnoot, G. C. Verschoor, C. Romers, and W. L. Groeneveld, Acta Cryst., 1972, B28, 2070), which indicated alternating B-N bond lengths in hexachloroborazine, have been reinterpreted, in conjunction with semi-empirical MO calculations.292The data were shown to be consistent with the presence of a regular hexagonal ring. Use has been made of a strong substituent effect in borazine chemistry to produce 2,4-dichloroborazine in a specific, two-step ~ y n t h e s i s . ~The ' ~ first stage involves the reaction of Cl,B,N,H,+NMe,H to produce only C1,(NMe2)B,N3H,, which subsequently reacts with B,H, in E t 2 0 to form HCl,B,N,H,. A modification of the standard C N D 0 / 2 MO calculation, in which pairs of atoms associated with the same or different molecules are differentiated, leads to reasonable results for n-.rr-type molecular complexes.294It was suggested that benzene-borazine (stabilization energy 2--5 kcal mol-') and borazine-borazine (5-18 kcal mol ') can exist in the ground state, the molecules being arranged symmetrically in parallel planes. The unsymmetrical B-substituted borazine derivatives H(X)(Y)B,N,H,, where X = C1, Y = OCN; X = C1, Y = CN; X = CN, Y = OCN; X = OCN, Y = OCN; X = CN, Y = CN, have been prepared by the reaction of the appropriate B-substituted chloroborazine with an Ag' It was found that H atoms in B-substituted borazines, unlike those in H3B3N3H3,are inert to attack by an Ag' salt, giving the first evidence for a substituent effect in borazine chemistry. Considerations of magnetic susceptibilities and 'H n.m.r. data suggest that B-tribromo-, B -trifluoro-, and B -trialkoxy-borazines can be considered as aromatic Their aromatic characters, however, are in the sequence: B-tribromo- > B -trialkoxy- > B -trifluoro-derivatives. Comparison of spin-spin coupling constants through -5, 6, or 7 bonds between protons in benzene derivatives and borazines indicates that there is a relatively weak transmission of spin density via the presumed n-electron system of bora~ine.*~' 'H n.m.r. spectral data have been reported for hexamethylborazine, B monoethylpentamethylborazine, BB '-decamethylbiborazine, and B -pentamethylphenylpentamethylb~razine.~~~ A synthesis of deuterium-labelled hexamethylborazine, with CD, groups
'" H . Noth,
W. Tinhof, and T. l a e g e r . Chem. Ber., 1973, 107, 3 1 13. M . S. Gopinathan, M . A. Whitehead, C . A . Coulson, J. R. Carruthers. and J . Kollett, Actu Cryst., 1974, B30, 731, 1650. zy3 0. T. Beachley jun., and T. R. Durkin, Inorg. Chem., 1974, 13, 1768. 294 F. Grein and K. Weiss, Theor. Chim. Acta, 1974, 34, 315. 2 y 5 0. T. Beachley jun., Inorg. Chem., 1973, 12, 2503. 29h G. Cros a n d J.-P. Laurent, J . Chim. phys.. 1974, 71, 802. 297 J . B. Rowbotham and T. Schaeffer, Canad. J . Chem., 1974, 52, 489. '" J. L. Adcock and J . J . Lagowski, J. Organometallic Chem., 1974, 72, 323.
'*
Elements of Group I11 153 attached to the B, has been described,299and a pyrolysis carried out at 500 "C. The products were investigated mass-spectrometrically, showing that H-containing methanes predominate over those containing D. This indicates that the rate of homolytic rupture of N-C bonds is greater than that for B-C bonds. A number of (substituted borazine)chromium tricarbonyl complexes have been prepared.30"The chief change in the vibrational spectrum of the ligand upon complexation is a decrease in the wavenumbers of the band associated with B-N stretching, e.g. in (Me,N,B,Me,Ph)Cr(CO), this is at 1371 cm-', compared to 1423 cm-' in the free ligand. N-Methyltetrahydro-2,1 -borazarene may be partially dehydrogenated to N-methyl-2,l-borazarene (43). This could only be identified massspectrometrically, as it is highly reactive, being quite unlike benzene, and more akin to a polarized butadiene derivative.,"'
Tris(amin0)boranes react readily with aliphatic NN'-dialkyldiamines in an inert solvent, giving a 2-amino- 1,3,2-diazaboracycloalkane(44): (Me2N),B + (RHN)2(CH2),-+ 2Me,NH+ (44) ( R = M e or Et). When R = H , however, a polycycliborazine (45) results, e.g.302 (Me,N),B
+ (H2N),(CH2),-+3Me2NH+(45)
173,2-Diazaborolines (46) may be prepared by the dehydrogenation (using Pd/C) of saturated derivatives, R' = Me, R2= Ph or CMe,, or R' = H, R2= Ph.,03 This heterocyclic system is isoelectronic with the cyclopentadienide ion, and some data ( e . g U.V. spectra) suggest that there are comparable degrees of electron delocalization in the two cases. The same conclusions follow from a consideration of their H e (I) photoelectron A new boron-containing heterocycle, 1,173,3-tetramethyl-173-diazonia2,4-diboratocyclopentane (47), has been prepared by the reaction of 299
30" 'O'
'02
303 304
N. A . Vasilenko, A . S. Teleshova, and A . N . Pravednikov, J . Gen. Chem. (U.S.S.R.),1973, 43, 1114. J . L. Adcock and J . J . Lagowski, Inorg. Chern., 1973, 12, 2533. H. Wille and J . Goubeau, Chern. Ber., 1974, 107, 110. R. H. Cragg and M. Nazery, Inorg. Nuclear Chem. Letters, 1974, 10, 481. K. Niedenzu and J . S. Merriam, Z. anorg. Chern., 1974, 406, 251. J . Kroner, H. Noth, and K. Niedenzu, J. Organornetallic Chern., 1974, 71, 165.
154
Inorganic Chemistry of the Main -group Elements HN
I
HC=CH
i \
R1-vM I
R2
bis(trimethy1amino)boronium iodide with Na-K alloy in 1,2dimethoxyethane.'"' I.r., 'H and "B n.m.r., and mass spectral data were reported.
\
I
R1
N-CH2R'
H,B -NMe,
I
Me
(47)
(48)
The amine-boranes of 3,4-dihydro-2H- 1,3-benzoxazines are unstable t o heat, producing 4H- l-oxa-3-azonia-2-boratonaphthalenes,i.e. (48), where R ' = M e O , R Z = P h , PhCHz, or H.306 A new five-membered heterocyclic species containing Si and B has been prepared by the sequence of reaction^:^"' Ph,Si-SiPhz Ph,Si-SiPh,
I
I
Ph,Si-SiPh,
I . SiPh, I A PhzSi I Li
t Li
Ph'Si-SiPh, C12BNMe2+
Ph,Si 'B'
I
SiPh, NMe,
The crystal structure of (49) has been determined.308The crystals are orthorhombic, belonging to the space group Pna 2 , . The following bond lengths were reported: B-C 1.632(8), B-0 1.506(7) and 1.556(8), N-0
")'
B. R. Gragg and G. E. Ryschkewitsch, J. Amer. Chem. Soc.. 1Y74. 96, 1717. E. Lyle and D. A. Walsh, J . Organornetallic Chem., 1974, 67,363. E. Hengge and D. Wolfer, J. Organometallic Chem., 1974, 66,413. S. J . Rettig, J . Trotter, and W. Kliegel, Cunad. J. Chem., 1974, 52, 2531.
'"'R. '07 'Ox
Elements of Group I11 155 1.409(5), C-0 1.378(9), and C-N 1.467-1.509(7-10) A. The ring possesses a distorted, half-chair conformation. Mass spectra of numerous boron-chelate complexes of pyridines and quinolines (five-membered chelate rings) and their N-oxides (six-membered chelate rings) have been recorded.309 By analogy with the P-diketonates, the products (50) that result when (acy1amino)dialkylboranes RiBNHCOR' form complexes are considered as chelates of the ligand N-acylamidine."" Spectroscopic data have been presented and reactions described in which both retention and degradation
of the chelate ring occur. Acetic acid can be used to replace one of the R groups on boron by an OC(=O)Me group, with preservation of the chelate structure. Syntheses and some characteristic reactions have been reported for some derivatives (51); when M = Si, R' = Me, Et, Pr, or Ph, R2= Me; or M = Sn, R' are as before, R2= Bu or Ph.3" BB -Bis-(p-fluoropheny1)boroxazolidine(52) forms orthorhombic crystals,
space group P2,2,2,."' The five-membered ring is in the half-chair conformation, with the following (mean) bond lengths: B-N 1.652(4), B-0 1.471(4), C-N 1.491(4), and C-0 1.418(4)A. A number of new five- and six-membered heterocycles have been pre' ~ are pared, e.g. (53); these are formally cyclized amino-acid b o r a n e ~ . ~All air-stable, volatile solids, characterized by the usual physical methods. The crystal structure of (54)has been determined.314It is orthorhombic, belonging to the space group Pnrna, and the B-0 and B-C distances are 1.394 and 1.537 A, respectively. ?'" ?"'
?"
3'1 314
E. Hohaus and W. Riepe, Z . Naturforsch., 1973, 28b, 440. V. A. Dorokhov, L. I . Lavrincivich, M. N. Bochkareva, V. S. Bogdanov, and B. N. Mikhailov, J. Gen. Chem. (U.S.S.R.), 1973, 43, 1106. A . B. Goel and V. D. Gupta, J. Organometallic Chem., 1974, 77, 183. S. J . Rettig and J . Trotter, Acta Cryst., 1974, B30, 2139. N. E. Miller, Inorg. Chem., 1974, 13, 1459. F. Zettler. H. D. Hausen, and H . Hess, Acta Cryst., 1974, B30, 1876.
Inorganic Chemistry of the Main-group Elements
156
/ O V 0
Substituted derivatives of 2-phenyl- 1,3,2-dioxaborolans undergo electron-impact-induced rearrangements, giving hydrocarbon ions (detected mass-spectrometrically) .315 The compound (55) is produced as the major species from a gas-phase reaction of 1,l-dimethyldiborane + 0,.3'" It has been characterized by a
0-0 (55)
variety of physical techniques, which suggested that the unexpected stability of the molecule may be due to partial aromatic character. The related compound containing only one Me group is produced by the reaction of methyldiborane and 0, above 150 "C."' Semi-empirical MO calculations on H,B,O, agree with some experimental data which indicate that the preferred structure is (56) rather than (57).31* For the sulphur analogue (X = H, Pr", or Br) the calculated energy levels are close to those found from their electronic spectra. H
HB
/8\ \A/
0 0 0
H
Similar calculations on these types of ring system (both B-0 and B-S) suggest that there is a high degree of conjugation in all cases.319Surprisingly, the degree of conjugation was found to be similar for both types, although this may not be a significant result at this level of approximation. 2-(Trimethylsi1oxy)- 1,3,2-dioxaborolans and -borinans are formed by cleavage of corresponding trialkyl- tin or -germanium derivatives by
'Ih 317 71H
'Iy
H . Cragg. J . F. J . Todd, and A. F. Weston. J. Organornetallic Chem.. 1974, 74, 385 Barton and J . M. Crump. Inorg. Chem., 1973, 12, 2252. Barton, J . M. Crump, and J . BLWheatley, J. Organornetallic Chem., 1974, 72, C1. Zahradnik, Z. Slanina, and P. Carsky, Coll. Czech. Chem. Comrn., 1974, 39, S7. 0. Gropen and P. Vassbotn, Acta Chern. Scand., 1973, 27, 3079. R. L. L. R.
Elements of Group 111
157
Me,SiCl. The products are ( 5 8 ) , where R = -CMe2-CH2-CHMe-, -CMe,-CMe,-, -CH,-CH,-CH,-, or -CH2-CHMe-.320 Reactions producing (59) (with X = H, R = CH,CH, or CMe2CH2CHMe;
X=SiMe,, R=CH,CH,) and (60) (with the same X and R) have been rep~rted.~” The compounds (61; R = Me or Bu; X = CMeKHzCHMe, CMe2CMe2, or CHMeCH,) have been prepared from the dialkyltin oxide, H3B03,and the
(61)
appropriate glycol.322A number of spectroscopic properties suggest that they are dimeric. A large number of 2-substituted 4H-1,3,2-benzodioxaborinshave been prepared by a number of different reactions, e.g.:323
Several examples of (62), (63); and (64) have been d e s ~ r i b e d . ~ ~ ~ , ~ * ~ Pure samples of the cyclic compounds (BSX),, where X = C1, Br, or I, have been prepared in the absence of organic solvents by the following reactions: (BSCI),, dissolution of (BSSH), in liquid BCl,; (BSBr),, action of H,S on liquid BBr,; (BSI),, passing H,S over solid BI,.3’6 They were
(62) 320
3 2’
”* 323
324
325 326
(63)
(64)
S. K. Mehrotra, G. Srivastava, and R. C. Mehrotra, Synth. React. Inorg. Metal-org. Chem., 1974, 4, 27. G. Srivastava, J . Organometallic Chem., 1974, 69, 179. S. K. Mehrotra, G. Srivastava, and R. C. Mehrotra, J . Organometallic Chem., 1974, 65, 367. R. H. Cragg and M . Nazery, J.C.S. Dalton, 1974, 162. R . H. Cragg and M. Nazery, J.C.S. Dalton, 1974, 1438. B. Asgaroulardi, R. Full, K.-J. Schaper, and W. Siebert, Chem. Ber., 1974, 107, 34. R. Hillel. J . Bruix, and M.-T. Forel, Bull. SOC. chim. France, 1974, 83.
158 Inorganic Chemistry of the Main- group Elements characterized by X-ray powder-diffraction, “B n.m.r., i r . , and Raman spectra. Some vibrational assignments have been made, and also for (BSSH), and (BSSD),. Triphenylborthiin (65) possesses considerable stability associated with the ring structure, as revealed by a comparison of its mass spectrum with that of 2,4,6-triphenyl- 1,3,5-trithian. It is that this could possibly be due to charge delocalization in the borthiin ring.
PhB,
,BPh S
Metal Borides.-Chemical and ESCA studies on hydrogen adducts of cobalt and nickel borides are consistent with the formulations (CozB),H3 and (NizB)zH,.328 The structures of CeCo,B, Ce3CollB4,and Ce2C07B3are built up from layers of composition CeCo5 alternating with 1, 2, or 3 layers of composition C ~ C O ~ B ~ . ~ ’ ~ The new ~ - b o r i d e sM,Re,B (M = Z r or Hf) and Hf90s4B have been prepared and identified.”’ IrB--1.35 has a crystal structure that may be described in terms of puckered layers of B and puckered double layers of Ir which also contain B atoms in trigonal-prismatic holes. There is no three-dimensional B network.331 Biborides of holmium and thulium have been prepared from the elem e n t ~They . ~ ~belong ~ to the same class of structures as AlB,. The structures of HoCozB2,PrCo,B,, and Y bCo,Bz have also been determined.333 is The crystal structure of ‘BeB3’, shown analytically to be BeB3.05+0.05, hexagonal. The lattice structure is very complex, although based on icosahedral B,, The new complex ternary borides ThMB,, with M = Mo, W, V, or Re, have been obtained and shown to be isotypic.”’ A band model for the mechanism of conduction of electricity in EUB, and YbB, has been 127 ?ZX
’” 330 11 I
171
333 314
R . H. Cragg and A. F. Weston, J.C.S. Chem. Comm., 1974, 22. P. C. Maybury, R. W. Mitchell, and M . F. Hawthorne. J.C.S. Chem. Comm.. 1973. 534. Yu. B. Kuz’ma and N. S. Bilonizhko. Societ Phys. Cryst., 1973, 18, 137. P. Rogl a n d H. Nowotny, Monatsh., 1973, 104, 1497. T. Lundstriini a n d L.-E. Tergenius. Acra C‘hem. Scund., 1973, 27, 3705. J . Bauer and .I. Debuigne. Compt. rend.. 1973, 277, C, 851. P. Rogl, Monatsh., 1973, 103, 1623. R.Mattes, H. Neidhard, FT. Rethfeld. and K. F. Tebbe. Inorg. Nuclear Chem. Letters, 1973, 9, 1021.
335 136
P. Rogl and H. Nowotny, Monatsh., 1974, 105, 1082. J. B. Goodenough, J.-P. Mercurio, J. Etourneau, R. Naslain, and P. Hagenmuller, Compt. rend., 1973. 277, C, 1239.
Elements of Group I11
159
Electron-beam microanalysis shows that the homogeneity range of the non-stoicheiometric phase EUI-xB6extends from x = 0 to x = 0.10.337 'Erbium hexaboride' is in fact Er,&&.,B6, having the CaB6 The intra-octahedral B-B distance is 1.751k0.039 A,with the shortest Er-B distance 1.622 f 0.008 A. Magnetic measurements have been reported for the 7-borides Ir,,-,Fe, B6 (x = 8-15) and for solid solutions Co,-,FeB, (Ni, Co)& and (Ni, Fe)3B.339 Entropies of fusion have been measured for Zro6Yo,B,,, ErB1,, and ~JB,.~"' Aggregates of single crystals of CUB,, have been produced by cooling Cu-B mixtures from 1500°C to room temperature.341 They are rhombohedral, with a structural unit Cu4.,BIo5. Crystals of copper boride have a variable composition, depending on the temperature of crystallization, ranging from CUB,^.^ at 1700 "C to CUB^^.^ at 1300°C.342
2 Aluminium General.-The species M,Al (M=Gd, Tb, Dy, Er, or Tm) are metamagnetic, and can be divided into two classes. The first 3 possess a NCel temperature of ca. 5 0 K , the remainder having one of only a few K.343 Two new intermetallic phases containing A1 have been reported, UzCu9A1and UCu3.,Al,.,; both are derived from the binary phase U C U ~ . ~ " ~ Crystals of the phase ZrFe,.,Al,., belong to the space group 14/mcm, with a = 8.37, c = 9.98 A.345 A study of the Li-A1 phase diagram has revealed the existence of another phase, Li3A1,.346This may be isolated and shown to form rhombohedra1 crystals, of space group ~ 3 m . The structures adopted by the binary compounds of the Group I or I1 metals with elements from Groups 111-VI, the so-called Zintl-phases, have been reviewed, and the bonding in such species has been discussed in terms of the transition between metallic and ionic bonding.'"' The A1 K a and K@1,3X-ray emission spectra of a number of compounds have been reported, viz. alumina, microcline, kyanite, cryolite, A1F3,AlCl,, topaz, and A1 acetylacetonate and 8-hydroxy-quinolinate, as well as for the '" K. Schwetz and A. Lipp, J. Less-Common Metals, 1973, 33, 295.
-'''M. C. Nichols, 33y
"')
R. W. Mar, and Q. Johnson, J. Less-Common Metals, 1973. 33, 3 17.
R. Sobczak, Monatsh., 1974, 105, 1071.
R. W. Mar and N. D. Stout, High Temp. Sci., 1974. 6, 167. I . Higashi. Y. Takahashi, and T. Atoda, J. Less-Common Metals, 1974, 37, 199. '42 J.-P. Diton, G. Vuillard, and T. l.u,ndstrom, Compt. rend., 1974, 278, C, 1495. 117 B. Barbara. M.-F. Rossignol, and E. Siaiid. Compf. rend., 1974, 278, €3, 513. 344 Z. Bla5ina and A. Ban. Z . Naturforsch.. 1973, 28b, 561. 745 G. Athanassiadis, M. Dirand, and L. Rimlinger. Compt. rend., 1973, 277, C, 915. "'K.-F. Tebbe, H. G . von Schnering, B. Riiter. and G. Rabeneck, Z. Naturforsch., 1973, 28b, 600. 347 H. Schafer, B. Eisenmann, and W. Muller, Angew. Chem. Internat. Edn., 1973, 12,694. 34 1
160
Inorganic Chemistry of the Main-group Elements
metal it~elf.~"" The relative intensities of the two peaks can be related to bond length and degree of ionic character (Figure 22), while it was also proposed that the fine structure of the K/31,3peak may be due to varying A1 3 p participation in different MO's. Binding energies have been determined for a number of A1 (Al2p, 2s), 3d5,2,3 p 3 d , and Tl(T1 4f7,2,4d5,,) compounds using Ga(Ga 3p312, 3 p 1 A 5193 \
t I
I
I
I
I
1.4
1.6
1.8
2.0
2.2
Intensity ratio
(kp!Ka) ./.
Figure 22 Correlation between the KPIKa peak intensity ratio and the Al0 bond length (Reproduced from J.C.S. Dalton, 1974, 901) Relative chemical shifts were found to be X-ray p.e. proportional to the ratios of the average ionic radii of the metals. A1 may be determined quantitativery by the addition of excess edta, with back titration using Cu" sulphate rather than the Zn solutions used previously.35oN-Salicylidene-2-amino-3-hydroxyfluorenemay be used as a reagent for the luminescence determination of Al."' Aluminium Hydrides.-K[AlMe,SiH,] decomposes to give K[AlMe,H]. The crystal structure of the latter shows that isolated tetrahedral anions are present, with r(A1-H) = 1.730(57),r(A1-C) = 1.995(6) Forms of AlH, soluble in Et,O have been prepared for the first time, by the action of BeCl,, ZnCI,, or H 2 S 0 4on LiAIH,."' The standard enthalpies of formation of some trialkylamine-alanes have been determined.354 C . J. Nicholls and D. S . Urch, J.C.S. Dalton. 1974, 901. G. E. McGuire. G . K. Schweitzer, and T. A. Carlson, Inorg. Chern., 1973. 12, 2450. "') S. Murate, G. Nakagawa, and K. Kodama, Japan Analyst, 1974, 23, 242. "' N. N. Grigoryev, P. Kh. Ioannu, and K. P. Stolyarov, Vestnik Leningrad. Uniz;., Fiz. Khint., 1973, 119. 3 5 2 G. Hencken and E. Weiss. J. Organometak Chern., 1974, 73, 35. "' E. C. Ashby. J. R. Sanders, P. Claudy, and R. Schwartz, J. Arner. Chern. SOC., 1973, 95, 6485. "' K . N. Sernenenko, A. P. Savchenkova, and B. M. Bulychev, Russ. J. Inorg. Chem., 1973, 18, 1251.
Elements of Group I11
161
A detailed study of the reaction of LiAlH, and NaAlH, with BeC1, revealed no evidence for the previously reported Be(AlH,),.355 The interaction of MgC1, and LiAlH, in Et,O yields the following new complex hydrides: Mg(AlH,),,LiAlH, and LiA1H,,3Mg(AlH4)2,nEt20.356 Higher halides of Mo and W can be reduced in high yield in NaAlH, melts, giving a convenient and safe procedure for preparing MoII and W" chlorides and Ca(AlH,), and Mg(AlH,), react with primary amines or organic nitriles, at amine or nitrile/alanate ratios of 3:1, to give mixed polyiminocompounds with -AlH-NRand -M-NR(M = Ca or Mg) An extremely detailed vibrational spectroscopic study has been made of Al(BHJ3 and Al(BD,), (gas, solid, matrix-isolated i.r., liquid, solid Raman).359The data were consistent with a prismatic structure (D3,,),and all 23 fundamentals were assigned. Low-temperature thermal analysis of Al(BH,),-arene (arene = benzene, toluene, 0- and p-xylene, or durene) systems shows that 1: 1 adducts are formed in all cases.36o Direct fluorination of M,AlH, (M = Li or Na) gives high yields of M3A1F6, free from MF and AlF, c~ntamination.~~' AlH, and BeCI, in Et,O react according to the following BeC1, + AlH, + H,AlCl + HBeCl HBeCl+ AlH,
+ BeH,
+ H2A1C1
A number of diethyl ether-dihalogenoalane adducts have been prepared and characterized by X-ray powder diffraction studies. The standard enthalpy of formation of HAlCl,,OEt, was calculated to be -774.29 kJ m~l-'.~~~
Compounds containing Al-C Bonds.-The crystal structure of Rb[AlMe,] reveals that the anion has distorted tetrahedral geometry, with two independent CAlC angles of 106" and 115".364 Similar studies on K[A1,Me6F],C6H6 show that the anion contains a linear, symmetric Al-F-A1 bridge, with r(A1-F) = 1.782(2) Gas-phase electron diffraction has been used to determine the molecular 35s
3s6
357
358 3s9
""
361 362 363
364
36s
E. C. Ashby, J. R. Sanders, P. Claudy, and R. D. Schwarz, Inorg. Chem., 1973, 12, 2860. K. N. Semenenko, B. M. Bulychev, and K. B. Bitsoev, Vestnik Moskou, Uniu., Khim., 1974, 74. W. C. Dorman and R. E. McCarley, Inorg. Chem., 1974, 13, 491. S. Cucinella, G. Dozzi, and A. Mazzei, J. Organometallic Chem., 1973, 63, 17. D. A. Coe and J. W. Nibler, Spectrochim. Acta, 1973, 29A, 1789. K. N. Semenenko, 0. V. Kravchenko, and I. I. Korobov, Doklady Chem., 1973, 211, 549. S. D. Arthur, R. A. Jacob, and R. J. Lagow, -1. Inorg. Nuclear Chem., 1973, 35, 3435. E. C. Ashby, P. Claudy, and R. D. Schwartz, Inorg. Chem., 1974, 13, 192. K. N. Semenenko, V. N. Fokin, A. P. Savchenkova, and E. B. Lobkovskii, Russ. J. Inorg. Chem., 1973, 18, 926. J. L. Atwood and D. C. Hrncir, J. Organometallic Chem., 1973, 61, 43. J. L. Atwood and W. R. Newberry, J. Organometallic Chem., 1974, 66, 15.
162 Inorganic Chemistry of the Main -group Elements structure of (Me2A1Cl),."""The Al-C bond is significantly shorter than the Al-C(termina1) bond in (Me,Al),, and the A1-Cl bond significantly longer than the Al-Cl (bridge) bond in (AlC13)2. Electron-diffraction data on Me,A1(C5H,) were unable to distinguish between four possible molecular models (see Figure 23)."' CNDO/2 calculations, however, suggested a preference for (I), with a barrier to internal
I
I
m
IJL
Figure 23 Molecular models of Me,Al(CsH,) (Reproduced by permission from Acta Chem. Scand., 1973, 27, 3735) rotation of the C,H, ring 5 5 kcal mol-I, and a barrier to exchange of Me groups == 10-20 kcal mol- I . '7A1n.q.r. spectra have been reported for a wide range of monomeric and These have been satisfactordimeric A1 species Me,AIX and (R'R2A1X)2.36" ily analysed in terms of a simplified MO theory. [(C,H,)(CsH4)M~H]2A1,Me5 contains C,H, groups that are h'- to the Mo, and which are also involved, uia the unique C atom, in multicentre bonding to 2 A1 atoms.36yThe third A1 is probably concerned in a Mo-HAI(Me,)-H-Mo bonding unit. Ethylaluminium dibromide with 'H substituted in either the methylene or methyl groups has been prepared by treating A1 powder with a little bromine and either CH,CD,Br or CD,CH,Br."" K. Brendhaugen. A. Haaland, and D. P. Novak. Acta Chem. Scand.. 1071. 28A, 35 A . Drew and A . Haaland. Acta Chem. Scund., 1973, 27, 3735. - I h X M . .I. S. I k w a r . D . B. Patterson. and W. I. Simpson. J.C.S. Dalton. 1973, 23x1. "'' S. J. Rettig. A . Storr. B . S. Thomas, and J. Trotter. Acta Cryst., 1974. B30, 666. "" G. Sonnek and H. Reinheckel, Z . Chern.. 1973, 13, 191. ""
'" D.
Elements of Group 111 163 N.m.r. spectra of the dimethylaluminium-t-butyl titanate system are consistent with the exchange reaction:37* 2Ti[OCMe3], + A1,Me6 + (66) + 2TiMe[OCMe3I3 Diethylaluminium dimethylamide and ethanethiolate, Et,AlX (X = NMe, or SEt), react with diketen, via acyl-oxygen bond cleavage and a 1,3hydrogen shift, to give the chelates (67; X = NMe, or SEt).372 CMe,
I
Me
\
c
Me,
A new synthetic route to bis(dialkyla1uminium) oxides has been developed, involving the condensation of lithium dialkylaluminates with dialkylaluminium Trimethylaluminium and ferrocenylmercury chloride (FcHgC1) react to give a compound formulated as F~Al,Me.,cl.~~~ An unambiguous assignment of the structure was not possible. The vibrational spectra have been recorded and assigned for Me2M(OOPX,) (M=Al, Ga, In, or T1; X = F or Cl).375 4
Compounds containing GI-N or AI-P Bonds.-A set of force constants has been calculated for H,Al- and D3Al-NMe, which reproduce the observed vibrational Electron-diffraction data for Cl,AlNH3, assuming a staggered CJuconformation, may be analysed to give the following molecular parameters: r(A1-N) 1.996~0.019,r(A1-C1) 2.100*0.005 A, and LClAlCl 116.3* 0.4°.37'The Al-N bond length is indicative of strong bonding. The thermal stabilities of Et,XAl-NHMe, and Et,XAl-NH,Bu' follow the sequence X = Et < Cl< Br< I.3781.r. and n.m.r. data have been related to this order, and they show that the adduct stability is chiefly a function of the negative charge density at the a - C atoms. 37'
L. S. Bresler, 1. Ya. Podubnyi, T. K . Smirnova, A. S. Khachaturov, and I. Yu. Tsereteli,
372 373
Doklaily Chem., 1973, 210, 45 1. K. Urata, K . Itoh, and Y. Ishii, J. Organometallic Chem., 1973, 63, 11. N. Ueyama, T. Araki, and H. Tani, Inorg. Chem., 1973, 12, 2218. J. L. Atwood, B. L. Bailey, B. L. Kindberg, and W. J. Cook, Austral. J. Chem., 1973, 26,
374
375 376 377 378
2297. B. Schaible and J . Weidlein, Z . anorg. Chem., 1974, 403, 301. G. S. Koptev, N. F. Stepanov, K. N. Semenenko, and B. M. Bulychev, Vestnik Moskou. Uniu., Khim., 1974, 42. M. Hargittai, I. Hargittai, and V. P. Spiridonov, J.C.S. Chem. Comm., 1973, 750. K. Gosling and R. E. Bowen, J.C.S. Dalton, 1974, 1961.
Inorganic Chemistry of the Main -group Elements 164 A determination of the crystal structure of (Me,Tl)' [AlMe,(NCS)]shows that the Al-NCS unit is present, as opposed to the Al-SCN group found in the same anion with the cation NMe;.37q The suggested reason is that there is a significant T1- - - S interaction, which stabilizes the N-bonded form. K(Al,Me6N3) contains a bridging N, There are two forms, however, one being of CZU symmetry (Me groups in the eclipsed conformation) and one of C, (Me groups staggered). U.V. photoelectron spectra have been reported -for a number of adducts of Et,Al and EtzZn.381These show characteristic shifts in bands due to the lone-pair of electrons on the donor. Et,A1 has been confirmed as being a harder acid than Et,Zn. Triethylaluminium reacts with bis-diphenylphosphino-n-propylamineand bis-diphenylphosphino-n-butylamineto give five-co-ordinate (1: 1) adducts of Al.382No reaction occurs with more sterically hindered amines. In these, steric hindrance prevents the P lone-pair from being available to the Al. N.m.r. spectra of the adducts Et,XAl,NH,Bu' (X = C1, Br, or I) may be analysed assuming free rotation about the Al-C and N-C bonds at room temperat~re.,'~Thermal decomposition of these adducts leads to dimers containing the (AlN), ring. When X = Br, (EtBrAlNHBu'), is formed, having three isomers in solution. The most stable isomer can be crystallized out, and shown to have the structure (68).
A series of volatile, tricyclic derivatives (N,C,H,MR,),, where M = A1 or Ga; R = H , D, Me, Et, or C1. results from reactions of pyrazole with the appropriate A1 or Ga A number of physical properties are consistent with the presence of six-membered rings (4N, 2M) in the boat conformation, although inversion processes are rapid even at -90 "C. A C N D 0 / 2 calculation on the (Me2NA1H2),molecule suggests that the structural parameters obtained from electron diffraction are superior to
"' S.
K . Seale and J . L. Atwood, J. Organometallic Chem., 1974, 64, 57. J. L. Atwood and W. R . Newberry, J. Organometallic Chem., 1974, 65, 145. "' G. Levy, P. de Loth. and F. Gallais, Compt. rend., 1974, 278, C, 1405. ''' D . F. Clemens, R. B. Smith jun., and J . G. Dickinson. Canad. J. Chem., 1973, 51, 3187. 3R3 R. E. Bowen and K . Gosling, J.C.S. Dalton, 1974, 964. 3x4 A . Arduini and A. Storr, J.C.S. Dalton, 1974, 503. ""
Elements of Group 111 those from X-ray lar A-! - - -+l interactions. \\
165 Evidence has been found for strong transannu-
II
A 1' Each A1 and N is bound (MeAlNMe), possesses a novel cage to one Me and 3 cage atoms, while each (AlN), unit has approximate C3" symmetry and is well separated from others. The mean Al-N bond length is 1.96 [Cr(NH),][A1(nta),],4H20, where nta is the nitrilotriacetate anion, undergoes a solid-phase reaction to give, finally, Al[Cr(nta),]. It is suggested that the nta'- anion undergoes changes in its co-ordination type during this reaction .387 Stepwise stability constants for complex formation between All" or In''' and 2 -asparaghe or E -glutamine have been evaluated from potentiometric data.38R Al,Cl, reacts with excess PF, to give F,P-AlCl,, for which molecular weight and n.m.r. data support an ethane-like structure with an A1-P bond.," Halogen exchange occurs, to form PCl, + AlF,. Some evidence has been found for reaction in the systems Al,Me6-PF3 and -NH3, but not in Al,Me6-CO, Al,Cl,-CO, BF3-PF3, or A1,C1,-PCl3. Metallation of HPMe, with LiC,H, in diglyme, at -40°C, followed by reaction with A1C13, gives the compound LiA1(PMe2)4.390 This may be used to introduce PMe, groups into Si-X species, by replacement of X.
A.
Compounds containing A1-0, Al-S, or Al-Se Bonds.-The assignment of a band at 503 cm-I to the bending mode of A1,O (D. M. Makowiecki, D. A. Lynch, and K. D. Carlson, J . Phys. Chem., 1971, 75, 1963) has been d i s p ~ t e d . ~A " suggested reassignment of this feature, to the €3," mode of rhombic A1202,has been made. Further work on matrix-isolated i.r. spectra of A1,O has revealed that the bands previously assigned as v1 for this species (ca. 700cm-I) are in fact also due to a dimeric The molecular parameters of M,O (M = Al, Ga, In, or TI), determined by electron diffraction, are listed in Table 4.393A group of Russian workers reported similar data, independently, for Al,0.794 MO calculations, both
"'
M. Pelissier. J.-F. Labarre. L. V. Vilkov, A. V. Golubinsky, and V. S. Mastryukov, J. Chim. phys., 1974, 71, 702. P. B. Hitchcock. G . M. McLaughlin. J . D. Smith, and K . M. Thomas, J.C.S. Chem. Comm., 1973, 934. '" R . Tsuchiya, A. Uehara. and E. Kyuno. Chem. Letters, 1974, 595. ''' R. C . Tewari and M. N. Srivastava, Indian .I.Chem., 1973, 11, 700. 38L) E. R . Alton, R. G. Montemayor, and R . W . Parry, Inorg. Chem., 1974, 13, 2267. 390 G.Fritz and H. Schafer, Z . anorg. Chem.. 1974, 406, 167. 3y1 C.P. Marino a n d D. White, J. Phys. Chem., 1973, 77, 2929. 392 D. A. Lynch jun., M. J. Zehl, a n d K . D. Carlson, J. Phys. Chem., 1974, 78, 236. w3 S. M. Tolmachev and N. G. Rambidi. High Temp. Sci., 1973, 5 , 385. 3v4 S. M. Tolmachev, Yu. S. Ezhov, V. P. Spiridonov, and N. G. Rambidi, J. Struct. Chem., 1973, 14, 854.
Inorganic Chemistry of the Main-group Elements
166
Table 4 Molecular parameters of M,O (M = Al, Ga, In, or T1) Oxide A120 Ga,O
ln,O T1,O
~(M-o)/A 1.72*0.01 1.82 0.0 1 2.00*0.01 2.15*0.01
*
LOMOP 144.5*5 140.5 f 5 144*5 133+5
T/ K 2300-2300 1300 1300 900-1000
CNDO and ab initio, give results which are not consistent with these data.," The homogeneous gas-phase reaction between A1 and 0, proceeds via the rate-determining step: A l + 0, -+ A10+ 0 with a rate coefficient of (3 f2) x lo-" ml molecule-' s-l. This appeared to have no measurable temperature dependence over the range 10001700 K.3y6 Equilibrium measurements in flames give a value for the dissociation energy of A10 of 5.06 f0.08 eV, in agreement with mass-spectrometric results.3y7 Multi-configuration SCF wavefunctions for the ground and some lowIying excited states of A10 reproduce the measured geometrical parameters for this molecule quite well.3y8 1.r. and Raman spectra of KMO,,1.5H2O (M = A1 or Ga) have been interpreted in terms of the presence of [M,0(OH),]2- ions.3yyThese are formed from two MO, tetrahedra sharing one 0 atom. Assignments have been proposed for most of the fundamentals. New oxime derivatives of Al, e.g. Al(OPr'),-,(ONCR'R2),, where R' = H, Me, Et etc., R Z = M e , Et, or Pr", and n = 1-3, result when aluminium tri-isopropoxide reacts with aldoximes and k e t o x i m e ~ . ~ ~ ~ Schiff-bases containing a functional OH group ortho to the azomethine group (CH=N) react with aluminium tri-isopropoxide to give a number of Al-Schiff -base derivatives, Al(OPr'), .,,(SB),,, with n = 1-3.401 'H, I3C, and "A1 FT n.m.r. spectra of tetrameric aluminium isopropoxide are consistent with the structure (69; R = CHMe,).'" One M-C bond in MR, ( M = A l , Ga, In, or T1; R = M e or Et) can be cleaved by SO, in a 1 : l molar reaction.403 The resultant dialkylmetal alkylenesulphonates are dimeric or trimeric in benzene solution, with M atoms bridged by R(O=)SO, groups. The In and T1 compounds are soluble in H 2 0 , dissociating to R,M' and RSO;. E. L. Wagner. Theor. Chirn. Acta. 1974, 32, 295. A. Fontijn, W. Felder, and J . J . Houghton, Chern. Phys. Letters, 1971, 27, 365. "" P. Frank and L. Krauss, Z. Naturforsch.. 1974. 29a, 742. 3y8 G . Das, T . Janis, and A . C. Wahl, J. Chern. Phys., 1974, 61, 1274. 3yy J . Haladjian and J . Roziere, J. Inorg. Nuclear Chern., 1973, 35, 3821. 40n A. Singh, A . K. Rai, and R. C. Mehrotra. Indian J. Chern., 1973, 11, 478. 4U I R . N. Prasad and J. P. Tandon, J. Inorg. Nuclear Chern.. 3974, 36, 1473. J . W. Akitt and R . H. Duncan, J. Magn. Resonance, 1974, 15, 162. '"'H . Olapinski, J . Weidlein. and H . - D . Hausen. J. Organornetak Chern., 1974, 64, 193. -W 3Yh
167
Elements of Group 111 ,.OR
R-AI':-
-OR
A trans -configuration has been tentatively suggested for the complex Al(nap),, where nap = 2-nitroacetophenonato or PhCOCH,NO,. This ligand chelates via the 0 atoms of the CO and NO, group^.'^' Some assignments of i.r. bands have been made. Partial hydrolysis of Me,AlCl,Et,O and Me,AlCl,NCCH,Ph complexes produces derivatives of bis(chloromethyl)alumoxane.405The spectroscopic properties of these suggest the structure (70). Me I
Et 20-
'
A1
c1
M ' e
A series of new dialkylmetal phosphoric and phosphinic acids have been prepared, i.e. of Al, Ga, In, and Tl.'06 Bis(dimethyla1uminium) sulphate has been prepared by the action of Na2S04 on the corresponding chloride or bromide. In solution it is while in the solid phase it is polymeric.'"' monomeric, DZd, Little work has been done on the Group 111 hydrogen sulphates. Vandorpe and Drache, however, have prepared the compounds M(HSOJ, (M = A1 or Ga) by the reactions: M(SO,Cl), + 3H,O
+ M(HSO,),
+ 3HC1
At low H,O pressures the anhydrous compounds are formed; excess H,O produces the hexahydrate~.~'~ 4"4
405
4"6 407
408
R. Astolfi, I . Collamati. and C. Ercolani, J.C.S. Dalton, 1973, 2238. M. Boleslawski, S. Pasynkiewicz, A . Minorska, and W. Hrynibw, J . Organometallic Chem., 1974, 65, 165. B . Schaible, W. Haubold, and J . Weidlein. Z . anorg. Chem., 1974, 403, 289. H. Olapinski and J. Weidlein, Z.Naturforsch., 1974, 29b, 114. B. Vandorpe and M. Drache, Compt. rend., 1973, 277, C , 1121.
168
Inorganic Chemistry of the Main -group Elements The triple sulphates NaMgM"'(S04)3, where M"' = Al, Ga, or In, have been prepared by thermal syntheses, and crystallographic cell parameters reported for all of them.40y "Al n.m.r. spectra of nitromethane solutions of AI(C1O4), together with trimethyl phosphate, dimethyl methylphosphonate, or dimethyl phosphite show that A13+is octahedrally co-ordinated, whereas a tetrahedral species is indicated in the presence of hexamethylpho~phoramide.~~~~ n.m.r. data were also reported for these Aluminium perchlorate and hydroxoperchlorate are both extractable from aqueous solutions by tributyl phosphate-the latter as highly polymerized species.412 If a solution of A1 phosphate is dehydrated to give a mixture with a P,O,/Al,O, ratio of 3:7, and this is then heated to 450-500 "C, a crystalline form of Al(PO,), is This is free from oligophosphate impurities. The arsenates Na,AlH,-,(As04),,yH,0 (0.6 < x < 2; 1< y < 1.5) crystallize in monoclinic lattices (space group C2/rn, C2, or C,) when x is equal to or slightly greater than 1, but in rhombohedra1 lattices when x has any other value.414The diarsenate NaA1As20, crystallizes in the monoclinic system, with the probable space group P2,lc. Molar conductances and i.r. spectral data suggest that the hydrated 6-molybdeno-alurninates and -gallates have the formulae M,[E(HMOO~)~],~H,O."" A more accurate re-determination of the crystal structure of A1,(W04), has been made.416The crystals belong to the (orthorhombic) space group Pbca; the A1 is octahedrally co-ordinated, and the A1-0 distances are between 1.86 and 1.91 A. New diffraction data for gibbsite, a form of Al(OH), with a sheet structure, confirm the 1934 The compound contains double layers of OH- ions, with A13+ ions occupying f of the octahedral sites between the layers. The present publication gives revised interatomic distances as well as the H positions. Potential-pH-temperature relationships in the A1-H20 system have been calculated by a number of methods to assess the problems associated with the corrosion of aluminium.418 R. Perret, R. Masse, J.-P. Peter, and A . Thrierr-Sorel, Cornpt. rend., 1974. 278, C , 95 1 . J.-J. Delpuech, M. R. Khaddar, A. Peguy, and P. Rubini, J.C.S. Chern. Comrn., 1974, 153. D. Canet, J.-J. Delpuech, M . R. Khaddar, and P. Rubini, J. M a p . Resonance, 1974, 15, 325. 4 1 2 1. M. Gavrilova, V. M. Klyuchnikov, L. M. Zaitsev, and I. A . Apraksin. Russ. J . rnorg. Chern.. 1973, 18, 865. 4 1 3 M.I. Kuz'nienkov, V. V. Pechkovskii, and I. 7'. Rurya, Russ. J . Inorg. Chern., 1973, 18, 517. 414 F. D'Yvoire and M. Screpel, Bull. SOC. chim. France, 1974, 121 1 . L. A. Filatenko, B. N. Ivanov-Emin, S. Ol'gin-Kin'ones. B. Zaitsev, V. I. Ivlieva, and A . I . Ezhov, Russ. J . Inorg. Chem., 1973, 18, 419. 4'h J. J . De Roer, Acta Cryst., 1973, B30, 1878. 4 L 7 H. L. Saalfeld and M . Wedde. 2.Krist., 1974, 139, 129. 4 1 x R. T. Lowson. Austral. J. Chem., 1974, 27, 105. 4oy
""
411
Elements of Group I11
169
Aluminium hydrous oxide sols consisting of spherical particles of narrow size distribution are prepared by ageing aluminium salt solutions containing complexing anions (e.g. sulphate) at 98°C for many Once the particles are formed, the sulphate ions are removed by exchange with OHfrom an added base. Solubility products of Al(OH), in aqueous solutions containing N&+, Li', Na', K', or Ca2+ions are (pK,,) 30.55, 33.15, 30.75, 30.36, and 31.00, respectively. The anomalous value for the Li-containing solution was attributed to a specific effect, the nature of which was not 1.r. and broad-line n.m.r. studies of the aluminium-containing species gibbsite, bayerite, and nordstrandite have been made.421The i.r. spectra, in the Al-0 stretching region, could be analysed satisfactorily by the factorgroup approach. For gibbsite, a model having H atoms between sheets of 0 atoms is consistent with the i.r. and n.m.r. data, but similar conclusions could not safely be made for the other compounds. The hydrothermal hydrolysis of Al" in aqueous KC1 solutions may be rationalized in terms of the equations: 2Al" and
+ 2H,O
14A13++34H,O
--i,
[Al,(OH),]"+ + 2H+
+ [Al14(OH)34]8++ 34H'
The [A114(OH)34]8+ species then yields, by an irreversible process, a precipitate of boehmite, y-A100H.422 Standard enthalpies of formation have been calculated for crystalline Cs[Al(NO,),] and Cs2[Al(N03),].423 Raman spectra have been recorded for the liquid systems A1(N03)3,nH20 (n = 20 or 9).'" In each case the spectra are consistent with the presence of [Al(OH,),]" and NO; in the form of solvent-separated ion-pairs. Bands ca. 500 and 300cm-' were assigned to ul(Alg) and u3 or U 4 ( T l g ) A1-0 stretches of [A1(H20)6]3+. The thermal decomposition of A1(N03),,9H,0 proceeds in the following sequence: 136 "C -+ Al2O3,N2O5,4.5Hz0,185 "C + hydrated A1,03.425Similar data were reported for A1,O3,1.5N,O5,8H,O. By i.r. spectroscopy, the NO; ions are not co-ordinated to A13+in any of these compounds. Basic benzoates M(OH)(C,H,O,),,~H,O (M = Al, Ga, or In) have been prepared by potentiometric tit ration^.^'^ Thermal properties and i.r. spectra were studied. A1,03 of high purity is given by the thermal decomposition of the A1 benzoate. 419
R. Brace and E. Matijevik, J. Inorg. Nuclear Chem., 1973, 35, 369 1. Chen, Canad. J. Chem., 1973, 51, 3528. M.-C. Stegmann, D. Vivien, and C. Mazikres, J. Chim.phys., 1974, 71, 761. D.Vivien, M.-C. Stegmann, and C. Mazikres, J. Chim. pltys., 1973, 70, 1502. D. D. Macdonald, P. Butler, and D. Owen, J. Phys. Chem., 1973, 77, 2474. N. V. Krivtsov, G. N. Shirokova, and V. Ya. Rosolovskii, Russ. J. Inorg. Chem., 1973, 18, so3. D. J. Gardiner, R. E. Hester, and E. Mayer, J. Mol. Structure, 1974, 22, 327. B. N. Ivanov-Emin, V. M. Kampos, B. E. Zaitsev, and A. I. Ezhov, Russ. J. Inorg. Chem., 1973, 18, 1564.
"'D. T. Y. 421 422
423 424
425 426
170 Inorganic Chemistry of the Main - group Elements A study of the temperature dependence of volatilization from the faces of leucosapphire, cx-Al,O,, leads to a value of 210 k 2 0 kcal mol-' for the energy of volatilization of this specie^."^' A study has been made of the effect of alkali contamination on Al,O,S i 0 2 catalysts (variable A1,O :SiO, ratio) in the dehydration of isopropyl alcohol and the cracking of ~ u m e n e . ~The ' ~ catalytic effect is markedly decreased by such contamination-the latter reaction being the more susceptible to this. A number of studies of phase relationships in Al-0-containing systems have been made.""'-""' Some soluble aluminosilicates (probably structural units participating in the crystallization of zeolites) have been detected in dilute solutions containing silicate and aluminate anion^.^"' Interaction of Li,CO, and the mineral eucryptite gives a trilithium aluminosilicate, 3Li,0,A1,0,,2Si0,.4"9 The rate of formation of the spinel CuAI,O, (from CuO+A1,0, in a solid-phase reaction at 950-1000 "C) can be explained adequately assuming a three-dimensional diffusion mechani~rn.~'" Cr3' ions may be replaced by A13+in FeCr,O, at 700°C; crystallographic studies confirm that all of the AP' ions are in octahedral ~ i t e s . " ~ ' Solid-phase "A1 n.m.r. spectra have been obtained for epidote, Ca,AI,(Fe,Al)Si,0,,(OH).452 Two different nuclear electric quadrupole tensors 427
V. A . Smirnov. L. V. Povolotskaya. and G . A. Mishchenuk, Russ. J. Inorg. Chem.. 1973. 18, 468.
428
E. M. Akulenok, Yu. K. Danilenko, V. V. Panteleev, E. A. Fedorov, and V. Ya. KhaimovMal'kov, Soviet Phys. Cryst., 1974, 18, 654. H . Bremer, K.-H. Steinberg, and T.-K. Chuong, Z. anorg. C'hem., 1973, 403, 72. 430 M. M. Kazakov, F. L. Glekel', and N. A. Parpiev, Russ. J. Inorg. Chem., 1973, 18, 788. 4 3 ' A . A . Maksimenko and V. G . Shcvchuk, Russ. J. Inorg. Chem., 1973, 18, 741. 4-32 S. I . Berul' and N. I. Griskina, RUSS.J. Inorg. Chem., 1973, 18, 1334. 433 M. Screpel, F. D'Yvoire, and H. Guerin, Bull. Soc. chim. I h n c e , 1974, 1207. 4 3 4 M. 1. Baneeva and N. A. Bendeliani, Doktady Chem.. 1973. 212, 724. 4 3 5 F. Farkas, F. Kovacs, 0. Mug, and M. Gombos, Magyar K i m . Folybirat, 1974. 80, 1. P. Fellner and K. MatiaSovsk9, Chem. Zuesti, 1973, 27, 737. 4 3 7 E. Schultze-Rhonhof, Z. anorg. Chem., 1974, 408, 21. 43H P. Macchioni and H. Saucier, Compt. rend., 1974, 279, B, 99. 439 R . H . Nafziger, High Temp. Sci., 1974, 5, 414. 44" T. N. Nadezhina, V. A . Kuznetsov. E. A. Pohedimskaya, and N . V. Belov, Soviet Phys. Cryst., 1974, 19, 266. 44 I L. M. Bogacheva, Kh. R. Ismatov, and R . Z. Karimov. Russ. J. Inorg. Chem.. 1973. 18, 1642. 142 B. G . Golovkin and A. A. Fotiev, Russ. J. Inorg. Chem., 1973. 18, 1367. 4 4 3 B. M. Nikitin and N . V. Pyatnitsa, Russ. J. Inorg. Chem., 1973, 18, 1028. 4 4 4 M. V. Mokhosoev. S. A . Pavlova. E. I. Get'man, and N. G. Kisel', Russ. J. Inorg. Chem.. 1973. 18, 1123. I "Y. Cudennec and A. Bonnin, J. Inorg. Nuclear Chem., 1974, 36, 273. 446 A . Bon, C. Gleitzer, A . Courtois, and .I.Protas, Compt. rend., 1974, 278, C, 785. "' H. Furuhashi, M. Inagaki, and S. Naka, J. Inorg. Nuclear Chem., 1973, 35, 3707. a 4 x J.-L. Guth. Ph. Caullet, and R. Wey, Bull. Soc. chim. France. IY7.1. 1758. 4 4 y Z. S. Tkacheva a n d L. K. Yakovlev, R i m . J. Inorg. C'hem.. 1073. 18, 358. H. Paulsson a n d E. Koskn, Z. anorg. Chem., 1973, 401, 172. "" F. Chassagneux and A. Rousset, Compt. rend., 1973, 277, C, 1125. 45* T. Tsang and S . Ghose. .J. Chem. Phys.. 1974. 61, 413. 429
Elements of Group I11
171 were observed, corresponding to the All and Al, sites of the epidote structure. The crystal structure of leifite, N~[Si,,Al,(BeOH),0,,],5Hz0, shows that the framework is built up almost exclusively of tetrahedral anions, linked three-dimensionally, except for the Be tetrahedra.453 Diffuse X-ray scattering measurements on a non-stoicheiometric spinel, Mg0,3A1,03, having 10% of octahedral vacancies, lead to the conclusion that the probability of a vacancy occupying a site adjacent to another vacancy (Pw) is 0.20 (cf. 0.10 for a completely disordered The structure of brazilianite, NaA13(P04)2(0H)4, is made up of chains of edge-sharing A1-0 octahedra linked by P-0 tetrahedra, with Na situated in cavities in the The 2p ionization energies of Al in an aluminosilicate containing 6 C.N. aluminium only (kyanite), and in one containing both 4 and 6 C.N. aluminium (e. g. sillimanite) are almost identical.456Thus in such minerals the A1 2p ionization energies cannot be used to diagnose the C.N. of the Al. Reactions of aqueous alkaline media (containing TI', Ba2++ Tl', Ba2' + Li', or Ba2++ Na') with metakaolinite and kaolinite (for Ba2++Li+ only) Non-zeolites included a barium silicate yield a wide variety of hydrate, barium aluminate, aod a number of unidentified "1-containing species. Zeolites of the following types were grown: (i) edingtonite-type (Ba/Li, Ba/Tl) (ii) variants of zeolite L (Ba/Tl, Ba/Li, Ba/Na) (iii) harmotome- or phillipsite-types (Ba/Li, Ba/Na) (iv) gismondite-type (Ba/Na) (v) gmelinite-type (Ba/Na) (vi) yugawaralite-type (Ba/Li) (vii) a lithium-bearing zeolite having no natural counterpart (Ba/Li). The occupancy factor of A1 and Si atoms in a 53% dealuminated Y zeolite, and in the non-dealuminated sample, is ca. 1 in each case.458Thus A1 extraction does not lead to holes in the structure. The synthetic zeolite (Na, Me4N)-V, which is closely related to zeolite N, zeolite 2-21, and zeolite (Na, Me4N) of unknown structure, has been characterized in various ways.459
4s3 454 4s5 456
4s7 458 459
A. Coda, L. Ungaretti, and A. Della Giusta, Acta Cryst., 1974, B30, 396. G. Patrat, M. Brunel, and F. de Bergevin, Acta Cryst., 1974, A30, 47. B. M. Gatehouse and B. K. Miskin, Acta Cryst., 1974, B30, 131 1. P. R. Anderson and W. E. Swartz jun., Inorg. Chem., 1974, 13, 2293.
R. M. Barrer, R. Beaumont, and C. Colella, J.C.S. Dalton, 1974, 934. P. Gallezot, R. Beaumont, and D. Barthorneuf, J. Phys. Chern., 1974, 78, 1550, R. M. Barrer and R. Beaumont, J.C.S. Dalton, 1974. 405.
172 Inorganic Chemistry of the Main - group Elements Several studies have been made of i.r. and crystal struct u r e ~ of~ various ~ ~ - ~ zeolites. ~ ~ (Me,A1)2S is prepared by the reaction of AlMe, with liquid H,S.467It dissolves in benzonitrile with the formation of a 1: 1 complex. The crystal structure of a new high-pressure phase AgAlS2-I1 has been determined.46RIts space group is P3mI (trigonal), and the structure comprises an h.c.p. arrangement of S atoms, with A1 in the octahedral and Ag in the tetrahedral sites. A study of the Al-Al,S, phase diagram reveals the existence of a sub-sulphide, AlS, which seems to be stable only within the temperature range 1010-1060 "C.*"" New cubic high-pressure phases of A1&, Al,Se,, and CuInAi,Se, have been reported; all have spinel-like s t r ~ c t u r e s . ~ ~ ~ ~ ~ ~ ~ Aluminium Halides.-Matrix-isolation techniques have allowed isolation of AlF3, AlF, (AIF),, GaF,, and GaF, which have been examined by i.r. spectroscopy in the range 33-4000 cm-1.472The methods used for generating the species were as follows: (a) Knudsen-cell effusion from GaF,, GaF,+Ga, or GaF,+Al; ( b ) codeposition of Ga or GaF and molecular F, or F atoms. Cryoscopic measurements on the NaF-rich side of the system NaF-AlF3Na20-A1,03 suggest that the chief Al/O-containing species is an A120F:-x complex (containing an Al-0-A1 The only bands seen in the Raman spectrum of the LiF-Li,A1F6 eutectic were assignable to AlF:-; no evidence was found for AlF;, AlF,, or any other species derived from the dissociation of AlF2-.474 Values for the enthalpies of fusion of alkali-metal cryolites may be obtained, using an aneroid, inverse-drop calorimeter with adiabatic shields .475 Some reports of phase relationships in [A1F,I3--containing systems are given in refs. 476-478. 460
L. M. Vishnevskaya. A. A . Kubasoc.. K. S. Tkoang. and K. V. Topchieva, Russ. J. Phys. Chem.. 1973, 47, 873. K.-H. Steinberg, H . Bremer, F. Hofmann, C. M. Minachev. R. V. Dmitriev, and A . N . Detjvic, Z. anorg. Chem., 1974, 404, 129. 142. 462 K.-H. Steinberg, H . Bremer, and F. Hofmann, Z. unorg. Chem., 1974, 407, 162. 463 K.-H. Steinberg, H. Bremer, and F. Hofmann, Z. anorg. Chem., 1974, 407, 173. 464 E. G h i . Cryst. Struct. Comm., 1974. 3, 339. 4h5 P. E. Riley and K. Seff, Inorg. Chem., 1974. 13, 1355. 4hh A. A. Kubasov, K. U . Topchieva, and A . N . Ratov, Russ. J. Phys. Chem.. 1973. 47, 1023. 467 M. Boles,hwski, S. Pasynkiewicz, A. Kunicki. and J . Smola.. .J. Orguncmetalfic Chem.. 1974, 65, I h l . 468 K.-J. Range. G. Engert, and A . Weisx, Z. Nuturforsch., 1974, 29b, 186. 469 T. Farland, J. Gornez, S. K. Ratkje, a n d T. gstvold, Acta Chem. Scand. (A), 1974, 28, 226. 470 K.-J. Range a n d H . 4 . Hubner, Z. Nu!urforsch., 1973, 28b, 353. 47 1 K.-J. Range and H.-J. Hubncr, Z. Naturforsch., 1973. 28b, 3 5 5 . J72 J . W . Hastie, R. H. Hauge. and J . I-. Margrave, J . Fluorine Chem., 1973, 3, 285. 4 7 3 T. Fprland and S. K. Ratkje, Acta Chem. Scand., 1973, 27, 1883. 4 7 4 S . K. Ratkje and E. Rytter, J . Phys. Chem.. 1974, 78, 1499. "' B. J. Holm and F. Granwold. Acta Chem. Scand., 1Y73, 27, 2043.
173 Elements of Group I11 The enthalpy of mixing of molten NaF and AIF, may be measured directly by isothermal calorimetry at 1284 K, in the composition range 0-25'/0 AlF,, and by drop calorimetry in the range 25--50% A1F3.479 There is no evidence, again, for any anion other than AlF;-, although there is some dissociation to AlF, and F-. Solutions of hexafluoroaluminic acid can be prepared by dissolving ALO, in aqueous HF."" On addition of the appropriate cation, salts of the AlF$ ion are precipitated. Concentrated solutions of the acid are only stable for short times, and give P-MF,,3Hzo on standing. 1.r. and Raman spectra of K3MF, (M=Al, Ga, In, or TI) have been obtained and v l ,v3, v4, and v 5 assigned for each of the octahedral anions.481 A refinement of the structure of prosopite, an aluminofluoride mineral, CaAl,F,(OH),, has been reported.4*' X-Ray data were also given for tikhonenkovite, Sr,[Al,F,( OH),],2 H,O .483 KAlOCl, has a structure derived from cubic close packing of C1 atoms, with all the octahedral sites populated statistically by the cations, (K+ A,).'" The tetrahedral sites are half-populated by oxygens. The Li+ and Na' salts are isostructural, but contain vacancies. A study of 13C n.m.r. spectra of solutions of AlCl, in EtOH, in the presence of C10; ions, has established that the anions participate in co-ordination to the A13+ion, in addition to the solvent. Contact ion-pairs or triplets, such as A1Cl2+,AlCld, and A1(C104)2+,were suggested as the most likely species.485 Photoelectron spectroscopy in the range 50--250°C has been used to study the equilibria: 2MX3 MZX6 (M = Al or Ga; X = Cl,,Br, or I). The p.e. spectra of the monomers are all very similar to those of BX,, while the dimer within any series is favoured by the lightest M or X.4x6 1.r. spectra of monomeric MX, (M= Al, Ga, or In; X = C1, Br, or I) have ~ 'and v4 were found to have been measured in the range 30-700 ~ r n - ' . ~v2 very similar values in each case. Highly reactive A1 powder is prepared by reducing anhydrous aluminium halides in organic solvents (e.g. THF) under an inert "' S. A. Mikhaiel, Acly Chem. Srand, 1973, 27, 397Y. 477
J. Vrbenskri, I. KoStenskit, and M. Malinovsk?, Chem. Zuesti, 1973, 27, 577. Fellner, Coll. Czech. Chem. Comm., 1973, 38, 3014. 47y J . L. Holm, High Temp. Sci., 1974, 6, 16. '"' V . kepanovit, S. RadosaljeviC, and J . MiSoviC. J. Fluorine Chern., 1973, 3, 403. 'I M . J . Reisfeld, Spectrochim. Acta., 1973, 29A, 1923. Z. V . Pudovkina, N. M. Chernitsova, and Yu. A. Pyatenko, J. Struct. Chem.. 1973, 14, 345. 4x 7 Z. V . Pudovkina, N. M. Chernitsova, and Yu. A. Pyatenko, J. Struct. Chem., 1973, 14, 445. 4x4 V . G. Kuznetsov, S. I. Maksimova, and A. I.. Morozov, J. Struct. Chem., 1973, 14, 441. 4 x 5 J . S. Martin and G. W. Stockton, J . M a p . Resonance. 1973, 12, 218. 4R6 M. F. Lappert. J. B. Pedley, C. J . Sharp, and N . P. C . Westwood, J. Electron Spectroscopy, 1974, 3, 237. 4H7 G. K. Selivanov and A. A. Mal'tsev, J . Struct. Chem., 1.973, 14, 889. "' R . D. Rieke and L.-C. Chao, Synth. React. Inorg. Metal-org, Chem., 1974, 4, 101.
"' P.
174
Inorgqnic Chemistry of the Main-group Elements The ClAlCl bond angle in AlCl,-NH, is l16.9*0.4°.4s9 This contradicts an earlier value for the angle in AlCl, itself of ca. 112" (M. L. Lesiecki and J. S. Stirk, J . Chem. Phy., 1972, 56, 4171). A tensimetric analysis of the vapours above MAlCl, (M = alkali metal) shows that they contain AlCI, and MAlCl,.""' The partial pressure of the former decreases along the series from Li to Cs. E.m.f. measurements using the cell: Al(s)~AICl,-MC1(~)(C12 (graphite) yield (M=Na, K, Rb, or Cs), in the temperature range 200-600°C, thermodynamic data which, in the concentration range around 50 mol% of A1C13, may be interpreted in terms of the eq~ilibria:~" Al,Cl, A1,Cl;
+ Ci- * A1,Cl;
+ C1- * 2AlC1;
At 600K, Al,Cl,(g) reacts with CrC1, to give a gaseous complex CrAl,Cl,.""' The electronic spectrum of this leads to the suggestion that the Cr has distorted octahedral co-ordination (by Cl's). Pd(AlCl,), may be prepared by an analogous reaction.493 The X-ray powder diffraction pattern could not be indexed unambiguously, while a small paramagnetic susceptibility was found, indicative of distortion from square-planar geometry. "Cl n.q.r. spectra have been reported for the chloroaluminate groups in Te,(AlC1,)2, Bi5(AlC14)3,e t ~ . , ' Those ~ with ionic AlCl; units give chlorine transitions in the range 10.6-11.3 MHz, while those in which the AlCl; groups are more strongly co-ordinated, or form Al,Cl;, give such transitions at higher frequencies. A number of new complex Al-containing halides have been detected mass-spectrometrically, e. g. CuAlCl, and CU,A~,C~,."~' Phase-relationships in the systems A1C1,-MgC1,-Et20496 and 6Na, 3Ba,2A1, 6C1497have been elucidated. There is some evidence for the interaction of alkynes with AlBr, at low temperature^.^^' Thus, pent-2-yne, hex-2-yne, and hex-3-yne all give i.r. bands ca. 2200 cm-' assigned to (alkyne)AlBr, complexes. 4xy 4y"
")' 4y2 4Y1
494
495 496
"' "'
I. Hal-gittai and M. Hargittai, J . Chem. Phys.. 1971. 60, 1563. A. I . Morozov and I. S. Morozov, Russ. J. Enorg. Chem., 1973, 18, 520. H . Ikeuchi and C. Krohn. Acta Chem. Scand., 1974, 28A, 38. M. Aits and H. Schafer, Z . anorg. Chem., 1974. 408, 37. G . N. Papatheodorou, Inorg. Nuclear Chem. Letters. 1974, 10, 115. D. J. Merryman. P. A. Edwards, J . D. Corbett, and R. E. McCarley, Inorg. Chem., 1974, 13, 1471. M. Binnewies and H . Schafer, Z . anorg. Chem., 1974, 407, 327. K. M. Sernenenko, E. A. Lavut, and A. P. Isaeva, Russ. J. Inorg. Chem., 1973, 18, 433. M. A. Kuvakin, L. I. Talanova, and A. I. Kulikova, Russ. J. Inorg. Chem., 1973, 18, 602. H. H. Perkampus and W . Weiss. Z . Naturforsch.. 1974, 29b, 61.
Elements of Group I11
175
TeC14 forms stable, highly polar, 1:1 complexes with A1Br3, GaCl,, and GaBr3.499 Hydrolysis of NaAlBr, proceeds by different mechanisms, depending on the temperature.500The first stage in the low-temperature mechanism is the formation of a hexahydrate, which has been characterized by X-ray powder diffraction. 3 Gallium General.-Gallium complexes of rn -cresolphthalexon S (a compIexone derived from the triphenylmethane fragment, containing 0 and N donor atoms) have some potential for the photometric determination of Ga.501 Ga forms a mixed-ligand complex with quercetin and antipyrine in the presence of strong acids; the complex is extracted quantitatively into CHC1,.502 A rapid and simple separation method for G a and Zn involves extraction of GaI'I from aqueous acidic solutions by l-phenyl-2-methyl-3-hydroxy-4pyridone.
Gallium Hydrides.-CsGaH, forms two solvates with diglyme: CsGaH4,4DG and CsGaH4,2DG.'04 The N-methyldiethanolaminogallane dimer, [MeN(CH,CHzO)2GaH]z, contains 5 C.N. gallium-the dimerization occurring via a four-membered Ga,O, ring (71)."' The molecule has C, symmetry within experimental error.
Dideuterio(pyrazo1- 1-y1)gallane dimer has the structure shown in Figure 24.506 The six-membered ring, Ga(NN),Ga, is in the boat conformation. I. P. Gol'dshtein, E. N. Gurjianova, M. E. Peisakhova, and R. R. Shifrina, J . Gen. Chem. (U.S.S.R.),1973, 14, 2332. B. Dubois and R. Vandorpe, Compt. rend., 1973, 277, C, 1133. A. I . Busev and A. A. Cherkesov, Russ. J. Inorg. Chem., 1973, 18, 630. 502 N. L. Olenovich and L. I . Kovalchuk. Zhur. analit. Khim., 1973. 28, 2162. B. Tamhina, M. J . Herak, and K. Jakopi-it, J . Less-Common Metals, 1973, 33, 289. T. N. Dyrnova and Yu. M. Dergachev, Doklady Chem., 1973, 211, 614. '"'S. J . Rettig, A. Storr, and J. Trotter, Canad. J . Chern., 1974, 52, 2206. D. F. Rendle, A. Storr, and J. Trotter, J.C.S. Dalton, 1973, 2252.
4yy
Inorganic Chemistry of the Main- group Elements
176
Figure 24 Molecular structure of the dideuterio(pyrazo1-1 -yl)gallane dirner (Reproduced from J.C.S. Dalton, 1973, 2252) Compounds containing Ga-C Bonds.-The reaction of Ga(g) and PN(g) in the presence of solid graphite produces gallium monocyanide (detected mass-spectrometricall y) :‘07 C(s) + Ga(g) + PN(g) F iP, + GaCN(g) K+[Me2Ga(CN)2]-is prepared by the reaction : K,[Hg(CN),]
+ 2GaMe, + 2K[GaMe,(CN),] + HgMe,
An i.r. spectrum of the product, with some assignments, has been given.5o8 An electron-diffraction study of GaMe, gave the following structural pararneter~:’~~ r(GaC) 1.967 f0.002, r(CH) 1.082 f0.003 A, LGaCH 112.1*0.8”, and LCGaC 118.6”. The methyl groups are freely rotating at room temperature. Some thermochemical parameters have been listed for Ga trialkyls.“’ The trialkylgallium-halogeno complexes (R,GaX)- (R = Me or Et, X = F; or R = M e , X = B r ) and [(R,Ga),X]- (R and X as before) have been prepared, ‘and their vibrational spectra reported.’ll Compounds containing Ga-N, Ga-P, or Ga-As Bonds.-GaGaN contains layers of Ga atoms strongly bound to N atoms (Ga-N distance= 1.863 A), with Ca atoms placed between these layers (each co-ordinated to five N’S).”~ Raman spectra of a single crystal and i.r. spectra of polycrystalline NaGa(NH,), may be assigned in terms of Td symmetry for the [Ga(NH2)4]p ion at room temperature, and S, symmetry at 2 0 K.”3 5(IR
so9 51”
’12 ’13
M. Guido and G. Gigli, J . Chem. Phys., 1974, 60, 721. T. Ehemann and K. Dehnicke, J. Organometallic Chem.. 1974, 64, C33. B. Beagley, D. G. Schmidling, and I. A. Steer, J. Mol. Structure, 1973, 21, 437. G . M . Kol’yakova, 1. B. Rabinovich, and E. N. Zorina, Doklady Chem., 1973, 209, 245. 1. L. Wilson and K. Dehnicke, J. Organometallic Chem., 1974, 67, 229. P. Verdier. P. L’Haridon, M. Maunaye, and R. Marchand, Acta Cryst., 1974, B30, 226. G. Lucazeau, A. Novak, P. Molinie, and J. Rouxel. J. Mol. Structure. 1974, 20, 303.
Elements of Group III
177
1.r. data for the compounds (Me4N),[Ga(NCO),] and Ga(NC0),,3L (L= bipy or phen) indicate that the [Ga(NC0)J3- anion contains cyanate groups bonded via the 0 atom.514In agreement with this, the ionic species is unstable, decomposing in air. The other compounds contain Ga-NCO units. The standard enthalpy and entropy of formation of GaP were derived from composition and vapour-pressure measurements along the Ga-rich liquidus of the Ga-P Variable-temperature n.m.r. measurements on GaMe,-AsEt, and GaClMe,-AsEt, systems yield estimates for the free energy of formation of the adducts: Me,Ga,AsEt, 7.3 f 1.5, ClMe,Ga,AsEt, 9.7+ 1.5 kcal m 0 1 - l . ~ ~ ~ Compounds containing Ga-0 or Ga-S Bonds.-When the vapour above G a z 0 3or In,O, is condensed in low-temperature matrices, the oxides M,O and M40, (M = Ga or In) are produced, and identified by i.r. spectroscopy.517Passing 0, over In-Ga alloys yields InOGa and Ga,In,-,O,. A study of the kinetics of the extraction of Ga” from 0.1 moll-’ aqueous C10; solutions into CHCl, using thenoyltrifluoroacetone (HA), and of the back-extraction of the tris-chelate GaA,, shows that the rate-determining step in the former process involves association of the species GaOH” with A- in the aqueous The back-reaction is thought to be the exact reverse. The competing ligand system alizarin-3-sulphonic acid-OH- has been used to determine formation constants of mononuclear hydroxo-complexes of Ga at 25 “C, and the hydrolysis constants of gallium ions at I = 0.1-1 .O.”’ The methanolysis of Ga” and In” cations in anhydrous methanol produces the complex cations [Ga, (OMe),lZ’ and [Ga,,,~(OMe)p]”m’-p’, where rn’ > rn, or for In, [In,(OMe)p]‘3m-p’species appear simultaneously with monomeric [In(OMe)T’ and [In(OMe)2]+.520 Bis(dimethylgal1ium)oxalatecontains a Ga,C20, unit that is built up from two fused five-membered rings (72).521
514
515
‘Ib
‘I7 518 519
’’O
521
A. Yu. Tsivadze, G. V. Tsintsadze, and Ts. L. Maknatadze, J. Gen. Chem. (U.S.S.R.), 1974, 44, 157.
M. Ilegems. M. B. Panish, and J. R. Arthur, J . Chem. Thermodynamics, 1974, 6, 157. B. G. Gribov, G. M. Gusakov, B. I . Kozyrkin, and E. N. Zorina, Doklady Chem., 1973, 210, 515. A. J . Hinchcliffe and J . S. Ogden, J . Phys. Chem., 1973, 77, 2537. T. Sekine, Y. Komatsu, and J.-1. Yumikura, J . Inorg. Nuclear Chem., 1973, 35, 3891. E. A . Biryuk and V . A. Nazarenko, Russ. J. Inorg. Chem., 1973, 18, 1576. L. Asso, J. Haladjian, P. Bianco, and R. Pilard, J . Less-Common Metals, 1974, 35, 107. H.-D. Hausen, K. Mertz, and J. Weidlein, J. Organometaflic Chem., 1974, 67, 7.
178
Inorganic Chemistry of the Main -group Elements
The new compounds 2GaONO3,N,O, and Cs[Ga(NO,),] have been prepared, while the species NO[In(NO,),] and Cs[In(NO,),] were synthesized by a new method.s22 The first stage in the thermolysis of Ga(SO,Cl), is dissociation into GaCI, + SO,, at 70 “C and atmospheric pressure.523The second stage involves reaction between these to give Ga,(SO,), + SO,Cl,. The GaO, octahedron in tris(acetylacetonato)gallium(m) is very close to being completely regular.524The average Ga-0 bond length is 1.952(8) A, with an average ligand ‘bite’ of 2.802A. Reactions of gallium isopropoxide with monofunctional bidentate Schiff bases, o-HOC6H4CMe=NR and 2-HOCloH&H=NR (R = Et, Pr”, or Ph), yield complexes Ga(OPr’),SB, Ca(OPr’)(SB),, and Ga(SB)352’The Ga is thought to be respectively four-, five-, and six-co-ordinate in the three classes of complex. E.s.r. parameters have been reported for the adducts Ca,Cl,-tempo and GaC1,-tempo, where tempo is 2,2,6,6-tetramethylpiperidine nitroxide.s26 Adducts of Ga and I n perchlorates with tetramethylene sulphoxide, M(C104),,6TMS0, and of Ga perchlorate with thioxan oxide, Ga(C104),,6TS0, have been prepared and ~haracterized.~’~ A considerable shift of v(S=O) to lower wavenumber indicated co-ordination via the sulphoxide oxygen. The ternary oxides CrMnGaO,, NiMnGaO,, CuMnGaO,, and ZnMnGaO, crystallize with the cubic spinel structure.”* The structure of monoclinic CaGaO, is built up from 6 G a 0 , tetrahedra, with r(Ga0) = 1.81-1.87 A.s29 Gallium metatitanate, GazTiOs, can be obtained by heating the gallium peroxotitanate [Ga(OH),], [0,Ti(OH)20],3H20,but the product is metastable, and further heating at 1000 “C leads to decomposition to Ga,O, and a gallium titanate richer in Ti.53” NaGa,,O,,(OH),, prepared by hydrothermal techniques, is monoclinic, space group P21/m.531 Both GaO, octahedra and GaO, tetrahedra are present in the structure, with mean values for r(GaO),,, and r(GaO),,, of 2.00 and 1.85 A, respectively. The phase diagram of the system MnS-Ga,S, has been determined, and 7 intermediate phases have been characteri~ed.’~~ ’” ”’ 524
’” 52h 527
528 “’)
”’ ’’’ ”()
B. V. Ivanov-Emiii. Z. K. Odinct\. V. .A. HcIonoso\. and B . E . Zaitsec. R[c,\.\. ./, I t t o r g . Cheni.. 1Y73, 18, 6 2 3 . M. Drache. B. Vandorpe. and J. Heubel. Rev. Chim. rninkrale, 1973, 10, 505. K. Dymock a n d G. J . Palcnih. A c t u Crysf.. 1974. €530, 1361. R. N . Prasad and J. P. Tandon, J. Less-Common Metals. 1974, 37, 141. C . Hambly and J . B. Raynur. J.C.S. Dultoti. 1Y71. 603. C . Vicentini and W. N. De Lima. Anuis Acud. Drasil. Cienc.. 1973, 45, 719. P. D. Bhalerao, D. K. Kulkarni. and V. Ci. Kher, Prarniina, 1973, 1, 230. H. J . Deiseroth and H. Muller-Buschhaum. Z . unorg. Chem.. 1973, 402, 201. E. Perte and M. StrBjcscu. Rev. Roumaine Chirn., 1974, 19, 395. A . N. Christensen. Acta Chem. Scand., 1974, 28A, 145. M.-P. Pardo, M. Julien-Pouzol. S. Jaulmes. and J . Flahaut, Cornpt. rend., 1973, 277, C. 1021.
Elements of Group 111
179
Gallium Halides.-NH,GaF,-NH,AlF4 and y -GaF,-y -AlF, both form continuous series of solid solutions, with linear relationships between composition and lattice constants.533 The He (I) p.e. spectra of MX, ( M = G a or In, X=C1, Br, or I) have been reported and assigned.534A comparison of these results with those for BX, suggests a revision in the assignment of the outermost e’ and e” peaks for BBr, and BI,. Ga13 and InI, exhibit splitting of the band due to ionization from an e” MO (D3,,symmetry), which suggests that either the of the ion is pyramidal. neutral ground state or the first excited state (’E”) The vibrational spectra of GaX,,H20 (X = C1 or Br) can be assigned in and H,O (C2u)rather than the terms of the ‘local symmetry’ of GaX,O (GU) overall symmetry of the adducts (Cs).535 Four ‘H n.m.r. signals are seen for solutions of GaCl, in a ~ e t o n i t r i l e . ~ ~ ~ The most intense is associated with the bulk solvent, and shows two satellites arising from 13Ccoupling. The fourth varies in area with change in Gar’’ concentration and that of total chloride (LiCl added). Co-ordination numbers of the MeCN can be calculated and show that there is substantial displacement of the MeCN from the co-ordination sphere by added LiCl. Two ’lGa signals are seen, the low-field signal being the more intense and at a similar position to that of GaCl;. The high-field signal is associated with [Ga(MeCN)J3’. Co-ordination numbers can be calculated and are in good agreement with those from the ‘H data. All the results can be rationalized on the basis of: (n + 2)Ga,Cl,
+ 6MeCN + [Ga(MeCN)J3++ 3GaC1; + nGa,C16
An improved synthesis of Bu”,GaCl,-, (n = 1-3) has been rep~rted.’~’ This is a simple metathetical reaction, in a hydrocarbon solvent: GaCl, + nLiBu” + Bu”,GaCl,-,
+ nLiCl
Vibrational assignments have been made for NO’GaCl;, prepared by the reaction of NOCl+ GaC1, in a variety of solvents, or by dissolving G a metal in NOCl.”8 A comparison of the spectra of crystalline NO’GaCli with that of the A1 analogue shows that they are closely related structurally. Series of mixed-halide complexes of Ga”, i.e. Ga,X,Y,-,, where X = C1, Y = Br or I; X = Br, Y = I; n = 1-5, are present in mixtures of G a 2 x - and Y- in MeN02 Individual members cannot be isolated, but vibrational spectroscopic data could be obtained by examining solutions 533
524
’” s3h 537 538
s39
W . Stoeger. A. Rabenau, and H. M. Haendler, Z . anorg. Chem., 1974, 408, 92. J . L. Dehmer. J . Berkowitz, L. C. Cusachs, and H. S . Aldrich, J. Chem. Phys., 1974, 61, 594. J . Roziere, M.-T. Roziere-Bories, A. Manteghetti, and A. Potier, Canad. J. Chem., 1974, 52,
3273. S. F. Lincoln, Austral. J. Chem., 1972, 25, 2705. R. A. Kovar, G. Loaris, H. Derr, and J . 0. Callaway, Inorg. Chem., 1974, 13, 1476. P. Barbier, G. Mairesse, F. Wallart, and J.-P. Wignacourt, Compt. rend., 1973, 277, C, 841. K. H. Tan and M. J. Taylor, Inorg. Nuclear Chem. Letters, 1974, 10, 267:
180
Inorganic Chemistry of the Main - group Elements
over a wide range of X/Y ratios. It was possible to assign v(Ga-Ga) in all 15 of these compounds. The Ga complex chlorobis(8-hydroxy-2-methylquinolinato)gallium(111) contains five-co-ordinate Ga (trigonal bipyramidal), with r(GaC1) = 2.190(2) A, r(GaN) = 2.108(5) and 2.104(5) If appropriate amounts of GaBr, and Ga are melted together at 180 "C for The Raman spectrum of 48 h, a species GaBr,., is deposited on this showed bands characteristic of Ga,Br;-, and so it was formulated as Gaz+Ga,Bri-, i.e. Ga4Br6. The presence of a Ga-Ga bond in Ga:'BrE- has been confirmed by an X-ray diffraction study of (Pf,N)2Ga2Br6.542 The Ga-Ga bond length is 2.419A7 and the anion possesses D,, symmetry (73). Br
\114.1" n
2.37wBr
Other Gallium Compounds.-Thermodynamic parameters for GaSb and GaSb, have been obtained from high-temperature mass-spectrometric measurernent~.~~, X-Ray and other studies on the solid solutions Gal-,Ge,Cr,N have elucidated the various structural changes which occur with temperature.'"" M06Ga1, is monoclinic, and belongs to a new structure type.545The chief structural units are MoGa,, polyhedra arranged at the corners of distorted cubes, and Ga layers. There are no Mo-Mo contacts, no Ga-Ga pairs, but some very short Mo-Ga distances. Cluster compounds Mn,(CO)& -MMn(CO),], have been prepared and
"')
541 542
s43 s44
54s
K. Dymock and G. J. Palenik, J.C.S. Chern. Comm.. 1973. 884. M. Williamson and 1. J . Worrall, Inorg. Nuclear Chern. Letters, 1974, 10, 747. H. J . Cumming, D. Hall, and C. E. Wright, Cryst. Struct. Cornrn., 1974, 3, 107 V. Piacente and G. Balducci, High Temp. Sci., 1974, 6, 254. N . Nardin, G. Lorthioir, and R . Fruchart, Bull. SOC.chirn. France. 1973, 2959. K. Yvon, Acta Cryst., 1974, B30, 853.
Elements of Group III
181
studied by X-ray diffraction (M = Ga or In).546.547 They are isomorphous and contain a planar M,Mn4 unit (74), in which there is a Mn-Mn bond. Another Ga-containing cluster compound is produced by the reaction: 3Na[Co(CO),] + GaBr,
i ,
GaCo,(CO),,
+ 3NaBr
1.r. and mass spectral data are consistent with the structure (75).548 X-Ray diffraction studies show that all members of the CuGal-,Fe,Sz When x = series ( 0 s x s 1.0) crystallize with the chalcopyrite 0.025 the magnetic moment for Fe approaches the spin-only value (5.92 B.M.). 4 Indium
General.-The half-life of the isotope ”lgIn has been measured as 30.0 h0.2 s-in agreement with, but more precise than, earlier values.5so A highly reactive indium powder is produced by the alkali-metal reduction of indium salts (e.g. InCl,) in hydrocarbon An extractio-photometric method for the determination of indium in Zn ores involves the formation of mixed complexes of In with antipyrine and q~ercetin.~~~ Indium may be estimated by photometric methods as the malachite green tetrachloroindate; this may be extracted from aqueous acid by benzene, CCL, etc.553 Compounds containing Bonds between In and Group VI Atoms.Evaluation of apparent molar volumes leads to the identification of the [h(&o)6]3+ cation in aqueous solutions of non-complexing mineral In aqueous HCl or HBr, mixed halogeno-aquo complex cations are produced, i.e. [In(H20),C1]*+etc. Dimethylindium carboxylates are formed from Me,In,OEt, + acid in Et,O.”’ 1.r. spectra of these compounds show that the carboxylate groups are biden tate. 1.r. spectra of the vapour over indium and thallium metaborates can be assigned to monomeric species MB02, which have a cyclic structure (76).’”
(76) H. Preut and H.-J. Haupt. Chem. Ber., 1974, 107, 2860. s47 H.-J. Haupt and F. Neumann, J. Organomrtnllic Chem., 1974, 74, 185. 548 W. Kalbfus, J. Kiefer, and K. E. Schwarzhans, Z. Naturforsch., 1973, 28b, 503. 549 M . DiGiuseppe, J. Steger, A. Wold, and E. K o s h e r , Inorg. Chem., 1974, 13, 1828. ”O 0. Scheidemann and E. Hageba, Inorg. Nuclear Chem. Letters, 1974, 10, 47. ’” L.-C. Chao and R. D. Rieke, J . Organometallic Chem., 1974, 67, C64. ’” N. L. Olenovich, L. I. Kovalchuk, and E. P. Lozitskaya, Zhur. analit. Khim., 1974, 29, 47. 553 P. P. Kish and I. I. Pogoida, Zhur. analit. Khim., 1974, 29, 52. s54 J. Celeda and D . G. Tuck, J . Inorg. Nuclear Chem., 1974, 36, 373. 5 5 5 W. Lindel and F. Huber, Z. Naturforsch., 1973, 28b, 517. ss6 A. M. Shapovalov, V. F. Shevel’kov, and A. A. Mal’tsev, J. Struct. Chem., 1973, 14, 514. 54h
182 Inorganic Chemistry of the Main -group Elements The indium and thallium sulphates M:M"'(SO,), (MI = Na, K, Rb, or Cs) have been prepared; they belong to the same rhombohedra1 crystal structures as the analogous A1 A study of the (NH4),S04-In,(SO,), system confirmed the existence of the anhydrous alum NH,In(SO,),, together with the sulphate (NH4)31n(S04)3, which exists in two (a and p ) forms. The high-temperature ( p ) form is rh~mbohedral.~'" (NH,),[I~(HMOO,)~(MOO~)],~H~~ has been isolated from a mixture of NH, paramolybdate and In(N0,)3 ~ 0 1 u t i o n s It .~~ is~thought that the In is octahedrally co-ordinated, with bidentate MOO, and unidentate HMoO, (77). OH
(77)
The reaction of InCl, with Cs6P3Ol0in aqueous solution leads to a number of phases of variable composition (indium basic and mixed tripolyphosphates) and also an indium tripolyphosphate with the composition Cs21nP,0,,,8H,0.5"o The In' halides react with refluxing acetylacetone ( = Hacac) to give a mixture of In(acac), and Ir~X,(acac).~"' The latter could not be isolated in pure form, but some crystalline derivatives could be produced by reaction with N-donors, e.g. [InX,(acac)(L-L)],EtOH (L-L = 2,2'-bipyridyl or 1 , l O phenanthroline) or [InX,(acac)L,],EtOH (L = py or ['H,]py). These are all apparently six-co-ordinate, with InO,X,N, units, but no decision could be arrived at concerning the symmetry of these. Indium(1ir) carboxylates In(RCOO), (R = H, Me, Et, P f , Pr', or But) have been prepared from metallic In or InMe, and the anhydrous carboxylic acid. The i.r. spectra show that the carboxylate groups could be either chelating or bridging, but no definite conclusion concerning the structure or the C.N. of the In could be reached.562 Stability constants have been determined for the species [In(C4O,H,),l3and [In(C406H3),]"-obtained by interaction of In3' with tartaric Solvent extraction of indium(rI1) thiocyanate, In(SCN),, with tributyl phosphate in hexane is markedly enhanced by the presence of background NaC104: it was concluded that this is due chiefly to a salting-out effect.564 517
R. Perret, J . Tudo, and B. Jolibois, J. Less-Common Metals, 1974, 37, 9. Tudo, M. Tudo, and R. Perret, Compf. rend., 1974, 278, C, 117. B. N . Ivanov-Emin, L. A. Filatenko, B. E. Zaitsev, and A . 1. Ezhov. Russ. J. Inorg. Chern., 1973, 18, 512. G. V. Rodicheva, E. N . Deichman, I. V. Tananaev, and Zh. K . Shaidarbckova, Russ. J. Inorg. Chern., 1973, 18, 1352. J . G. Contreras and D. G. Tuck, J.C.S. Dalton, 1974, 1249. W. Lindel and F. Huber, Z . anorg. Chem., 1974, 408, 167. G. Marcu, M. Suciu, and A . V. Botar, Rev. Roumaine Chim., 1974, 19, 577. Y . Hasegawa a n d T. Sekine, J. Inorg. Nuclear Chern., 1974, 36, 421.
"' J. '"' 5hL 563
564
Elements of Group 111 183 Some information on the structure of amorphous InSe and InTe films has been obtained by electron-diffraction Indium Halides.-Compositions of halogeno- and thiocyanato-complexes of In in DMSO have been determined potentiometrically at 25 "C, and stability constants have been calculated.566 The Raman spectra of molten InC1,-KCl mixtures (50-100 mole% InC1,) may be analysed in terms of the species InCl;, In2C1;, and In2C&.567 These are thought to have similar structures to the A1 and Ga analogues. Raman spectra of the indium bromides InBr,, InBr,, In,Br,, In,Br,, In,Br,, and InBr have been obtained in the solid phase. For In4Br7,InsBr7, and In7Br9 these were consistent with the formulations: 51r1+(InBr;),(InBr,)~-, 31n+(InzBr6)'-Br-, and 61n+(InBr,)3-3Br-, respect i ~ e l y . ' The ~ ~ phase In,Br, could not be confirmed; InI, gave a spectrum consistent with In+(InIJ . "'In and halogen n.q.r. spectra of several dimethylindium compounds show that Me,InBr and Me21nI have the Me,TlBr-type of structure (linear MeJn equatorially surrounded by a square-planar arrangement of halogens).569MeJnCl is distorted from this, while the MeJnF has a nonlinear MeJn group. 'MeInI,' has been confirmed as [Me,In][InI,], and MeInBr, and EtInI, are halogen-bridged dimers. The small asymmetry parameter found in the n.q.r. spectrum of MeInI, is evidence for the presence of MeJn' and InIf- ions (or possibly a polymeric unit containing axially symmetric In atoms), and not an unsymmetrical dimer.570 Phase diagrams of the systems TlI-InIS7' and M12-In12, where M=Cd, Zn, Sn", Pb", Co", or Mn1',572have been reported.
Other Indium Compounds.-The adducts CpIn,BX, (X = F, C1, Br, or I) have been prepared by the simple reaction between CpIn and BX,.573Their vibrational spectra are consistent with the presence of monomers (78).
mH
In-B-X/x
"' Yu. G. Poltavtsev, V. P. Zhakarov, and T. V. Remizovich, Soviet Phys. Cryst., 1974,18,701. V. M. Samoilenko and V. I. Lyashenko, Russ. J . lnorg. Chem., 1973, 18, 1578. H. A. @ye, E. Rytter, and P. Klaeboe, J . Inorg. Nuclear Chem., 1974, 36, 1925. 5'R J. E. D . Davies, L. G. Waterworth, and I . J. Worrall, J . Inorg. Nuclear Chem., 1974, 36, 805. "') D . B. Patterson and A. Carnevale, Inorg. Chem., 1974, 13, 1479. 570 W. A. Welsh and T . B. Brill, J . Organometallic Chem., 1974, 71, 23. 5 7 1 0. N. Postnikova, Yu. N. Denisov, P. I. Fedorov, N. S. Malova, and L. A. Radushkevich, Russ. J. Inorg. Chern., 1973, 18, 762. "* Yu. N. Denisov, N. S. Malova, and P. I . Fedorov, Russ. J. Inorg. Chem., 1973, 18, 722. 573 J. G. Contreras and D. G. Tuck, Inorg. Chem.. 1973, 12, 2596. 566
567
Inorganic Chemistry of the Main -group Elements
184
In,Te, is isomorphous with In,Se,."" The structure is built up of two centrosymmetrically related interlocking continuous sheets of atoms running perpendicular to a. These are constructed of interlinked fivemembered InTe rings forming chains parallel to c, which are cross-linked by strongly bound In-In-In units, forming, in ionic terms, the homonuclear triatomic species (In$+. C O h 3 is made from the elements at 4OO0C, and is stoicheiometric. It crystallizes in the tetragonal system, and the structure is based on layers of square-triangular nets, related to CoGa, and Si2U,.57s Lattice constants have been reported for the hexagonal phases M,In, (M = Gd, Tb, Dy, Ho, or Y: all belong to the W,Si, structure type) and Y21n (of the NiJn structure type).576 5 Thallium
Thallium(1rr) Compounds.-The electron-transfer reaction between T1' and ~ ~the Tl"' in the presence of Ce'" proceeds via T1" as an i n t e ~ m e d i a t e . 'In absence of such one-electron oxidants, two electrons are transferred from the T1' to the Tl"' in a single step. TI"' behaves as a one-electron oxidant towards oxalic acid in aqueous H 2 S 0 4in the dark.578Evidence has been presented for the presence here also of T1". Oxidation of AS'" by T1"' in HClO4 solution is inhibited by C1-, and the reactivity of the various thallium species is in the order T13+>T1C12' > TlCl: > TlC1, > TlCl;.579 Oxidation proceeds by way of an intermediate complex between Tl"' and AS'". The crystal structure of Me,TlCl reveals that it is built up essentially from discrete, linear Me,Tl' ions and Cl-.580The T1 is approximately octahedrally co-ordinated, with two C's at 2.139 A and 4 Cl's at 3.029 A. Thallium-containing adducts isolated from reactions between bridged olefins such as benzonorbornadiene or norbornene and Tl(OAc),-, (N,), have been characterized, e.g. (79; X = OAc or N3).581 A number of anionic T1"' complexes containing terdentate ligands have been prepared.'" Examples are R2TlL-, where R = Me or Ph, L = Aat or Sat [the compounds H,Aat and H,Sat being 4-(2-benzothiazolinyI)-2-pentanone and 2-(o-hydroxyphenyl)benzothiazoline, respectively]. The idealized structure of the Aat'- complex is (80).
"' J .
H. C . Hogg and H. H. Sutherland, Acta Cryst., 1973, B29, 2483.
"' H. H. Stadelmaier. J . D. Schobel, R. A . Jones. and C . A. Shumakcr. Acta Cryst.. 2926. 5 7 h E. Franceschi. J. Less-Common Metals, 1974, 37, 157. 577 G . Wada and K. Tamaki, Bull. Chem. SOC. Japan, 1974. 47, 1422. 5 7 x V. S. Srinivasan and N . Venkatasubramanian, Indian J. Chem., 1973, 11, 702. 5 7 ' ) P. D. Sharma and Y. K. Gupta, Austral. J. Chem.. 1973, 26, 21 1.5. '"' H.-D. Hausen, E. Veigel, and H.-J. Guder, Z . Naturforsch.. 1974. 29b, 269. -"' E. Maxa, G. Schulz, and E. Zbiral, Annalen, 1974, 933. "' L. Pellerito, R . Cefalu, and G . Ruisi, J. Organometallic Chern., IY73, 63, 41.
1973, R29,
185
Elements of Group 111
(79)
(80)
The vibrational spectra of the anions Me3TlCN- and (Me3Tl),F- may be The T1-F-T1 assigned in terms of C3uand D,, symmetries, re~pectively.'~~ bridge in the latter, therefore, must be linear. A number of cyclopentadienyl and indenyl derivatives of Tl"' have been rep~rted.~*~.~~~ Reduction of (C,H,)Tl"'Cl by the Na salt of naphthalene gives (C,H,),Tl,--containing one Tl"' and one T1' atom.s86 A thin film of TlN, formed from Tl+N, by reaction during cathode sputtering, has the hexagonal, wurtzite The oxide of thallium T140, may be formulated as T1:Tl'1'03.588The Tl"' atoms are situated at the centres of distorted T10, octahedra, while the T1' atoms are of 3 types, placed between parallel double lines of Tl"'0, units. In each case the T1' lone pair is stereochemically significant. Ba,Tl,O, forms orthorhombic crystals, isotypic with Ca2Fe205.589 The complexes TI[(TT-C~H~)M(CO),]~ (M = Cr or Mo) and Tl(.rr-C,H,)Cr(CO), have been prepared in quantitative yield by the reaction of [(.rr-C5H5)M(CO),],with metallic Tl.590 Thallium(1) Compounds.-T1' in the gas phase may be generated using hexafluoroacetylacetonatothallium(1)as precursor.591The T1' ion has been shown, mass spectrometrically, to form 1: 1 complexes in the gas phase with the following ligands: EPh, (E = P, As, or Bi), 1,lO-phenanthroline, 2,2'and 4,4'-bipyridyl, and phenanthrene. Some 'T1 n.m.r. spectra have been reported for T1' ions in aqueous The relaxation (longitudinal and transverse) of the T1 ions is independent of the resonance frequency, isotopic substitution of the solvent, salt concentration, or nature of the anions. It is very sensitive to 5x3
s84 s85
58h 587
*" 58y
s90
"'
s92
T. Ehemann and K. Dehnicke, J. Organometalfic Chem., 1974, 71, 191. N. Kumar, B. L. Kalsotra, and R. K. Multani, J. Inorg. Nuclear Chem., 1973, 35, 429.5. N. Kumar, B. L. Kalsotra, and R. K. Multani, J. Inorg. Nuclear Chem., 1974, 36, 1157. N. Kumar and R . K . Sharma, Chem. and I n d . , 1974, 261. G . V. Samsonov, A . N . Pilyankevich, A . F. Andreeva, and L. R. Shaginyan, Doklady Chem., 1973. 213, 844. R. Marchand and M . Tournoux, Compt. rend., 1973, 217, C, 863. R. von Schenck and H. Muller-Buschbaum, Z. anorg. Chem., 1974, 405, 197. H . Behrens, J. Ellermann, P. Merbach, and P. Weps, Z . Naturforsch., 1974, 29b, 469. H. Nakayama, C. Nishijima, and S. Tachiyashiki, Chem. Letters, 1974, 733. S. 0. Chan and L. W. Reeves, J. Amer. Chem. SOC.,1974, 96, 404.
Inorganic Chemistry of the Main-group Elements dissolved O,, however, and it has been concluded that in oxygen-free solutions T1' is mainly relaxed by transient spin-rotation interaction, and in oxygenated solutions by electron-nuclear dipole-dipole interaction. No T10, complexing need be postulated, however. TIN, is tetragonal at room temperature, but at 248*5 K it undergoes a transition to an orthorhombic form.5y3 1.r. and Raman spectra of a single crystal of TINO,-111 are consistent with the crystal space group being D:E-Pbnrn, with the NO; ions occupying sites of C, symmetry in the xy-planes and also perpendicular to them.594 Tl4P4O,, forms tetragonal crystals, in which the TI atoms are surrounded by 6 oxygen atoms in a distorted octahedral arrangement (Tl-0 distances 2.70-3.18 The two T1 atoms in the unit cell of T1' L-ascorbate are 4 . 0 5 A apart, bridged by 0 atoms.596 A new T1' uranate, Tl4UO5, has been made by careful heating of Tl,CO, + UO, under N,."' It dissociates above 230 "C to T1,O + T12U04,and it has been characterized by X-ray powder diffraction. The crystal structure of Tl(ZnS0,Cl) is built up from infinite layers of composition (ZnSO,Cl):-, held together by TI' ions.598The T1' ions are surrounded by 3 C1 and 6 oxygen atoms in an irregular manner (TI-Cl distances between 3.20 and 3.30 A, 5 T1-0 within the range 2.91-3.24 A, with the sixth 0 at a distance of 3.38A). Lattice constants have been tabulated for the ternary chalcogenides TlMX2, where M = Al, Ga, or In, X = S; or M = A1 or Ga, X = Se.599 Similar data have been recorded for T14GeS4,Tl,GeS,, and T1,Ge,S5.'"" TlFeS, and TlFeSe, may be prepared by melting together suitable ratios of the components to 300-500 "C.""' The T1-S distance in the former was found to be 3.314 A, as expected for an ionic interaction T1'- - .S2-. Two new modifications of TIInSz were formed by heating the I-form to high temperatures and pressures.6o2The 111-form has a structure consisting of sulphur layers (. . .ABBA.. .), with all the octahedral sites occupied by In, and 4 of the trigonal-prismatic sites by T1. The basic structural unit of T1' dimethyldithiocarbamate, T1S2CNMe2,is dimeric, and these units are joined by T1-S co-ordination to give layers parallel to the ab plane.6o3The TI atoms are seven-co-ordinate.
186
"" 4y4
""
Ty7 5yR
'" 'OO '("
'')'
"''
F. A . Mauer, C. R. Hubbard, and T. A. Hahn, J. Chem. Phys., 1973, 59, 3770. D. E. Pogarev and A. A. Shultin, Soviet Phys. Cryst.. 1Y73, 18, I Y 3 . J. K. Fawcett, V. Kocman, and S. C. Nyburg, Actu C r y s t . , 1974. B30, 1979. D. L. Hughes. J.C.S. Dalton, 1973, 2200. A . S. Giridharan, M. R. Udupa. and G. Ararnavudan, Z. anorg. Chem.. 1974. 407, 345. B. Bosson. A c t a Chem. Scand., 1973, 27, 2230. D. Muller, F. E. Poltmann, and H. Hahn, Z. Naturforsch., 1974, 29b, 117. G. Eulenberger and D. Muller, Z. Naturforsch., 1974, 29b, 118. A. Kutoglu, Naturwiss., 1974, 61, 125. K.-J. Range, G. Engert, W. Muller, and A. Weiss, Z. Naturforsch., 1974, 29b, 181. P. Jcnnische and R. Hesse, A c t a Chern. Scand., 1973. 27, 3531.
Elements of Group I11 187 A very similar situation is found for diethylthioselenophosphinatothallium(I), Tl(Et,PSeS) .604 Again the molecules are dimeric and linked together to give polymeric layers. The dimeric unit is shown in Figure 25. Crystals of TlF are orthorhombic, belonging to the space group Pm2a.605 There are two types of TI atom with unsymmetrical environments, showing that there are significant lone-pair distortions in this system.
Figure 25 The molecular structure of the [Tl(Et,PSeS)], dimer (Reproduced by permission from Acta Chem. Scand., 1973, 27, 3355) Analysis of the electron scattering by the TlF dimer suggests a value for the instantaneous dipole moment of several debye.606This is not consistent with a stiff, symmetric, linear structure for the dimer. Pure TlMnF, can be obtained in good yield from solutions of excess TlF and MnF, in dilute HF.607 Thallium(1) forms precipitates (TlX) and soluble complexes (TlX;) with the anions C1-, Br-, I-, and Ng in dimethylacetamide as solvent. Formation constants have been calculated for all of these species.6o8 Thallium(1) tetracarbonylcobaltate has been prepared by metathesis of Na[Co(CO),] with T1' salts in H20, by metal exchange, Hg[Co(CO),], + 2T1, Other T1' compounds, e.g. and by reduction of Tl[Co(CO),], by T1 Tl[M(CO),Cp] (M = Cr, Mo, or W), have also been isolated, while there is spectroscopic evidence for the existence of TI[CO(CO)~PP~,]and Tl[Mn(CO),]. The stabilities of these TI' compounds towards disproportionation are in the order: Co(CO), >> M(CO),Cp (W > Mo > Cr) > Co(CO),PPh, - Mn(CO),. All of the T1"' analogues are known, but some of h04 h05 'I'
S. Esperis and S. Husebye, Acta Chem. Scand., 1973, 27, 3 3 5 5 . N. W. Allcock and H. D. B. Jenkins, J.C.S. Dalton, 1974, 1907. M. G. Fickes, R. C. Slater, W. G. Becker, and R. C. Stern, Chem. Phys. Letters, 1974, 24, 10.5.
'07
6OR 'OY
G. S. Rao and S. K. Gupta, Indian J. Chem., 1973, 11, 956. M. Brkant, J.-P. Nicolas, S. Alam, and M. Levergne, Compt. rend., 1973, 277, C, 85.5. J . M. Burlitch and T. W. Theyson, J.C.S. Dalton, 1974, 828.
188
Inorganic Chemistry of the Main -group Elements
them, especially Tl[Mn(C0)5]3, readily undergo light-promoted reductive elimination to the corresponding T1' compound. The crystal structure of TlCo(CO), as determined by X-ray diffraction, consists of discrete T1' and [Co(CO),]- ions arranged in an NaC1-like array.61nIn low-dielectric solvents, however, TlCo(CO), exists as a tight ion pair, with some TI-Co covalent bonding. With excess [Co(CO),]-, the complex Tl[Co(CO),]; is formed. In solvents of high dielectric constant, the reactions of TlCo(CO), are consistent with the presence of free ions. Tl,HgBr, crystallizes in the tetragonal space group P4/rnnc. HgBr, octahedra are present, with interstitial TI' ions.'" Tl,HgCl, could not be prepared, Tl,,Hg,Cl,, always being produced. Reduction of (CsHs)Tl"'C1 with potassium metal gives K'[CsH,T1']-."" Phase studies on T1' systems have been reported in refs. 613-624.
Other Thallium Compounds.-Tl'' ions may be generated by flash photolSome of their redox reactions have been studied, ysis of Tl'l' and they give values of the standard reduction potentials for the reactions:
+ e- e TI2+ T12' + e- e T1' Tl"
of +0.33 f0.05 and +2.22 f0.05 V, respectively. The disproportionation reaction :
has a rate constant of (5.5 f0.5) x 10, 1 mol-' s-l at 25 "C. Further studies on the T12' ion, similarly produced, including rate constants of a number of its reactions, have also been reported by Schwarz et a1.626 610
6"
612 613
'I4
'I5 6'6
618
'Iy hZ(1
621
"*
''' 024
'*' 626
D. P. Schussler, W. R . Robinson, and W. F. Edgell, Inorg. Chem.. 1974. 13, 153. K. Brodersen, G . Thiele, and G . Giirz, 2. anorg. Chem., 1973, 401, 217. N . Kumar and R . K. Multani, J. Organometallic Chem., 1973, 63, 47. A. Schiraldi, A . Magistris, and E. Pemati, Z. Naturforsch., 1Y74, 29a, 782. C. W. F. T . Pistorius, J. Chem. Phys., 1974. 60,3720. 1. N . Belyaev, T. G. Lupeiko, and G . P. Kirii, Russ. J. Inorg. C h e w , 1973, 18, 71 1. M . S. Kabre, M. Julien-Pouzol, and M. Guittard. Bull. SOC.rhim. France, 1974, 1881. J.-C. Cretenet, Rev. Claim. minirale, 1973, 10, 399. A. Vedrine, R. Boutonnet, and J.-C. Cousseins, Compt. rend., 1973, 277, C, 1129. H . J . Seifert. T. Krimmel. and W. Heinemann. J. Thermal Analysis. 1974. 6, 175. V . V . Safonov, V . A. Grin'ko, M . B . Varfolomeev, €5. S. Malysheva, and V . I . Ksenzenko. Russ. J. Inorg. Chem., 1973, 18, 1503. V. V . Safonov and 0. V. Lemeshko. Russ. J. Inorg. Chern.. 1973, 18, 1035. R . P. Lagutova, D. G. Barsegov, A. G. Yakovlev, and I . I . Il'yasov, Russ. J. Inorg. Chem.. 1973, 18, 760. V . V. Volchanskaya and I . 1. Il'yasov, Russ. J. Inorg. C'hom., 1973, 18, 1041. I . I . Il'yasov and Yu. G . Litvinov, Russ. J. Inorg. Chem., 1973, 18, 1788. B. Falcinella, P. D. Felgate, and G. S. Laurence, J.C.S. Dalton, 1Y74, 1367. H . A . Schwarz, D. Comstock, J . K. Yandell, and R . W. Dodson, J. Phys. Chem., 1974, 78, 488.
Elements of Group 111 189 The effect of C1- on the electronic spectrum of TI" produced by pulse radiolysis indicates that the species TlCl', T1C12, and TlCl; are all present. Rate constants for a number of reactions of these chloro-species have been rep~rted.~" The phase diagram of the TI-S system reveals the existence of the following phases: Tl,S, TLS,, TlS, and T1,S,.628TI& forms monoclinic crystals in which one Tl"' atom is tetrahedrally co-ordinated by S atoms, and also interacts with 3 T1' ions.629This interaction is thought to be electrostatic in nature. 627 628 629
R . W. Dodson and H. A. Schwarz, J. Phys. Chern.,,1974, 78, 892. S. Kabre, M. Guittard, and J . Flahaut, Compt. rend., 1974, 278, C, 1043. B. Leclerc and M. Bailly, Acta Cryst., 1973, B29, 2334.
Elements of Group IV ~~~
BY P. G. HARRISON AND P. HUBBERSTEY
1 Carbon The limits pertaining to the inorganic chemistry of carbon are difficult to assess. Following the pattern adopted in previous Reports, the data collected here have been restricted to those describing the chemistry of the carbon allotropes and of the non-catenated molecular carbon species, particularly those containing carbon-non-metal (i.e. hydrogen, nitrogen, phosphorus, oxygen, sulphur, and halogen) bonds. The carbides are omitted since there are no published data on the Main-group element carbides; the carbaboranes are also omitted since they are considered in full in Chapter 3. A further section of Gmelin’s Handbook of Inorganic Chemistry relating to carbon has been published;’ in it the chemistry of partly or completely halogen-substituted derivatives of CH, CH,, and CH,, as well as the perhalogenated methanes, is described. Halogenomethanes containing hydrogen are not covered. A new technique for carbon analysis based on X-ray fluorescence has been devised.’ Although X-ray fluorescence of light elements such as carbon corresponds to energies too low to be excited by classical equipment, by using a mixed photon-slow-electron tube, longer wavelengths ( >20 A), suitable for light-element excitation, can be achieved without notable technological constraint. It has .been concluded3 from the results of chemical analytical experiments that much of the carbon found in lunar soils has been modified since accumulation by the energetic events that cycle lunar soils; i.e. the rate at which extralunar carbon is accumulated from the solar wind and meteorite bombardment is slow compared to that at which it is redistributed by particle erosion and aggregation. A number of theoretical investigations of the electronic structures of small carbon-containing molecules have been ~ n d e r t a k e n The . ~ ~ relative Gmelin’s Handbook of Inorganic Chemistry, System 14, Carbon Part 11, Section 2, SpringerVerlag, Berlin, 1974. * R. vie le Sage, P. Bocquillon, and J. Faucherre, Cornpt. rend., 1974, 279, C, 125. D. J. Desrnaryis, J. M . Hayes, and W. G. Meinschein, Nature. Phys. Sci.. 1974. 246, 6 5 . V. I. Nefedov, N. P. Sergushin, I. M. Band, and M. B. Trzhaskovskaya, J. Electron Spectroscopy, 1973, 2, 383. ’ W. B. Perry and W. L. Jolly, Inorg. Chew., 1974, 13, 121 1. D. R. Armstrong, P. G. Perkins, and J. J. P. Stewart, J.C.S. Daiton, 1973, 2273.
‘
190
191
Elements of Group IV
intensities of X-ray photoelectron spectra (X.P.S.) bands corresponding to, inter alia, carbon and silicon core electrons have been calculated and compared with experimental values ;4 satisfactory agreement is obtained for the 1s levels in, inter alia, CF,, CO, COz, and CO:-. Experimentally determined core-electron binding energies have been correlated with calculated charge distributions for compounds of carbon (Is), silicon ( 2 p ) , and germanium (3p,,J.’ Carbon (1s) binding energies vary from 290.31 for C(CH,), to 301.68 eV for CF,. Calculations have been performed within the CNDO MO SCF framework on a wide range of molecules containing elements of the first and second rows of the Periodic Table, including carbon and silicon6 Valencies of all atoms, anisotropies (a measure of the non-spherical distortion of an element’s electronic environment) of some of the atoms, and bond indices for bonds in selected molecules have been calculated. Appropriate data are collected in Table 1. The valeocy of Table 1 Valencies, anisotropies, and bond indices in carbon -containing rno lecules Carbon valency 2.94 2.61 3.86 3.93 3.95 3.94 3.98 3.98 4.00 3.53
Carbon anisotropy 0.74 0.82 0.00 0.02 0.00 0.04 0.16 0.00 0.00 0.25
Bond C-N c-0 c-0 c-0 C-H
C-B
c-0
Bond order 2.94 2.61 1.93 1.31 0.99
1.oo 2.38
carbon in most of the compounds studied is calculated to be ca. 3.9 (Table 1); notable exceptions are CN- and CO, where values are 2.9 and 2.6, respectively. The latter values and their tendency to increase account for the donor properties of these species and their ability to complex to transition-metal ions. It is noteworthy that both nitrogen and oxygen in these species have high valencies; hence the mode of attachment of CO in metallic carbonyls is not surprising.6 Carbon Allotropes.-Thermodynamic functions of single-crystal graphite have been assessed in the t’emperature range 0-3000 K7The experimental specific .heats have been described by a computer-fitted single equation; enthalpies, entropies, and free energies have also been calculated. Galimov’s cavitation hypothesis’ for the formation of natural diamonds has been refuted by Frank et al.” on the basis of the kinetics of crystal
’ N . V. Markelov, V. I. Volga, and L. M. Buchnev, ’ E . M . Galimov, Nature, 1973, 243, 389.
’ F. C. Frank, A. K. l,ang,
Russ. J . Phys. Chem., 1973, 47, 1025.
and M . Moore, Nature, 1973, 246, 143.
192
Inorganic Chemistry of the Main-group Elements growth and martensitic conversion. It is conceded, however, that although it is inconceivable that the recognized diamonds for which mines are worked were produced by Galimov’s process, the formation of microdiamonds by this process is possible. The postulate” that natural diamonds were formed by a reduction of CO, by pyrrhotite in reactions such as (1) has been tested experimentally by oxidizing natural diamonds by pure oxygen at high temperature .” 2FeS(c) + CO,(g) + 2FeO(soln.) + S,(g) + C(diamond)
(1)
Diamonds formed by this route would contain inclusions containing either free sulphur, or sulphur compounds7 or both; on oxidation, gaseous sulphur oxy-compounds would be formed, which could be detected mass spectrometrically. No evidence of sulphur was found, and so this proposed route to natural diamond is not thought to be responsible for the formation of all natural diamonds. The data are limited by the amount of diamond oxidized (16g), and so the possibility of some diamond formation by this route cannot be ruled out.” A new method of nucleating synthetic diamonds in the size range CH2F+> CF; > CH;
The production of negative ions from CH,X (X = Br, I, CN, or NO,) by both thermal electron attachment and electron capture from excited atoms has also been studied.I2' Hydrolysis of CF,C14-, (0 S n d 4) has been investigated in the temperature range 30-500 "C and pressure range 10-4000 atm.LZZ No reaction was observed with CF, or CF,C1. Although CCl, undergoes simple hydrolysis (16), that of CFC1, and CF2C12is thought to occur v i a randomization (17) and subsequent hydrolysis of CC1, (16). The denitration of CH3N02, CCl, 3CF,Cl,
-+
+ 2H,O
-+
CO, + 4HC1
CC1, + 2CF3Cl; 2CFC1,
-+
CCl, + CF,Cl,
(16) ( 17)
induced by hydroxyl radical, has been examined by Eiben."' Addition of the radical (produced by irradiation of the solution) to a c i -nitromethane, CH,=NO;, the predominant form of nitromethane above p H = 10, leads to the transient anion of hydroxynitromethane, HOCH,NO,, as shown in reaction (1S), which decays via disproportionation (19). The oxidized CH3N02 2HOCH,NO,
CH,=NO; OH-\HOCH,NO,
e HOCH,NO, + HOCH,NO:-
(18)
(19)
product HOCH,NO, decomposes to yield nitrous acid and formaldehyde (20); the reduced product probably protonates and eliminates H 2 0 to form HOCH2N0,-+ H,CO + HNO, HOCH2NO:-
-:: HOCH2N0 >
(20) (21)
hydroxynitrosomethane as shown in reaction (2l).123 Thermal decomposition af both CH41242125 and CC1,NO'26 has been investigated under differing conditions. Although NO, CCl,, CCl,N=CCl,, CCl,NO,, NOCl, and COC1, were identified as products of the CC1,NO pyrolysis, the previously reported product, CCl,N(O)=CCl,, was not positively identified.lZ6 ''(I 121
lZ3
R. J. Blint, T. B. McMahon, and J . L. Beauchamp, J. Amer. Chem. SOC.. 1074, 96, 1260. J. A. Stockdale, F. J. Davis, R. N. Compton, and C . E. Klots, J . Chern. Phys., I Y 7 4 . 60, 427Y. A. P. Hagen and E. A. Elphingstone, J. Inorg. Nuclear Chem., 1974, 36, 509. K. Eiben, Z . Naturforsch., 1974, 29b, 562. K . I. Makarov and V. K. Pechik, Carbon, 1974, 12, 391. G. A. Vompe, Russ. J. Phys. Chem., 1973, 47, 788. B. W. Tattershall, J.C.S. Dalton, 1974, 448.
Elements of Group IV
211
The production of hydrocarbons from CH,OH was achieved for the first time when it was heated (< 190 "C) in phosphorus pentoxide, polyphosphoric acid, or combinations thereof About 200 hydrocarbons were obtained in ca. 36-39% yield. The discovery is remarkable because CH30H does not form an alkene and yet must proceed from a one-carbon compound to multi-carbon units. Two interpretations of the reaction mechanism, based on either the five-co-ordinate carbon atom of Olah or carbene as intermediates, have been proposed.lZ7 The primary products found in the radiolysis of liquid CH,0H'28s'29and of aqueous solutions of CH3CN,I3' CHC13,131and Cc1,"' have been examined. Those observed in liquid CH30H are the CH30' and 'CH,OH radical^.^^^*^^^ Although 'CCl, radicals are found in the radiolysis of both CHCl, and CC1, solutions, 'CHC1, radicals are also believed to be formed in the former solutions .I3' Trifluoromethyl peroxynitrate, CF,OONO,, has been obtained in high yield by the reaction of CF,OOH with N,O, or C F 3 0 0 F with N,04."' Its CF3OOH + N205
--j,
CF3OON02 + HNO,
(22)
physical and chemical properties are reported together with an assignment, based on C3 symmetry, of its vibrational spectra.13' Reaction (24) has been CHC1, + F2S03+ CHCl,OSO,F
+ ClF
(24)
st~died.',~Although ClF is quoted as a reaction product, it was not positively detected, presumably because of reaction with the glass reactor exit. A small amount of CC1,F was also obtained as a b y - p r ~ d u c t . ' ~ ~ Several papers have been published describing donor-acceptor interactions in systems involving both CH,"" and its substituted d e r i ~ a t i v e s . ~ ~ ~ - ~ ~
I*'
Izy "" 13'
13'
'31 13* 139
''" 14' '41
143
D. E. Pearson, J.C.S. Chem. Comm., 1974, 397. F. P. Sargent, E. M. Cardy, and H. R . Falle, Chem. Phys. Letters, 1974, 24, 120. S. W. Mao and L. Kevan, Chem. Phys. Letters, 1974, 24, 505. I. Dragonit, Z . Dragonit, Lj. Petkovit, and A. Nikolit, J. Amer. Chem. SOC., 1973, 95, 7193. B. Lesigne, L. Gilles, and R. J . Woods, Canad. J. Chem., 1974, 52, 1135. F. A. Hohorst and D. D . DesMarteau, Inorg. Chem., 1974, 13, 715. L. F. Cafferata and J. E. Sicre, Inorg. Chem., 1974, 13, 242. V. A . Koroshilov and E. B. Bukhgalter, Russ. J. Phys. Chem., 1973, 47, 1348. R. T. Yang and M. J . D. Low, Spectrochim. Acta, 1974, 30A, 1787. G . R. Choppin and J. R . Downey, Spectrochim. Acta, 1974, 30A, 43. M. A. Hussein and D. J. Millen, J.C.S. Faraday Ir, 1974, 70, 685. D.J . Millen and G. W. Mines, J.C.S. Faraday 11, 1974, 70, 693. N. F. Cheetham, I . J. McNaught, and A. D. E. Pullin, Austral. J. Chem., 1974, 27, 973. N . F. Cheetham, I. J. McNaught, and A. D. E. Pullin, Austral. J. Chem., 1974, 27, 987. I. J . McNaught and A. D. E. Pullin, Austral. J. Chem., 1974, 27, 1009. V. P. Anferov, V. S. Grechishkin, and M. Z . Yusupov, Russ. J. Phys. Chem., 1973,47,713. H . Langer, H . C. Hertz, and M. D . Zeidler, Chem. Phys. Letters, 1973, 23, 417. T. N . Naumova, T. S. Vvedenskaya, L. S. Zhevnina, and B. D . Stepin, Russ. J. Phys. Chem., 1973, 47, 1257.
212
Inorganic Chemistry of the Main-group Elements
Evidence for these interactions is usually obtained from analyses of spectroscopic data. Thus, interactions between CH4,13,CH30H,I3' CHC13,136 and H 2 0 have been verified. Donor-acceptor complexes between CH30H,'37s'38 ~ ~ ~ ~ ~ , 1 3~~~1,139-141 9.140 and a number of amines have been studied; the stability of the donor-acceptor bond has been found to increase with increasing substitution of the amine.'37.'38Interactions between CHCl, and a number of organic molecules, including CH,CN and (CH3CO>,O,"' between CCl, and C2HsOH,143 and between CCl, and SO,Cl,'"" have also been investigated to elucidate the interaction mechanisms. Formaldehyde and its Substituted Derivatives.-Formaldehyde, Carbonyl Halides, etc. Despite the general decrease in the number of publications in this field, the high proportion describing the spectroscopic properties of these molecules has been maintained; these, together with the corresponding publications for formic acid and formates, are collected in Table 9. The
Table 9 Spectroscopic studies of formaldehyde and its substituted derivatives Spectroscopic technique Microwave 1.r.
Raman U.V. Photoelectron
Molecules examined HCO;" F,CO;b F,CS;' H(NH,)CO;d H(NH,)CS.' H,CO;'." D,CO;"." CI(CX,O)CO ( X = H or D);' HC0,H;' DC0,D;' y-Ca(HCOO),;k p - and S-Sr(HCOO),.k H,CO;'.' HDCO;' D,CO;' CI(CX,O)CO ( X = H or D);' Ca(HC00)2.m D,CO;" CI,CS;p HCO,H.q H,CO (X.P.S.);' X(F,CS)CS (X = F, C1, or SCF,) (U.P.S.)'
ref. 149; ref. 145; ref. 146; ref. 147; ref. 148; A . Khoshkoo, S. J. Hemple, and E. C. Nixon, Spectrochim. Acta, 1974, 30A, 863; J. W. C. Johns and A. R. W. McKellar, J. Mol. Spectroscopy, 1973, 48, 354; S. Tatematsu, T. Nagakawa, K. Kuchitsu, and J. Overend, Spectrochirn. Acta, 1974, 30A, 1585; ' J . E. Katon and M. G. Griffin, J. Chem. Phys., 1973, 59, 5868; H, R. Zelsman and Y. MarCchal, Chem. Physics, 1974, 5, 367; li B. F. Mentzen and C. Comel, Spectrochim. Acta, 1974, 30A, 1263; ' A. Chapput, B. Roussel, and G. Fleury, J . Rarnan Spectroscopy, 1973, 1, 507; R. S. Krishnan and P. S . Ramanujam, J. Rarnan Spectroscopy. 1973, 1, 533; B. J. Orr, Spectrochim. Acia, 1974. 30A, 1275; D. C. Moule and C. R. Subramanian, J. Mol. Spectroscopy, 1973, 48, 336; T. L. Ng and S. Bell, J. Mol. Spectroscopy, 1974, 50, 166; ' T. X. Carroll and T. D. Thomas, J. Electron Spectroscopy, 1974, 4, 270; ' H. Bock, K. Wittel, and A. Haas, Z . anorg. Chem., 1974, 408, 107.
a
molecular geometries of F 2 C 0 (15),14' F,CS (16),'46H(NH,)CO (17),'"' H(NH,)CS (18),14' and the HCO radical have been determined from their microwave spectra. The effect of substituting S for 0 in both F,CO and H(NH2)C0 is minimal since the C-F and N-C bond distances and the LFCF and LXCN ( X = O or S) in the comparable molecules are in agreement within experimental error. The dipole moment of F2CS, which at was prepared by pyrolysis of tetrafluoro-1 ,3-dithietan, S-CF,-S-CF,, I
'41
I47 '41
I
J. H. Carpenter, J . Mol. Spectroscopy, 1974, 50, l X 2 .
A. J. Careless, H. W. Kroto, and B. M. Landsberg, Chem. Physics, 1973, 1, 371. E. Hirota, R. Sugisaki, C. J. Nielsen, and G. 0. Sorensen, J. Mol. Spectroscopy, 1974, 49, 25 I . R. Sugisaki, T. Tanaka, and E. Hirota, J. Mol. Spectroscopy, 1974, 49, 241.
213
Elements of Group IV F \1.3
F
\ 1.3lS(lO)
166(10)
0
F' (1 5)
(17)
(18)
All distances/A.
500 "C in a quartz tube, has been calculated to be 0.080 D.'"" The geometry is compared with experimentally and theoretically of the HCO derived geometries of H2CO"' in Table 10; the major changes observed in the experimental data on formation of the radical are an increase in LHCO and a slight decrease in r(C-0). The calculated bond lengths of H,CO are shorter than those determined experimentally; the deviation is consistent Table 10 Molecular geometries of HCO and H 2 C 0 HCOI~~
H,CO (theor.)'" H,CO ( e ~ p t . ) ' ~ '
r(C-O)/A 1.17 1.1781 1.203
r(C-H)/A 1.11 1.0924 1.101
LHCO 127" 122'3' 121'44'
with the general observation that Martree-Fock calculated bond lengths are usually shorter than experimental values, whereas Hartree-Fock calculated bond angles are very a~curate.'~' Three other theoretical investigations of H 2 C 0 have been e f f e ~ t e d ; l ~ ' the - l ~ ~data obtained are compared with those for D,CO"' and H,CS."' Two independent theoretical analyses of the hydrogen bond in H2CO-H20 dimers have also been ~ n d e r t a k e n , ~ ~ ~ . ~ ' ~ The kinetics of the oxidation of formaldehyde have been determined in two separate s t ~ d i e s . l ~Data ~ , l obtained ~~ using the newly discovered Mo-0-S catalysts indicate that the catalyst dissociates the H2C0 [equation ( 2 5 ) ] HZCO + CO + H2
(25)
J. A. Austin, D. H. Levy, C. A. Gottlieb, and H. E. Radford, J . Chem. Phys., 1974,60, 207. W. Meyer and P. Pulay, Theor Chim. Acta, 1974, 32, 2.53. I T ' E. S. Yeung and C . B. Moore, J. Chem. Phys., 1974, 60, 2139. Is' P. J. Rruna, S. D. Peyerimhoff, R. J . Bucnker. and P. Rosmus, Chem. Phystcs, 1974,3,35. ' 5 3 J . L. Duncan and P. D. Mallinson, Chem. Phys Letters, 1973, 23, 597. J. E. Del Bene, Chem. Phys. Letters, 1973, 23, 287. Is5 W. R . Wolfe and K. B. Keating, J. Electrochem. SOC., 1974, 121, 1125. '" A. K. Wadhawan, P. S. Sankhla, and R. N. Mehrotra, Indian J. Chem., 1973, 11, 567. '49 15"
Inorganic Chemistry of the Main -group Elements
214
with subsequent oxidation of the CO and HZso formed.155The mechanism [reactions (26)-(30)] of the oxidation of H,CO by Ce" in aqueous NO; CelV
H*O
L CeOH'++H+
CelV+ NO,
H
\
/O'
+ Ce'"
[Ce(N03)]"
___f
HC0,H
+ Ce'" + H'
(26) (27)
(30)
H
has been formulated, with reaction (29) as the rate-determining step. The reaction of H,CO with active oxygen gives rise to a chemiluminescence which has been attributed to the electronic transitions of HO, radicals produced in reaction (31)."' The kinetics of the oxidation of formyl radicals by oxygen atoms [reaction (32)] have also been s t ~ d i e d . ' ~ '
CHO +o:+.HO:
+ co
CO+OH +- CHO+O --$ CO,+H
( 3 1)
(32)
Thermal decomposition of H,CO in the presence of NO has been studied at 500°C.159The results indicate that the pyrolysis is initiated by reaction (33) and involves the chain-carrying step (34).
NO + H,CO
-+HNO
+ CHO
2 H N 0 +. N, + 2 0 H
(33)
(34)
18F exchange between F,CO and Group I fluorides (LiF-CsF) has been studied to ascertain the effect of dipolar aprotic Exchange varies in the order Cs> Rb >> K > Na, Li at 423 K (Cs > Rb >> K, Na, Li at 323 K), and is enhanced in the presence of acetonitrile or diglyme but not benzene or ether. 'sI
K. H. Becker, E. H. Fink, P. L*angen, and U. Schurath, Z . Naturforsch., 1Y73, 28a, 1872.
N.Washida, R. I. Martinez, and K. D. Bayes, 2. Nahtrforsch., 1974, 29a, 251. "" ""
K. Tadasa, N. Imai, and T. Inaba, Bull. Chem. SOC. Japan, 1974, 47, 548. C . J . W. Fraser, D. W. A . Sharp, G. Webb, and J. M . Winfield, J.C.S. Dalton, 1074, 112.
Elements of Group IV 215 Formic Acid and Formutes. A theoretical and experimental ('H n.m.r.) investigation of ionic solvation in HCO,H has been undertaken.161 Calculations for the C1O;-HC0,H system indicate small solution energies, very small changes in molecular geometries as a result of solvation, and higher solvation numbers for C10; than for monatomic ions. These conclusions have been verified by the experimental data.16' Analysis of the results obtained in the photoionization of HCOzH has led to a value of AH*(HCO,g) = 10.2 kcal mol-' 16' (cf. 9.9 kcal mol-' derived from the photoionization of H2CO). A kinetic study of the reaction of formate and peroxydisulphate in aqueous solution [reaction (35)] has been made.163A mechanism has been proposed based on a chain reaction involving SO:, OH; and CO; radicals. S,O:-+HCOO- + 2SOi-+H++CO,
(35)
The crystal structures of potassium d i t h i ~ f o r m a t e 'and ~ ~ ammonium carbamatei6' have been determined; K(HCS,) is tetragonal (a = 10.596, c = 7.946 A), NH,C0,NH2 is orthorhombic, (a = 17.121, b = 6.531, c = 6.842A). The carbamate ion is planar; the bond angles and distances (corrected for thermal libration) are shown in diagram (19).'"
(a) Bond distances/A
(b) Bond angles
(19)
Derivatives of Group VI Elements.-Oxides, Sulphides, and Related Species. With the exception of the oxidation of CO, surprisingly little interest has been shown in the inorganic chemistry of these molecules during the period of this Report; as a result of this paucity of data, the molecules will not be considered individually, as in previous Reports. Theoretical calculations of the electronic structures of the unstable intercarbon suboxide C302,167.'68 and carbon monoxide dimer mediate C20,166 C20,'69 have been carried out. It has been concluded that C20, can be bound (with respect to two CO molecules) and will exist as a ground-state 16' lh2
163 164
166
I67 168 169
B. M. Rode, Monatsh., 1974, 105, 308. P. Warneck, Z . Naturforsch., 1974, 29a, 350. M. Kimura, Inorg. Chem., 1974, 13, 841. R. Engler, G. Kiel, and G. Gattow, 2. anorg. Chem., 1974, 404, 71. J. M. A d a m and R. W. Small, Acta Cryst., 1973, B29, 2317. C. Thomson and B. J. Wishart. Theor. Chim. Acta, 1973, 31, 347. H. H. Jensen, E. W. Nilssen, and H. M. Seip, Chem. Phys. Letters, 1974, 27, 338. R. D. Bardo and K. Ruedenberg, J. Chem. Phys., 1974, 60, 932. N . H. F. Beebe and J. R. Sabin, Chem. Phys. Letters, 1974, 24, 389.
216
Inorganic Chemistry of the Main-group Elements triplet (3Z).1"9The state formed from two ground-state C O molecules is repulsive, however, and, in order to produce C,O, in a bound state, it will be necessary t o use one. excited C O Lipscomb"" has recently commented on a previous assignment of the crystal structure of a -CO. Krupskii et al."' assigned a disordered structure in the space group P a 3 , the space group P2,3 (of lower symmetry) being rejected on the basis that it is in conflict with the disorder required by the residual entropy. Lipscomb refutes the rejection of the P2,3 space group, stating that no contradiction need exist between the residual entropy and the choice of this space group. H e suggests that more accurate measurements are required o n the structures of a-CO and the isoelectronic a - N , before definite conclusions can be drawn.17" A number of investigations of the spectroscopic properties of these molecules have been described. The i.r. spectra of C0,172.173 C02,"4 and CS,'75have been investigated; the CO bond length, force constant, and i.r. band intensity of CO in the presence of strong electric fields have been analysed the~retically."~ The results have been applied to the interpretation of the i.r. spectra of weakly adsorbed CO on various surfaces and of CO in transition-metal carbonyl complexes. The U.V.spectra of free CO,"" CO chemisorbed o n MgO of high surface area,177 and C02"6 have been measured. The spectra of the chemisorbed species177are consistent with electron transfer and the development of conjugated adsorbed aromatic oxo car bon mions such as the (C0):- (4 d n =s6) species (20)-(22) o r open
conjugated structures such as (23). The U.P.S. of C0,179,180 C02,179COSe,"' CSSe,"' and CSei8' have been determined using H e I,'*' H e 11,179and Ne 17" 17' 172 17' 17'
17" 177
I78
""
''I
W. N. Lipscomb, J. Chern. Phys., 1974, 60, 5138. 1. N. Krupskii, A. 1. Prokhvatilov, A. 1. Erenberg, and L. D. Yantsevich, Phys. Status Solidi ( A ) , 1973, 19, 5 19. N . S. Hush and M. L. Williams, J. Mol. Spectroscopy. 1Y74, 50, 349. R. L. Amey, J. Phys. Chern., 1974, 78, 1968. S. Bihl, J.-P. Fouassier, and R. Joeckle, Cumpt. rend., 1974, 278, R , 107. A. G. Maki and R. LA. Sams. J. Mol. Spectroscopy, 1974, 52, 233. S. Ogawa and M. Ogawa, J . Mol. Spectroscopy, 1974. 49, 454. A. Zecchina and F. S. Stone, J.C.S. Chern. Cornrn., 1974, 582. T. K. McCuhbin, J. Pliva, R. Pulfrey, W. Telfair, and T. Todd, J. Mol. Spectroscopy, 1974. 49, 136. J. L. Gardner a n d J. A. R. Samson, J. Eleciron Spectroscopy, 1973, 2, 259. J. L. C a r d n e r and J. A. R. Samson, Chem. Phys. Letters, 1974, 26, 240. D . C. Frost, S. T. L.ec, and C. A. McDowell. J. Chern. Phys.. 1973, 59, 5484.
217
Elements of Group IV
11*0 radiation. A correlation diagram of ionic states, of CO:, CS:, CSe:, COS', COSe', and CSSe', has been produced .Ia1One particularly interesting trend emerges. The energy of each ionic state is lowered by substitution of a heavier end atom; the effect of substitution of S by Se is much smaller (C1 eV) than that of 0 by S or Se (>1eV). This reflects the well-established fact that the resemblance between two successive elements in a Periodic Group is closer as one proceeds down the Group.18' The Auger electron spectrum of C,O, has been recorded;'8z both COlS3and CS21a4have been subjected to electron-impact ionization studies, and COS has been studied by both and molecular beam electric resonance s p e ~ t r o s c o p y . ~ ~ ~ + ~ ~ ~ The reactions of a number of atoms (H, F, 0, S), radicals (OH), diatomic molecules (N2,02),and ions (He',Ne',H+,O-) with these molecular species have been studied; the systems examined are summarized in Table 11. Several reactions of CO with 0, OH, 02,and 0- are included in Table 11;
Table 11 Reactions of CO, CS, CO,, COS, and CS, with atoms, radicals, molecules, and ions that have been studied recently H+CO" H + COzb F + CO' 0 + Cod.'
0 + CVR 0 + C02" 0 + CS2'.' S+COS"
OH + CO' N, + COP 0, +Cog*' He* + CO"
He++ COzb Ne'+ COzh H' + COzb 0-+ co
H. Y. Wane, J. A. Eyre, and L. M. Dorfman, J . Chem. Phys., 1973, 59, 5199; M. J. Haugh and J. H. Birely, J. Chem. Phys., 1974, 60, 264; R. Milstein, R. L. Williams, and F. S. Rowland, J. Phys. Chem., 1974,78,857; E. C. Y. Inn, J. Chem. Phys., 1973,59,5431; E. C. Y. Inn, J . Chem. Phys., 1974, 61, 1589; H. T. Powell and J. D. Kelley, J. Chem. Phys., 1974, 60, 2191; N. Djeu, J. Chem. Phys., 1974,60,4109; S. C. Baker and A. M. Dean, J. Chem. Phys., 1974, 60, 307; ' I. R. Slagle, J. R. Gilbert, and D. Gutman, J . Chem. Phys., 1974,61, 704; J . Geddes, P. N. Clough, and P. L. Moore, J. Chem. Phys., 1974,61,2145; " R. B. Klemm and D. D. Davis, J. Phys. Chem., 1974, 78, 1137; C. J. Howard and K. M. Evenson, J . Chern. Phys., 1974, 61, 1943; D. D. Davis, S. Fischer, and R. Schiff, J . Chern. Phys., 1974,61, 2213; I. W. M. Smith and R. Zellner, J.C.S. Faraday 11, 1973, 69, 1617; R. A . Young and W. Morrow, J. Chem. Phys., 1974, 60, 1005; W. T. Rawlins and W. C. Gardiner, J. Phys. Chem., 1974, 7 8 , 4 9 7 ; C. H. Yang and A. L. Bedad, J.C.S. Faraday I, 1974, 70, 1661; M. A. Coplan and K. W. Ogilvie, J. Chem. Phys., 1974, 61, 2010; M. McFarland, D. L. Albritten, F. C. Fehsenfeld, E. E. Ferguson, and A. L. Schmeltekopf, J. Chem. Phys., 1973, 59, 6629. a
'
many other investigations of the oxidation of CO have been published during the period of this Report. The majority describe the catalytic effect of either metals (Mo,lE8Pd,lE9Pt,189p191 A,"') or oxides [Ti0,,lg2 Sn0,1x2
L. Karlsson, L. 0. Wcrme, T. Bergmark, and K. Siegbahn, J. Electron Spectroscopy, 1974, 3, 181. I w 3K. C. Smyth, J . A. Schiavone, and R. S. Freund, J. Chem. Phys., 1974, 60, 1358. IR4 M. Toyoda, T. Ogawa, and N. Ishibashi, Bull. Chem. SOC. Japan, 1974, 47, 95. 1x5 M. Bogey, A. Bauer, and S. Maes, Chem. Phys. Letters, 1974, 24, 516. lS6 R. E. Davis and J. S. Muenter, Chem. Phys. Letters, 1974, 24, 343. 187 J. M. L. J. Reinartz and A. Dynamus, Chem. Phys. Letters, 1974, 24, 346. S. J . Atkinson, C. R. Brundle, and M. W. Robcrts, Chem. Phys. Letters, 1974, 24, 175. A. V. Sklyarov, A. G. Vlasenko, and I. I. Tret'yakov, Russ. J. Phys. Chem., 1973,47, 1622. R. L. Palmer and J. N. Smith, J. Chem. Phys., 1974, 60, 1453. J. P. Dauchot and J. van Cakenberghe, Nature Phys. Sci., 1974, 246, 61. 192 J.-M. Herrmann, P. Vergnon, and S. J. Teichner, Cornpt. rend., 1974, 278, C, 561.
218
Inorganic Chemistry of the Main- group Elements C U O , ’ V20,-M,0 ~~ (M = alkali o n the oxidation. The oxidation of CO to CO, in melts containing V,O, and alkali-metal oxides has been investigated in the temperature range 440-640 0C.194 Molten salts have the advantage over ‘solid’ catalysts in that they operate without being poisoned. The oxidizing capacity of the melts is limited only by the depletion of V,O, and the formation of the insoluble product, V204,via reaction (36). The melts may, however, be reactivated easily by treatment with oxygen.194
v,o, 4- co +
v204
co,
(36)
A mass-spectrometric investigation of the ionic species present during both the oxidation of C O and the decomposition of CO, in an r.f. discharge has been undertaken.”, A particularly interesting feature is that C+is one of the predominant ions; an analysis of the reaction mechanism suggests that it is formed in reaction (37). Cross-sections for the production of 0; and CCo++co+c++co,
(37)
by dissociative electron attachment in CO, have been measured.lY6Independent analyses of the kinetics of both CO”’ and C0,”8 dissociation behind shock waves have also been undertaken. CS, dissociation in a vitreous carbon cell has been studied using mass-spectrometric techniques;lg9CS and S are the only detected products, indicating that (38) is the dominant reaction. The temperature dependence of the concentrations of the products, however, suggests that reaction (39) is also ~ i g n i f i c a n t . ’The ~ ~ results CS,+CS+S CS, + C(wal1) + 2CS
(38)
(39)
of a mass-spectrometric study of the loss of gas-phase CS have been presented The principal loss mechanism is a heterogeneous wall reaction producing CS, and a carbon-rich wall deposit. The reaction does not appear to be accompanied by the formation of a solid CS polymer, as has been assumed previously.2o” Photoionization of C0,201and C0,-CO-0, mixturesZo2has been studied by two groups of workers. In C0,-CO mixtures, interaction of CO: ions leads to the production of (CO); and [(CO),CO,l+ cluster ions; photoionization of C0,-CO-0, mixtures, however, yields mainly oxygen-containing
’” ‘”
M. J . Fuller and M. E. Warwick, J.C.S. Chem. Cornm., 1974, 5 7 . A. Block-Bolten, B. J. M. Bertrand, and S. N . Flengas, Canad. J. Chern., 1974, 52, 2068.
L. C. Brown and A. T. Bell, J. Chern. Phys., 1974, 61, 666. D. Spence and G. J . Schulz, J. Chern. Phys., 1974, 60, 2 16. R. K. Hanson, J. Chern. Phys., 1974, 60, 4970. l Y x J . H. Kiefer, J. Chern. Phys., 1974. 61, 243. l Y y7. C . Peng, J. Phys. Chem., 1974, 78, 634. 200 R. J . Richardson, H. T. Powell. and J. D. Kelley, .1. Phys. Chem., 1973, 77,2601. K . E. McCulloch, J. Chem. Phys., 1973, 59, 4250. *‘I2 L. W. Sieck and R. Gordon, J. Res. Nut. Bur. Stand., Sect. A, 1974, 78, 315. I‘”
lY7
219 Elements of Group IV clusters. Investigation of CO-0, mixtures also revealed reactions between 0: and CO. The role of impurity reactions involving HzO is considered in detail and the implications of all data to the vapour-phase radiolysis of CO, are discussed.202A wide range of heteromolecular clusters containing CO and/or CO, together with SO,, NO, or HzO has been found in isentropically expanding jets;2o3the observed clusters and their formation conditions are summarized in Table 12. These clusters, particularly the hydrates, are of importance in atmospheric chemistry since favourable conditions for their formation are known to be present in jet-aircraft e x h a u ~ t s . ~ ~ ~ The electrochemical fluorination of COS has been carried O U ~ . " ~Cleavage of the C-S bond occurs, giving rise to COF, and SF,; small quantities of CF, and CF,OOCF, are also produced.
Table 12 Heteromolecular clusters of CO, CO,, SO,, NO, and H,O Cluster
Matrix-isolation techniques have been used to study reactions of small molecules (CO) with ionic compounds.205An analysis of the i.r. spectra of NiF,, NiC12, CaF,, CrF,, MnF,, CuF,, or ZnF, with, inter aha, C O in Ar matrices has shown that perturbations of the frequencies of both components occurs; such perturbations are thought to be indicative of interaction between the two components. The pyrolysis of C,0,206and CSZ2O7has been studied independently; that of C,O, [equation (40)] has been studied in the range 600-700°C and GO, + co+c20;
c 2 0+
co+c
(40)
20-100 rnmHg.'O6 The reaction is first-order and is strongly inhibited by NO. The reaction of C30z with NzO, however, is not inhibited by NO. Analysis of the reaction products shows the material balance (41). A 4C,O2 + NZO + N, + CO, + 7CO + 4C
(41)
reaction mechanism involving a bimolecular heterogeneous initation (42),
"'' 204
205 2oh '07
J. M. Calo, Nature, 1974, 248, 665. S. Nagase, H . Baba, K . Kodaira, and T. Abe, Bull. Chem. SOC.Japan, 1973, 46, 3435. D. A. van Leirsburg and C. W. DeKock, J . Phys. Chem., 1974, 78, 134. M.-M. Bonneau and C. Ouellet, Canad. J . Chem., 1974, 52, 167. J.-L. Destornbes and C. Marlikre, Compt. rend., 1973, 277, €3, 427.
Inorganic Chemistry of the Main - group Elements
220
followed by a small chain reaction (43)-(43, has been proposed.206
+ NZO
c 3 0 2
4
(c303) +
Nz + (c303)
(42)
coz +
(43)
c 2 0
CZO + co + c
c, -!-
c 3 0 2
-+
(44)
2c0 + Cn+l
(45)
Carbonates, Thiocarbonates, and Related Anions. Data for this section of the Report have been collected only for the simple compounds of the Main-group elements; those describing the chemistry of, for example, rare-earth metal carbonates o r transition-metal carbonato complexes have been excluded. A comprehensive single-crystal X-ray study of KHCO, and KDCO, has been carried out by Thomas et al.'"' at three different temperatures (95, 219, 298 K). The unit cells are monoclinic, space group P 2 , l a ; their dimensions are collated in Table 13. The KHCO, structure, compris-
Table 13 Unit-cell dimensions of KHC03,KDC03,and PbCO, at 298 K KHCO, KDCO, PbCO,
a/A 15.1725 15.1948 5.1800
bJA 5.6283 5.6307 8.492
CIA
3.7110 3.7 107 6.133
81"
104.63 1 104.567 -
ing (HC03):- dimers and K' cations, is isomorphous with its deuteriated counterpart. The heavy atoms of each HCO, ion within the centrosymmetric dimer are closely coplanar at all temperatures, the separation between the two planes being ca. 0.22 A; details of this aspect of the structure of the dimeric anion are given in Table 14. The molecular geometries of the two
Table 14 The planarity of the [(HCO3)J- dimer." The two parallel planes through the oxygen atoms of each HC05 ion are taken a s references ; the notation is defined a s follows: (02')
03'
Perpendicular distancestA at 298 K A
D 6
KHCO, 0.222(3) 0.09(3) 0.004(3 )
KDCO, 0.2 19(3) 0.03 (3) O.OOS(3)
Reproduced by permission from Acta Cryst., 1974, B30, 1155. ""
J. 0. Thomas, K. Tellgren, and I. Olavsson, Acta Cryst., IY74, B30, 1155. K. Sahl, Z . Krist., 1974. 139, 215.
01'
22 1
Elements of Group IV m
isotopic anions and their temperature dependences are shown in Figure 2; the two symmetry-related 0-H - - - 0 hydrogen bonds within the two dimers (HC0,):- and (DC0,):- have bond lengths 2.585 and 2.607A (at 298 K), respectively.'" The crystal structure of cerussite, PbCO,, has been refined.209It is isotypic with aragonite and crystallizes with orthorhombic symmetry, space group P, ; the unit-cell dimensions are included in Table 13. The configuration of the CO, group is discussed in relation to the structures of aragonite, strontionite, and witherite.'09 A detailed study210of the crystal structures of M,CO, (M = Li, Na, or K) between ambient temperatures and their melting points has shown that although Li,CO, has but one (monoclinic) crystalline modification, Na2C0, and K,CO, exist in three structures, with the thermal evolution: ordered monoclinic
.
-Na2COj.349 "C --K2C03,340"C
disordered monoclinic
'"'
G . Papin, Compt. rend., 1973, 277, C, 691.
479 "C
hexagonal
(46)
222
Inorganic Chemistry of the Main- group Elements
Raman studies of KHCO,"' and CaCO, (calcite)212have been carried out; the far-i.r. spectrum of KHC0,211has also been reported.'12 The vibrational have been determined by spectra of matrix-isolated CO; and COj Jacox and Milligan. The absorptions which appear near 1600 cm-' on codeposition of Ar-CO, mixtures with an alkali metal at 1 4 K have been assigned to v 3 of an M' - - CO; ion pair with an OCO valence angle near 130°.213 Stabilization of COT in an Ar matrix at 14 K has been achieved by codeposition of Ar-C02-N20 or Ar-CO-0, mixtures with The i.r. data require a CZustructure for the ion; although this deviation of the structure from the expected D,, symmetry may result in part from Jahn-Teller distortion, evidence that cation interactions play a significant role has been found. Several reactions of carbonates with oxides (both lid^^^-^^^ and gaseO U S ~have ~ ~ )been investigated. The reactivity of Na,C03 with vanadium oxides increases in the order V,O, < V,O, < V,O,, < V204;2'5 this sequence has been rationalized in terms of the vanadium oxidation state. The lowest reaction rate, however, was observed in the Na2C03-V203reaction, which is restricted by the formation of Na, 3 3 v 2 0 3 . 1 7 solid solutions. The sequential products of the reaction of BaCO, and Al,03 in the temperature range 700-1 100 "C are dependent on the reactant ratios;216the data obtained are summarized in Table 15. The kinetics of the reaction of SrCO, and WO,
Table 15 Products of the BaCO,-Al,O, BaCO, :A1,0, ratio 1:l 1:6 3: 1
reaction.'I6
Initial products BaAI,O,, CO, BaAl,O,, CO, BaAl,O,, CO,
Final products BaALO,, CO,
BaA1,z019,COz Ba,Al,O,, 3C0,
[reaction (47)I2l7and the products of the reaction of CaC03 and anorthite, CaAl,Si,O,, [reaction (48)I2l8have also been the subjects of detailed investigation. It has been established recently that CO: is stable in fused KNO, SrCO, + WO, -+ SrWO, + CO, 3CaC0, + 2CaA12Si208 + Ca,Al,Si,O,
(47)
+ Ca,Al,Si,O,, + 3c0, (48)
at 350 "C, thus clarifying previous disparate results.219Purging the melt with 21 I
G . Lucazeau and A. Novak, J . Raman Spectroscopy, 1973. 1, 573. S . A . Akhmanov, N. I . Koroteev, and A. I. Kholodnykh, J . Raman Spectroscopy, 1974, 2, 239. 'I' M. E. Jacox and D. E. Milligan, Chem. Phys. Letters, 1974, 28, 163. ' I 4 M . E Jacox and D. E. Milligan, J . Mol. Spectroscopy, 1974, 52, 363. 2 1 5 V. L. Volkov, N. Kh. Valikhanova, and A. A. Fotiev, Russ. J . Inorg. Chem., 1973, 18, 1707. ' I h J. Beretka and T. Brown, Austral. J. Chem., 1973, 26, 2527. 2 1 7 C . Flor, V. Massarotti, and R. Riccardi, Z. Naturforsch., 1974, 29a, 503. ? I x G. Hoschek, Naturwiss., 1973, 60, 548. 21u A . G. Keenen. C . G. Fernandez, and T. R. Williamson, J. Electrochem. SOC.,1974, 121, 885. 'I2
Elements of Group IV
223
oxygen or nitrogen has no effect; Cr,O?, however, will react stoicheiometrically with C0:- in the melt according to reaction (49).'l9
The reaction of variously hydrated samples of CaC03 with N204 and NOCl has been studied at temperatures up to 200°C.220The reaction schemes (50) and (51) have been confirmed for the two reactions; that of N204 with CaCO, occurs much faster than that of NOC1. It has been CaCO, + &O4
-+Ca(NO,),
+ N O +C 0 2
+ 3 N 0 + 3Coz + 3CaC1, CaCO, + zN204+ Ca(N03),+ NO + CO, 4CaC03+ 6NOC1+ Ca(NO,), + 4 N 0 + 4 c O , + 3CaC1, 3CaC0, + 6NOCl+ &O4
(5 l a ) (5 1b) (51c)
suggested that these reactions may form the basis of an analysis for mixtures of NzO4 and NOCl, the amount of chlorine present in the solid produhs being indicative of the gas-phase concentration of NOC1.220 Phase relationships in the Na2C03-CaC03-Hz0,22' KHC0,-KN0,H,0,222 NaC1-NaBr-Na,C03,223 NaBr-NaI-Na,C03,224 and NaCl-NaINa2C0:" ternary systems involving carbonates have been examined. Cyanides, Cyanates, and Derivatives of Group V Elements.-Cyanogen, Related Species. The number of papers published during the period of this Report which describe the chemistry of these species is markedly lower than that for previous Reports. Theoretical calculations of the electronic struc~ ' ~ ~been ~ * successfully tures of HCN,225HNCS,2z6and the CN r a d i ~ a l ~ have completed. The electronic structure of HNCS has been compared with that of HNCOZz6and it is concluded that (i) the .rr-system in HNCS involves a nitrogen lone pair stabilized by a C-S .rr-bond, whereas the n-system in HNCO consists of a C-0 .rr-bond stabilized by the nitrogen lone pair, and (ii) the d-orbitals of sulphur accept electron density in a u - rather than a .rr-fashion. The electronic structure of the NCS- ion has also been determined experimentally from the X-ray KB fluorescence and K absorption spectra of the S atom in KSCN.Z29 22" 221
222 221
224 225
22h
'*' ***
229
D. Bourgeois, P. Zecchini, and C. Devin, Compt. rend., 1974, 278, C, 53. E. J. Frankis and D. McKie, Nature Phys. Sci., 1974, 246, 124. P. S. Bogoyavlenskii and E. D. Gashpur, Russ. J. Inorg. Chem., 1973, 18, 1662. R. P. Lagutova, D. G . Barsegov, A. G. Yakovlev, and 1. I. Il'yasov, Russ. J . Inorg. Chem., 1973, 18, 760. I. I. Il'yasov and V. V. Volchanskaya, Russ. J. Inorg. Chem., 1973, 18, 761. G. M. Schwenzer, S. V. O'Neil, H. F. Schaefer, C. P. Baskin, and C . F. Bender, J. Chem. Phys., 1974, 60, 2787. J. M. Howell, I. Absar, and J. R. Van Wazer, J. Chem. Phys., 1973, 59, 5895. G. Das, T. Janis, and A. C. Wahl, J. Chem. Phys., 1974, 61, 1274. P. carsky, M. Machatek, and R. Zahradnik, Coll. Czech. Chem. Comm., 1973, 38, 3067. A. P. Sadovskii, L. N. Mazalov, T. I. Guzhavina, G . K. Parygina, and B. Yu. Khel'mer, J. Struct. Chern., 1973, 14, 618.
224
Inorganic Chemistry of the Main- group Elements Ab initio calculations of the molecular geometry and vibrational properties of the hydrogen-bonded complex between H CN and HF have been effected.230The complex (24) is predicted to be linear, HF being the proton
2 833 K
(23)
donor and HCN donating a lone pair to the hydrogen bond. Hydrogen bonding in mixed crystals of HCN and DCN has been studied as a function of composition using i.r. spectroscopic techniques.231 Detailed examinations of the i.r. spectra of (CN),,'32 HCN0,2333234 DCN0,234and XCNS (X = H or D)*" have been carried out; an analysis of the Raman spectra of (CN),,23"XCN (X = H o r D),"' and XCNS (X = H or D)'" has also been undertaken. Several other spectroscopic studies of (CN), (vacuum-u.v.),'38 HCN (electron energy H C P (U.P.S.),'""NH2CN (U.P.S.),24'and DCNO (mm wave)'"' have been described during the period of this Report. The phosphorus analogue of HCN, methiophosphide, HCP, has been prepared by passage of PH, through a low-intensity rotating arc struck between a pair of carbon The experimentally determined adiabatic ionization potentials of this molecule, which is unusual in that it is the only compound isolated with a P atom bonded to only one neighbouring atom, are compared with theoretically derived values in Table 16. Also included are the associated frequencies of the U.P.S. bands and the orbital assignments.
Table 16 Adiabatic ionization potentials of HCP'"' Adiabatic ionization po te n tialle V Theore tica 1 Experimental 10.0 10.79f 0.01 12.6 12.86f 0.01 20.0 -
Associated wave n urn berlcm- ' 1110f30(v,) 1250 f30(v,) -
Orbital assignment 1r-(C-P bonding) 3a-(P lone pair) 2u-(C-H bonding)
The oxidation of (CN), in (CN),-02-Ar mixtures and the distribution of the reaction products before and after ignition have been studied behind L. A. ('urtiss and J. A . Pople, J. Mol. Spectroscopy, 1973, 48, 113. H . 6 . Friedrich and P. F. Krause, J. Chem. Phys., 1973. 59, 4942. '" A. Picard, Spectrochim. Acta, 1974, 30A, 691. ''' E. L. Ferretti and K. N. Rao, .1. Mol. Spectroscopy, 1Y74, 51, 97. B. P. Winnewisser, M. Winnewisser, and F. Winther, J. Mol. Spectroscopy, 1974, 51, 6 5 2 3 5 G. R . Draper and R. L. Werner, .J. Mol. Spectroscopy, 1974, 50, 369. L.. H. Jones. J. Mo l. Spectroscopy, 1974, 49, 82. 237 J. Bendtsen and H. Cr. M. Edwards, J. Raman Spectroscopy, 1974, 2, 407. 2 3 x R. E. Connors, J. L. Roebber, and K. Weiss, J . Chem. Phys., 1974. 60, 501 1. "" W.-C. T a m and C. E. Brion, J. Electron Spectroscopy, 1974. 3, 28 1. W' D. C . Frost, S. T. Lee, a n d C. A . McDowell, Chem. Phys. Lrttrrs. 1Y73. 23, 472. H. Stafast and H. Bock, Chem. Ber., 1974, 107, 1882. M. Winnewisser and B. P. Winnewisser, Z . Naturforsch., 1974. 29a, 633. 230
"
Elements of Group IV
225
reflected shock In stoicheiometric mixtures, the major products before ignition are NZ, CO, and some COz, which disappears after ignition. In mixtures with excess oxygen, however, the products following ignition are N,, CO,, and some CO. The complex BeC12,2NCC1 has been produced by the addition of anhydrous BeC& to an excess of liquid CNCl at 0 "C, and its chemistry compared to that of the analogous BeC1,,2NCCH3 complex.244 Although BeC1,,2NCCH3 is slightly more thermally stable (d. 210 "C) than BeClZ,2NCC1(d. 120"C), they both undergo the same reaction (52) with BeC1,,2NCR
+ 2L -+BeClZ,2L+ 2RCN
(52)
R = C1 or Me; L = Et,O, MeCN, or PhCN polar solvents. A t temperatures above 0 "C, BeC12,2NCC1 acts as a catalyst in the formation of trichloro-s -triazine (CNCl), from liquid CNC1.244The formation of 1: 1 complexes of SCN- with SOz, S0Cl2, and SOzC12 has also been A u ~ t a d ' ~ ~ has * ' ~ 'published the results of a study of the reactions of CNand (XCN), (X = S or Se)'"' in anhydrous acetonitrile. He with s4062-246 postulates that the mechanism of the CN--S402interaction involves nucleophilic displacement of ionic S,O:- by CN- [reaction (53)J followed by
+ CN- + -03S-SCN + S20:-
-03s-S-S-SOY
(53)
a fast nucleophilic attack of the unstable thiocyanatosulphonate ion by CNto give ionic SCN- and the cyanosulphonate ion [reaction (54)].246 The O3S-SCN
+ CN- -+ -O-&-CN
+ SCN-
(54)
mechanism of the CN--(XCN), reaction was studied by isotope tracer techniques involving the addition of four moles of "CN- t o one mole of The two reaction mechanisms are similar; they involve fast substitution by CN- at one of the chalcogen atoms, the chalcogen dicyanide so formed reacting with CN- t o farm [X(CN),]- as shown in reaction ( 5 5 ) .
(XCN),
+
"CN-
-
XCN
+X
71
C 'N
3
~
NC\ -
~
);""
X
I
(55)
"CN
With [Se(CN),]-, the cyanide groups are labile, fast exchange occurring with the 13CN- in the solvent; the 13C:12Cratio in [Se(CN),]- is thus changed to 4:1, which is the overall 13C:12Cratio [one carbon of the (SCN), is fixed as 241 244 245
246
247
A. Lifshitz, K . Scheller, and D. Bass, J. Chern. Phys., 1974, 60, 3678. J. MacCordick, Cornpt. rend., 1974, 278, C, 1 1 77. S. Wasif and S. B. Salama, J.C.S. Dalton, 1973, 2148. T. Austad, Acta Chern. Scand. (A), 1974, 28, 693. T. Austad, Acta Chern. Scand. (A), 1974, 28, 806.
Inorganic Chemistry of the Main-group Elements 226 SCN-I. No exchange occurs with [S(CN),]-, the 13C:12Cratio being maintained at 2 : l . Both [S(CN),]- and [Se(CN),]- decompose slowly to give cyanogen and either SCN- or SeCN- [reaction (56)]; the 13C:12Cratio in the thiocyanate being 2 : 1, that in the selenocyanate is 4:l. Finally, the cyanogen rapidly adds two moles of CN- [reaction (57)].247
-
NC
(CN), + 2CN
( 57)
N
CN
Ag"', CuIII, and Nil" have been used as catalysts in the persulphate oxidation of, inter a h , KCN and KSCN.24*In the absence of the catalysts, the nitrate state is not reached in alkaline medium; the catalytic activity in attaining this stage follows the order Ag"' > CulI1> Nil". When small amounts of KSCN are added to molten NaN03-KN03 eutectic mixtures at temperatures between 230 and 316 "C, a complex and relatively violent reaction occurs.249NO;, SO:-, and basic ionic species are formed in the melt, together with NO,, C 0 2 , (CN),, N 2 0 , and minor quantities of other gaseous products. Finally, the first example of solid linkage isomers containing N- and 0 -bonded cyanate groups has been reported in the compounds Rh(PPh,),NCO and Rh(PPh,),0CN.250The i.r. spectra of the isomers have been discussed and the solvent dependence of the mode of co-ordination has been noted. 2 Silicon, Germanium, Tin, and Lead reactions of Hydrides of Silicon, Germanium, and Tin.-Ion-molecule silane mixtures studied by mass-spectrome tric methods have continued to provoke attention. Protonation of SiH, by proton transfer from CH; or NH: affords the silanium ion SiH:. Chemical non-equivalence of the hydrogens in SiH: has been deduced from the exclusive formation of HD from the reaction of SiD,H' with ammonia, leading to the preference of structures with symmetries lower than the D,, trigonal-bipyramidal Ion-molecule reactions in monosilane that represent a net hydride-ion transfer proceed via a direct, stripping-type process, yielding an ion with very low kinetic energy, and by a complex-formation mechanism leading to a scrambling of H and D atoms.252The principal reaction in monosilane-water mixtures is one of hydride-ion transfer from monosilane
'" 24')
-,511
"'
'''
P. K . Jaiswal and K. L. Yadava, Indian J. Chew.. 1973, 11, 5Y8. M. E. Martins, A . J . Calandra, and A . J . Arvia, J . Inorg. Nucleur Chem.. lY74, 36, 1705. S. J . Anderson, A . 11. Norbury, and J . Songstad, J.C.S. Chem. Cornrn., 1974. 37. M . D. Sefcik, J . M. S. Henis, and P. P. Gaspar, J. Chew. Phys., 1974, 61, 4320. T. M . Mayer and F. W. Larnpe, J . Phys. Chem., 1974. 78, 2195.
Elements of Group IV 227 to ions derived from The reactions of primary ions formed from methane with monosilane and of primary ions formed from monosilane with methane have been studied using monosilane-methane mixtures. All primary ions of each constituent undergo at least one ion-molecule reaction with the opposite molecule, but by far the most predominant such cross-reaction is again hydride transfer from monosilane to primary ions of methane, producing the SiH: Ion-molecule reactions in disilane have been studied by similar techniques. All primary ions react with the parent molecule, resulting in a polymerization to higher silicon hydride~."~ Model calculations 01 the displacement reaction of H atoms with disilane have suggested that the reaction proceeds via a bridged activated complex rather than a linear Structural parameters for GeH,X, (X = Cl or Br)257and also for Me,SnH and Me2SnHZz5* have been determined by electron diffraction. All four molecules are tetrahedral in the gas phase, with principal bond distances as follows: GeH,Cl, r(Ge-C1) = 2.130(3), r(Ge-H) = 1.56(2); GeH,Br, r(Ge-Br) = 2.277(3), r(Ge-H) = 1.52(4); Me,SnH r(Sn-C) = 2.147(4), r(Sn-H) = 1.705(67); Me,SnH, r(Sn-C) = 2.150(3) r(Sn-H) = 1.680(15)A. Structural data (ratios of interatomic distances and bond angles) have been calculated from 'H and 'H n.m.r. spectra for CD3SiH3, CH3SiD3,CD,GeH,, and CH,GeD3 dissolved under pressure in the nematic phase of p-ethoxybenzylidene-g -n-butylaniline. The data obtained are in good agreement with those deduced from microwave and other The heights of the barriers to internal rotation in CF,GeH,26" and CHzFGeH,26'have been measured to be 1280 f 150 cal mol-' and 1390 f 40 cal mol-', respectively, from microwave data, whilst the barriers to rotation in CH3SiH32"2*2"3 and disilane'"' have been the subject of theoretical calculadisilane,'", organosilanes and tions. The dipole moments of CH3SiH3,263vz64 halogeno-organosilanes,265 and CH3GeH3and H,GeX (X = C1, Br, or I)'" have been determined. Stannic bromide has been used as a selective brominating agent for silanes. Monosilane, disilane, and the methylsilanes Me,SiH,-, (n = 1-3) all react to convert one Si-H bond into a Si-Br bond with no trace of
"' T. M.
H. Cheng and F. W. Lampe, J. Phys. Chem., 1973, 77, 2841. T. M. H. Cheng, T. Y . Yu, and F. W. Lampe, J. Phys. Chem., 1973, 77, 2587. 25s T. M. H. Cheng, T. Y. Yu, and F. W. Lampe, J. Phys. Chem., 1974, 78, 1184. 256 I. Safarik, T. L. Pollock, and 0. P. Strausz, J. Phys. Chem., 1974, 78, 353. 257 B. Beagley, D. P. Brown, and J. M . Freeman, J. Mol. Structure, 1973, 18, 335. 25R B. Beagley, K. McAloon, and J. M. Freeman, Acta Cryst., 1974, B30, 444. 2 5 9 R. Ader and A. Loewenstein, J. Amer. Chem. SOC., 1974, 96, 5336. "'L. C. Krisher, W. A. Watson, and J. A. Morrison, J. Chem. Phys., 1974, 61, 3429. 26 I L. C. Krisher, W. A. Watson, and J. A. Morrison, J. Chem. Phys., 1974, 60, 3417. ''' C. S. Ewig, W. E. Palke, and B. Kirtman, J. Chem. Phys., 1974, 60, 2749. 26' M. S. Gordon and L. Neubauer, J. Amer. Chem. Soc., 1974, 96, 8690. 264 J. M. Bellama, R. S. Evans, and J. E. Huheey, J. Amer. Chem. Soc., 1973, 95, 7242. 2 6 5 A. N. Egorochkin, N . S. Vyazankin, and M. G. Voronkov, Doklady Akad. Nauk S.S.S.R., 1973, 211, 616. "' J. M. Bellama, S. 0 . Wandiga, and A. A. Maryott, J.C.S. Faraday 11, 1974, 70, 719. 254
228
Inorganic Chemistry of the Main-group Elements
dibr~mination.~ Trichlorosilane '~ selectively reduces the phosphonyl group of S,1O-dihydro-S-phenyldibenzo[b,e]phosphorin-lO-one 5-oxide to the corresponding ketophosphine in 90% yield.268U.V. irradiation of gaseous mixtures of trifluoro- or trichloro-silane with trifluoronitrosomethane results in the formation of the 0-(trihalogenosily1)-N-(trifluoromethy1)hydroxylamine in small yield .269 Hydrosilylation of carbon-carbon multiple bonds and other similar systems has been the subject of several investigations, mechanistic aspects of catalytic processes being particularly studied. The addition of trichlorosilane to the C=C bonds of model polyalkadienes takes place in the presence of hexachloroplatinic acid under pressure and at high temperature, the reaction rate depending on the nature of the double bond involved."" The photochemical addition of trichlorosilane with fluorinated olefins gives different amount of products depending on the concentration of the reactants. With excess trichlorosilane the major product of reaction with 2chloro-1,1-difluoroethylene is trichloro-(2,2-difluoroethyl)silane together with smaller amounts of trichloro-( 1,1-difluoroethyl)silane. The same reaction with excess of olefin gives mainly trichloro-(2-chloro-2,2-difluoroethy1)silane accompanied by trichloro-(2-chloro-1,1-difluoroethyl)silane. The formation of these products may be rationalized by initial trichlorosilyl radical addition to 2-chloro-l,l-difluoroethyleneat the CF, group and a competing reduction of the olefin to 1,l-difluoroethylene followed by trichlorosilyl radical addition at the CH, group. Photochemical reaction of trichlorosilane with 2-bromo-1,l -difluoroethylene gives the reduction product 1,1-difluoroethylene and 2,2-difluoroethyl- and 2-bromo-2,2-difluoroethyl-trichl~rosilanes.~~~ The kinetics of the addition of trichlorosilane to acetylene at 100 "C catalysed by polymer-supported chloroplatinic acid have been studied and correlated by equations derived for heterogeneously catalysed reactions. The addition of the product, vinyltrichlorosilane, to the initial reactants had a rate-enhancing effect.272The stereochemistry of the addition of dichlorosilane to acetylenes has also been studied in the presence of chloroplatinic acid, platinum on carbon, and benzoyl peroxide as catalysts. Platinum-catalysed additions proceed in a stereospecific cis manner, giving trans -adducts, whereas peroxide-catalysed additions gave predominantly cis -adducts except for 3,3 -dimethylbut- 1-yne, which gave largely the trans Stereospecific trans addition of triorganosilanes to acetylenes is also achieved by the use of tris(tripheny1phosphine)rhodium
N. S. Hosmane, Inorg. Nucleur Chem. Letters, 1974, 10, 1077. Y. Segall, I. Granoth, and A. Kalir. J.C.S. Chem. Cornrn., 1974, 501. "' A. A. Kirpichnikova, V. G . Noskov, M . A . Sokal'skii, and M. A . Englin, J . Gen. Chern. ( U . S . S . R . ) , 1973, 43, 1852. 270 C . Pinazzi, J . C. Soutif, and J . C. Brosse, Buli. S O C . chirn. France, 1974, 2166. 271 W. 1. Bevan, R. N . Haszeldine, J . Middleton, and A. E. Tipping, J.C.S. Dalton, 1974, 230.5. 2 7 2 M. Kraus, Coll. Czech. Chern. Cornrn., 1974, 39, 1318. 2 7 3 R . A . Benkeser and 0. F. Ehler, J. Organornetullic Chem., 1974, 69, 193. 2h7 268
Elements of Group IV 229 chloride as catalyst.274Ziegler-Natta catalyst systems of the types M(acac),AlEt, ( M = N i , Co, or Fe) catalyse the hydrosilylation of 1,3-dienes or terminal acetylenes. Nickel salts provide the best catalysts, and a mechanism which involves the successive formation of a NiO complex, its oxidative adduct L(diene)Ni(H)SiX,, a n-ally1 complex L(n-allyl)NiSiX,, isomeric n-pentenyl derivatives, and finally the hydrosilylation product and the regenerated NiO complex is proposed .275 Hydrosilylation has also been used for the synthesis of silicon heterocyclic compounds. Ring formation from the unsaturated silanes CH,=CH(CH,), SiMe2H (n = 0-6) depends upon the value of n. No ring closure takes place when n = 0 or 1, but cyclic products were obtained when r~ = 2.276Palladium chloride or tris(tripheny1phosphine)rhodium chloride catalyse the addition of triorganosilanes to carbodi-imides to form N-silylformamidines in high yield.”’ Catalytic hydrosilylation using rhodium(1) complexes with optically active phosphine ligands has been employed to achieve asymmetric reduction of The photolysis of H,S in the presence of Me,SiD, leads to the formation of large yields of D,. This apparent exchange reaction is, however, due to a photochain sequence involving the intermediates Me,Si(D)SH and Me2Si(D)S.279Kinetic studies of the ozonolysis of silanes have supported previously proposed mechanisms. The first step involves co-ordination of ozone to silicon followed by electrophilic attack at the Si-H bond.,’’ Product analysis of the flow pyrolysis of Me,GeH is consistent with a decomposition involving Me,Ge’, H , and Me’ radicals. The pyrolysis of Me,SiH is much more complex, presumably due to the formation of silicon-carbon double-bonded intermediates and the Me,Si(H)CH, radical
Silicon Solid-state Chemistry.-Contrary to the pattern adopted in previous volumes, the chemistry of aluminosilicates and zeolites will not be discussed here; the data published during the period of this Report associated with these materials are considered in detail in Chapter 3. In this section, silicon dioxide and the silicates will be described separately; emphasis will be laid on the inorganic chemistry of these compounds, and papers describing solely their catalytic, adsorption, diffusion, and other similar properties will not be considered. Silicon Dioxide. Although most authors in this field are interested in the chemistry of species adsorbed o n the surface of Si02, a limited number of papers have been published describing the physical and chemical properties I . Ojima, M. Kumagai, and Y. Nagai, J. Organometallic Chem.. 1974, 66, C14. T. A. Nile, and S. Takahashi, J. Organometallic Chem.. 1974, 72, 425. ”’ J. V. Swisher and H. H. Chen., J. Organometallic Chrm., 1974, 69, 83. 277 I. Ojima, S. I . Inaba, and Y. Nagai, J. Organometalk Chem., 1974, 72, C11. ’’’ 1. Ojima and Y. Nagai, Chem. Letters, 1974, 223. A. G . Alexander, R. W. Fair, and 0. P. Strausz, J. Phys. Chem., 1974, 78, 203. ’*(’ Yu. A. Aleksandrov and B. I . Tarunin, Doklady Akad. Nauk S . S . S . R . , 1973, 212, 789. D.P. Paquin. R. J . O’Connor, and M. A. Ring, J . Organometallic Chem., 1974, 80, 341. 274
’’’ M . F. Lappert,
’’’ ”’
230
Inorganic Chemistry of the Main- group Elements
of the pure material. Three theoretical investigations of SiO, have been ~ n d e r t a k e n ; ~the ~ ~ co-ordination -~~~ in, and the i.r.283 and Raman283,284 intensities of, single crystals of a - and p-quartz have been calculated. Satisfactory agreement is observed with the experimental spectral data.283,284 An irradiation-induced phase transition of the same kind as the a+ transition has been found in quartz;”’ it occurs at a dose rate of 4-5 X lo’” fast neutrons cmp2. A single-crystal study of the cristobalite inversion has also been carried out.286 Instrumental parameters for the determination of the 0 : S i ratio in SiO, films using Auger electron spectroscopy have been studied and o p t i m i ~ e d . ~ ~ ’ The ratio of the Auger peak heights for the two components is a measure of their relative abundance and can yield meaningful results, when compared with a standard. X-Ray absorption spectra of SiO,, SiO, and Si in the Si K edge region have been The structure of the high-energy absorption edge is strongly influenced by the type of bonding, showing that SiO cannot be a mixture of Si and SiO,. This conclusion confirms that derived from optical measurements and is consistent with the hypothesis that several tetrahedral arrangements different from those associated with Si and SiO, are present in SiO.”’ The nature of the impurity water in synthetic quartzzxyand of the 0- hole centre in natural quartz”” has been examined by i.r. and e.s.r. spectroscopic techniques, respectively. The reaction between SiO, and A1 has been studied as a function of both temperature and SiO, ~rystallinity.~”~ The reaction products formed between 850°C and’ the melting point of A1 are 8-A1,0, and Si. The activation energy of the reaction is dependent on the type of SO,, varying from 31 f 3 kcal mol-’ for vitreous silica to 64*6 kcal mol-’ for quartz; it decreases abruptly at the melting point of Al, and a volatile oxide (probably A1,O) is formed.’”’ F r i e ~ e r has ~ ” ~shown that hydrophobic, hydrophilic, and organophilic SiO, surfaces may be distinguished easily by two independent contact-angle measurements with different liquids. Interest in SiO, surface chemistry has centered, however, on the characterization (principally by means of i.r. and e.s.r. spectroscopy) of the functional groups present on surfaces subjected to ”* *”
V. N. Pak, Russ. J. Phys. Chem.. 1973. 47, 1332. J . Etchepare, M. Merian, and L. Smetankine, J. Chem. Phys.. 1974. 60, 1873.. 284 J. Etchepare a n d M. Merian, Compt. rend., 1974, 278, B, 1071. 2 8 5 E. V . Kolontsbva, E. E. Kulago. and N. A . Toniilin, Souiet Phys. Cryst., 1973, 18, 752. ’“ D. R. Peacor, Z. Krist., 1973, 138, 274. ”’ J . N. Smith, S. Thomas, and K. Ritchie, J. Electrochem. Soc., 1974, 121, 827. *’’ C. Senemaud, M. T. Costa Lima, J . A . Roger, and A. Cachard, Chem. Phys. Letters, 1973,26, 431. ”’ L. I. Tsinober and V. E. Khadzhi, Soviet Phys. Cryst., 1974, 18, 699. ”” M. I. Samoilovich, A . 1. Novozhilov. L. I. Tsinober. and A. G. Malyshev, J. Struct. C‘hem., 3973, 14, 416. ”’ K . Prabriputaloong and M. R. Piggott, J. Electrochem. Soc.. 1973, 121, 430. 2 y 2 R. G. Frieser. J. Electrochem. Soc.. 1974, 121, 669.
23 1 Elements of Group IV various adsorbates. Kondo et al.293 have studied the thermal behaviour of silanol groups on silica gel by i.r. spectroscopy. The broad OH stretching vibrations have been curve-resolved into the component bands as a function of temperature. The spectra became progressively simpler (and composed of fewer component bands) as the temperature was increased (Figure 3). An assignment of the six component bands has been attempted;
Figure 3 OH-stretching absorption bands and their component bands of silanol in various heat-treatment temperatures. a, b, c , d, e, and f show the maximum wavenumbers of the component bands at 3870, 3750, 3630, 3470, 3260, and 3030 cm-I, respectively (Reproduced by permission from Bull. Chem. SOC.Japan, 1974, 47, 553) those at 3030 and 3750 cm-' were assigned to' adsorbed water and free O H groups, respectively, whereas those at 3260, 3470, and 3630cm-' were assigned to hydrogen-bonded OH groups. That at 3870cm-' was not assigned.2931.r. studies of the adsorption of CH,D3-,0H ( 0 s n d 3),'" GH,0H,295t-C,H,OH,*" and various other have been undertaken. Force-constant calculations294utilizing only the CH and CD stretching modes have been used to show that the strongest spectral features of the CH,D3-"OH adsorbed species can be assigned to an unsymmetrical surface SiOMe group with one strong and two weak CH bonds. Some additional spectral features, which grow reversibly in intensity with increasing sample temperature, have been assigned to a symmetrical SiOMe species.294Clusters of C,H,OH and t-C,H,OH were found to adsorb via hydrogen bonding to the SiO, the results obtained have been compared with those of the adsorption of C,H,OH on AlzO,, and the different behaviour of the 2q3 2y4 z95
29h
S. Kondo, M. Muroya, and K. Fujii, Bull. Chem. SOC. Japan. 1974, 47, 553. B. A. Morrow, J.C.S. Faraday I , 1974, 70, 1527. H. Jeziorowski, H. Knijzinger, W. Meye, and H. D. Muller, J.C.S. Faraday I, 1973, 69, 1744. R. G. Azrak and C. L. Angell, J. Phys. Chem., 1973, 77, 3048.
232
Inorganic Chemistry of the Main- group Elements two oxides has been discussed in terms of the different metal-oxygen bond character. Meyer and Basti~k'~'conclude from the results of a number of experiments that H,S is adsorbed on to a silica surface according to a double mechanism: ( a ) by formation of S - - H-0 hydrogen bridges with the surface OH groups, and ( b ) by formation of surface aggregates as a result of S . H-S hydrogen bonding in the adsorbed phase. Glass and Waring,2's however, have interpreted the adsorption isotherms of H2S, CH,SH, C2H5SH, and MezS solely in terms of an adsorbed species involving S - - - H-0 hydrogen bonds between the surface OH and the S atoms of the adsorbate.''* An i.r. study of the reactions between C,H,NCO and SiO, surfaces has been undertaken.2y' 'The products of the adsorption process include a surface urethane, 1,3-diethylurea, a biuret, dissociatively adsorbed isocyanate and ethoxy-groups, and compounds formed by the polymerization of isocyanic acid and HCN. NO3""and the radicals formed by photolysis of CH,IZ3" and CH,OH"* have been studied when adsorbed on SiO, surfaces by e.s.r. techniques. At least two adsorption sites were found for NO;300one is present o n gels pretreated at low temperatures (. E. Ledina, V. V. Sulima, A . M. Krapivin, V. N . Perchenko, and N. S. Nametkin, Doklady Chem., 1973, 212, 718. I. Matsuda, K . Itoh, and Y . Ishii, J. Organometallic Chem., 1974, 69, 3 5 3 . D. A. Armitage and A. W. Sinden, J. Inorg. Nuclear Chem., 1974, 36, 993.
268
Inorganic Chemistry of the Main -group Elements
bonds of the The bis(trimethylsi1yl)sulphodi-imide Me3SiN=S=N-SiMe, undergoes Si-N bond cleavage o n reaction with chlorine, giving Me3Si-N=S=N-CI. Similar reactions with CF,COCl and SC1, afford CF,CO(S,N,) and S(NSN-SiMe,),, respectively. This latter compound reacts further with SCl,, giving S4N4.Tris(trimethylsily1arnino)sulphur (Me,SiN),S may be obtained by the reaction of Me,SiNSOF, with NaN(SiMe,),.”’ Silylated bisiminophosphoranes of the type Ph,P(=NSiMe,)(C‘H2),Ph,P(=NSiMe,) ( n = 1, 2. or 3) and the similar cyclic compound (26) have been obtained from the reaction of the appropriate
silyl azide and alkylene-biphosphines. The open-chain compounds are desilylated by ethereal HCI, and undergo condensation reactions, as does the cyclic compound with fluorophosphoranes Ph,PFr n, with the elimination of fluorosilane and the formation of partially fluorinated ionic diphosphaza-phosphonium ring systern~.’~“ Wiberg has investigated the reactions of bis-silylated di-imines in detail. The thermolysis is complex, and several modes of decomposition have been elucidated. Observed pathways include disproportionation to nitrogen and tetrakis(trimethylsily1)hydrazineand also to nitrogen and tris(trimethylsilyl)hydrazine, by dimerization to tetrakis(trimethylsilyl)tetrazene, and by cleavage to nitrogen and tris(trimethylsily1)amine and also to nitrogen and bis(trimethylsily1)amine. Decomposition to hexamethyldisilane and nitrogen is not observed.575The thermolysis is free-radical in nature, and one of the radical intermediates involved is the tris(trimethylsily1)hydrazyl radical, which can react with hydrogen-donor solvents to generate radicals R which can lead to the formation of other reaction products. Thus with toluene, in addition to the five main products, tris- and bis-(trimethylsi1yl)benzylhydrazine and bis(trimethylsi1yl)benzalhydrazone are produced.576Further deuteriation studies showed that, of the five main products, two, part of tetrakis(trimethylsi1yl)hydrazine and all of tetrakis(trimethylsilyl)tetrazene, are directly formed from two molecules of bis(trimethylsi1yl)di-imine by disproportionation and dimerization, respectively. The other products arise from radical chain reactions.537The reaction of bis(trimethylsi1yl)di-imine with a1kali metals in diethyl ether results in Br- >> NO;.691The competition between chloride, bromide, and sulphate for Pb" in glass systems has also been studied. With chloride and bromide present, mixed co-ordination spheres occur, but with sulphate present Pb2+tolerates mixed co-ordination spheres much less r e a d i l ~ . " ~
Oxygen Derivatives. The low-temperature form of tin(11) tungstate SnWO, is stable below 940°C. It is dark red, diamagnetic, and semiconducting, and the structure in the crystal may be considered as consisting of sheets of (W0,)'- polyanions separated by Sn" cations. Both "" 688
689 69 1
'''
R. Prasad and 0. N . Srivastava, Actu C'ryst., 1974, B30, 1748. H. J . Haupt, F. Huber, and H. Preut, Z. unorg. Chem., 1974, 408, 2 0 9 A. Galinos and I. Triantafillopouiou, Monatsh., 1973, 104, 1534. M. Binnewies and H. Schiifer, Z . anorg. Chem., 1974, 410, 149. J. A. Duffy and M. D. Ingram, J . Inorg. Nuclear Chem., 1974, 36, 39. J . A. Duffy and M. D. Ingram, J . Inorg. Nuclear Chem., 1974, 36, 43.
Elements of Group IV
299
metals have distorted octahedral co-ordination, with Sn-0 bond distances ranging from 2.18 to 2.83A.693A series of pyrochlore compounds of Pb(Ti,,Snl-,)03 have been prepared in aqueous media, and have inhomogeneously distributed Ti and Sn ions in equivalent lattice positions. The thermal transition from the pyrochlore-type Pb(Ti0.4-Sn0.6)03 to the perovskite-type system occurs preferentially at Ti-rich micro-regions in the matrix lattice, in which a measurable fluctuation of the Sn:Ti ratio can be dete~ted.~'" The solubility limits and the symmetry of solid solutions in complex lead oxide systems with the perovskite structure have been determined.69sThe crystal structures of lead trititanate PbTi;O, and lead metavanadate PbV206 have been determined. PbTi,07 crystals contain Ti06 octahedra which are connected to each other by corner- and edge-sharing to form a three-dimensional network of the composition Ti,O,. The lead atom is surrounded by seven oxygen atoms, with Pb-0 distances of PbV,O, has two distinct vanadium atoms, each between 2.36 and 3.04 A.696 co-ordinated to five oxygen atoms. The distorted V 0 6 octahedra are completed by a sixth much longer V-0 bond. The lead ion is co-ordinated to nine oxygen atoms lying in a spherical shell with inner and outer radii of 2.56 and 2.90 A.."" The binary compounds PbO.,WO3, 2Pb0,W03, 4Pb0,Bz03, 2Pb0,Bz03, 5Pb0,4B,03, and Pb0,2B20, and the ternary compound 15Pb0,3Bz0,,2W0, have been characterized in the ternary system PbO-B20,-W0,.698 The binary phases 2PbO,WO, and P b 0 , W 0 3 have also been shown to occur in the PbO-V,O,-WO, system, together with the phases 3Pb0,V,0s and 2Pb0,V205.699 The reaction between Nb20s, TiOZ, and PbO at 1000 "C produces a non-stoicheiometric phase, Pb2-, (Nb,Ti),O,+, of the pyrochlore type.700 Three phases occur in solid solutions PbZr,-,(Fel,2Nb1/2),03.701 Crystals of [Pb4(OH)4],(C03)(C104)lo,6H20702 and [Pb4(OH)4](C104)4,2H20703 both contain discrete [Pb4(0H),]"+ ions in which the lead atoms occupy the corners of a slightly distorted tetrahedron and the hydroxide groups are located outside the faces of the tetrahedron. Several papers report studies about p -keto-enolato and related derivatives of bivalent tin and lead. These compounds have been prepared by the reaction of either bis(methylcyclopentadienyl)tin, tin dimethoxide, or lead monoxide with the appropriate protic reagent or from tin(rr) chloride and 693
W. Jeitschko and A. W. Sleight, Acta Cryst., 1974, B30, 1088. K. Takahashi, Bull. Chem. Soc. Japan, 1974, 47, 1568. '')< E. G. Fesenko, M . F. Kupriyanov, R. U . Devlikanova, and V. S. Filip'ev, Soviet Phys. Cryst., 1974, 19, 67. hY6 K. Kato, 1. Kawada, and K. Murarnatsu, Acta Cryst., 1974, 830, 1634. 6y7 B. D. Jordan and C. Calvo, Canad. J. Chem., 1974, 52, 2701. 698 V. T. Mal'tsev, A. G. Bergman, P. M. Chobanyan, and V. L. Volkov, Russ. J. Inorg. Chem., 1973, 18, 1764. 699 V. T. Mal'tsev, V. L. Volkov, and T. V. Morgulis. R U S SJ. . Inorg. Chem., 1973, 18, 1786. 700 J. Bachelier, M. Hervieu, and E. Quemeneur, Bull. SOC.chim. France, 1973, 2503. 701 A. Marbeuf, J. Ravez, and G. Demazeau, Rev. Chim. minirule, 1974, 11, 198. '02 S. H. Hong and A. O h , Acta Chem. Scand., 1973, 27, 2309. 703 S. H. Hong and A. O h , Acta Chem. Scand., 1974, 28, 2 3 3 .
"' S. Shirasaki, H. Yarnarnura, K. Murarnatsu, and
300 Inorganic Chemistry of the Main-group Elements the sodium ~ a 1 t . ~ The ~ ) ~ tin(i1) - ~ ~ ~bis(P -keto-enolates) undergo facile oxi&mve-addition reactions, forming dihalogenobis(P -keto-enolato)tin(xv) derivatives on reaction with chlorine or br~mine,'~'and monoalkyltin(1v) halide bis(P -keto-enolates) with alkyl halide^.'^"^''"^^"^ Tin(1r) dimethoxide and bis(acety1acetone) react similarly with diphenyl disulphide to afford X,Sn(SPh), (X = OMe or acac) compounds, which disproportionate to XSn(SPh), and X,SnPh. The reactions with diethyl acetylenedicarboxylate and diethyl azodicarboxylate yield oligomeric addition products of the types [(EtO,C)E-E(CO,Et)Snx,l, (E-E = C=C or N-N), where n has values of six, nine, and higher.70s Lead(r1) bis(hexafluoroacety1acetonate) forms complexes with 1,lO-phenanthroline, 2,2'-bipyridyl, and NNN'N'-tetramethylethylenediamine, and the ionic complex species [Pb(hfac),I2(hfac = hexafluoroacetylacetone) with tmndH' hfac- [tmnd = 1,8-bis(dimethylamino)naphthalene]."" The crystal structure of the mixed-valence tin carboxylate Sn1'Sn'"(0,CC6H,N02-o),0,THF has been determined, and it contains octahedrally co-ordinated tin(rv) atoms and pentagonal-pyramidal tin( 11) atoms. The carboxylate groups bridge the tin(rr) atoms to adjacent tin(rv) atoms, and the oxygen atom not only bridges neighbouring tin(rv) atoms, forming a distannoxane ring, but also co-ordinates to a tin(r1) atom via the axial site of the pentagonal pyramid. The equatorial positions of the pyramid are occupied by oxygen atoms from four bridging carboxylate groups and the molecule of THF of ~olvation.'~~' A detailed study of the Mossbauer parameters of Sn,(edta),2H20 has been carried out over the temperature range 78 d T G 226 K, and the two different metal sites known to be present from the X-ray diffraction study have been identified. Comparison of the data with the complexes MSn(edta) (M = Ca, Ba, Sr, Mg, Co, Mn, or 2Na) have shown that one tin is covalently bound by the chelating edta, whilst the other is present as the gegenion bound by appreciably ionic interactions. The variable-temperature data confirm the absence of phase transitions or structural discontinuities between 78 K and room temperat ~ r e . ~ Lead(1r) ll succinate exhibits a phase transition from tetragonal to cubic at 160 "C, with AH = 0.6 kcal mol-' and AS = 1.4 kcal rn~l-'.''~ The crystal structure of u-penicillaminatolead(I1) shows that the amino-acid functions as a terdentate ligand towards lead(II), forming three strong interactions, with r(Pb-0) = 2.444, r(Sn-N) = 2.444, and r(Pb-S) 2.716 A.In addition, two weaker Pb-S interactions (3.160, 3.480 A) and 711-3
P. F. R. Ewings. D. E. Fenton, and P. G . H a r r i w n , lnorg. Ntccleur ('hrtn. Lrrters. I 74. 10, 43. 5I'' S. Gopinathan. C . Gopinathan, a n d J. Gupta, Indiun J. Chem.. 197.3. 11, 1067. 71'h C. Gopinathan a n d S. K. Pandit, Indian .I. Chem.. IY7.3, 11, IOW. 7117 I . Wakeshima and I. Kijima. J. Orgunometallic Chem., 1974 7 6 , 37. 711x K. D. Bos, E. J . Bulten, and J . G. Noltes, .J. Orgunometallic C'hem.. 1974. 67, C13. 7114 D. E. Fenton a n d R. Newman. J.C'.S. Dalton, 1974. 655. 710 1'. F. R . Ewings, P. Ci. Harrison, T. J . King, and A. Morris. J.('.S. Chem. Cornm., 1974, 53. "I A. J. Rein. J. L. K. F. De Vries, and R. 14. Herber. J. InorK. Nuclear C'hem., 1974, 36, 8 2 5 . 'I2 K. Nagase and H. Yokobayashi, Chem. Letters, 1974,861.
Elements of Group IV
30 1
one Pb-0 interaction (2.768A) link adjacent lead atoms, resulting in distorted pseudo-pentagonal-pyramidal co-ordination at lead(Ir), with the stereochemically active lone pair occupying an equatorial site (Figure 36).'13 The complexation behaviour of lead(I1) with anions derived from glutamic, ethylenediamine-NN'-diaceti~,~~" ethylenediamine-NN'-dimalonic, -disuccinic, and -diglutaric,' l5 ethylenediaminete tra-ace tic, N-(2-hydroxye thy1)-
Figure 36 The structure of D-penicillaminatolead (11) (Reproduced from J.C.S. Chern. Cornrn., 1974, 366)
ethylenediamine-NN'N'-triacetic, 2,2'-ethylenedioxydi(ethylamine)NNN'N'-te tra-acetic, diethy lenetriaminepenta-acetic, N-( 2 -hydroxye thy1)iminod i a ~ e t i c ,and ~ ~ ~valeric and isovaleric and asparagine, aspartine, cysteine, glutamine, his tidine, phenylalanine, serine, tryp t ~ p h a nl 8, ~ pyridoxine,"' and dopamine, adrenaline, noradrenaline, and tyramine720 have been studied. Complexation between lead(I1) formate, acetate, propionate, butyrate, valerate, and caproate with piperidine, and also between lead(I1) perchlorate and substituted thioureas, has been Hydrated sodium hypophosphite in methanol rapidly reduces germanium(1v) chloride to Ge"(HP0,). The addition of a large cation such as NMe,H', Rb', or Cs' to the reaction mixture results in the formation of the complex species M'[Ge(HPO3)C1]-. Whereas no significant reaction occurs between Ge(HP0,) and HBr, HCI, HF, H,SO,, or HN03, concentrated HI 713
H. C. Freeman, G. N . Stevens, and I. F. Taylor, J.C.S. Chem. Comm., 1974, 366. M. Kodama, Bull. Chem. Soc. Japan, 1974, 47, 1547. '" I. P. Gorelov, A. P. Samsonov, and M. K. Kolosova, Russ.J. Inorg. Chem., 1973, 18,934. 7 1 h M. Kodama, K. Namekawa, and T. Horiuchi, Bull. Chem. Soc. Japan, 1974, 47, 2011. 'I4
717 'IH
719
72 I 722
K. K. Choudhary, D. S. Jain, and J. N. G a u r , Indian J. Chem., 1974, 12, 655. A. M. Corrie, M. L. D. Touche, and D. R. Williams, J.C.S. Dalton, 1973, 2561. D. N . Chaturvedi and C. M. Gupta, J . Inorg. Nuclear Chem., 1974, 36, 2155. B. Grgas-KuZnar, V. Simeon, and 0. A. Weber, J. Inorg. Nuclear Chem., 1974, 36, 2151. R. I. Kharitonova and S. S. Sydykova, Russ. J. Inorg. Chem., 1973, 47, 504. V. A. Fedorov, A. V. Fedorova, G. G. Nifant'eva, L. G. Soboleva, and L. I. Gruber, Russ.J. Inorg. Chem., 1973, 18, 1778.
Inorganic Chemistry of the Main -group Elements
302
-1
3 3
I
Figure 37 The co-ordination of the lead atom in cerussite, PbCO, (Reproduced by permission from Z . Krist., 1974, 139, 215) converts the compound into Ge12.727Tin(1i) monofluorophosphate has a structure consisting of sheets of PO,F anions with tin(ri) ions lying midway between the anion layers. Each tin(I1) ion has six oxygen and two fluorine neighbours. Three of the oxygens are a t short distances (mean 2.15 A), the other three being a t an average distance of 3.13 A from the tin. T h e two fluorine atoms are a t an average distance of 3.49A from the tin.72JIn cerussite, PbC03, the lead(I1) atoms are in nine-fold co-ordination, with one oxygen at 2.62 A, and two each at 2.66, 2.68, 2.7 1 , and 2.77 A (Figure 37).725T h e reaction of tin([]) chloride and methanesulphonic acid produces 723 724 725
P. S. PobkoLim and C . P. Ciucngerich. I t i o r g . C'hetti.. 1974. 13, 241 A . F. Berndt, Acta Cryst.. I Y 7 4 . B30, 529, K . Sahl, Z . Krist.. 1974. 139, 215.
Elements of Group IV
303
tin(rr) methanesulphonate, which forms adducts with pyridine and butylamine. Freezing-point studies in the Cs0,SMe-Sn(O,SMe), system M’ and M3’ species indicate the presence of the phase CS,S~(O,SM~),.’*~ (M =Sn or Pb) have been detected in the e.s.r. spectra of 6oCoy-irradiated tin and lead The e.s.r. spectra of irradiated lead(I1) nitrate provide evidence for electron transfer to and from lead(r1) Sulphur Derivatives. The crystal structures of a number of lead sulphide minerals have been determined. PbGeS, consists of GeS, tetrahedra linked to form infinite [(GeS,),]’”- chains, with two tetrahedra’per identity period. The co-ordination sphere of the lead(I1) atoms is occupied by five sulphur atoms at distances of between 2.736 and 3.016A in a distorted squarepyramidal arrangement, with the lone pair occupying the sixth octahedral The structure of freieslebenite, PbAgSbS,, is a superstructure of a PbS-type substructure. Lead is co-ordinated by six sulphur atoms in a distorted octahedral arrangement, with Pb-S distances ranging from 2.806 to 3.167A.732Cosalite, Pb2Bi,Ss, has two lead atoms in the unit cell that have distorted octahedral co-ordination and two which are eight-coordinated with sulphur atoms at the apices of a trigonal prism and two additional sulphur atoms. The Pb-S distances fall in the range 2.723.47 A.733 In plagionite, PbSSb,Sl7,two lead atoms have six- and seven-fold co-ordination, respectively, in octahedral-like configurations. A third lead atom is surrounded by eight sulphur atoms in an arrangement which may be described as either a square antiprism or as a trigonal prism with neighbours along two face The structure of jordanite is a deformed PbStype, and is made up of alternate layers of metal sites (Pb+As) and sulphur atoms. Some of the metal sites have statistical nature; thus one site is occupied by 0.5Pb + 0.5As and another is occupied by 0.88Pb, giving a Lead sulphide forms with GeS2 in the unit-cell content of Pb27.8A~12.0S45.8.735 presence of GeS stable glasses in a large range of composition. Melts In the containing an excess of sulphur yield inhomogeneous glasses of the same GeS2-GeS system it is also possible to substitute SnS for GeS over a wide range. The Mossbauer spectra of the glasses are very similar to the compound SnGeS,, which crystallizes from the glasses on annealing.737The reaction of trimethylaluminium with PbS gives Me,Pb,
’” R. C. Pal, V.
P. Kapila, and S. K. Sharma, Indian J. Chern., 1974, 12, 651. H. C. Roberts and R. S. Eachus, J . Chem. Phys., 1973, 59, 5251. R. J. Booth, H. C. Starkie, M. C. R. Symonds, and R. S. Eachus, J.C.S. Dalton, 1973, 2233 ’”’ H. C . Starkie and M. C. R. Starkie, J.C.S. Dalton, 1974, 731. 730 M. C. R. Symonds, D. X. West, and J. G. Wilkinson, J.C.S. Dalton, 1974, 2247. ’” M. Ribes, J . Olivier-Fourcade, E. Philippot, and M. Maurin, Acta Cryst., 1974, B30, 1391. 7 3 2 T. lto and W. Nowacki, Z . Krist., 1974, 139, 8 5 . ’’’ T. Srikrishnan and W. Nowacki, Z. Krist., 1974, 140, 114. 734 S. A. Cho and B. J. Wuensch, Z . Krist., 1974, 139, 351. 73s T. Ito and W. Nowacki, Z. Krist., 1974, 139, 161. 7’6 A. Feltz and B. Voigt, Z . anorg. Chem., 1974, 403, 61. 737 A. Feltz, E. Schlenzig, and D. Arnold, Z. anorg. Chem., 1974, 403, 243. 727
’’’
304
Inorganic Chemistry of the Main-group Elements
Figure 38 ( a ) The molecular structure of, a n d (b) the arrangement of, the hetero -atoms about the lead in C,,H,,N,O,,Pb(SCN), (Reproduced by permission from Inorg. Chem., 1974, 13, 2094) lead, and bis(dimethyla1uminium) ~ulphide.'~'Lead thiolates Pb(SR), react with chloroboranes to afford thioboranes of the types Ph,B(SR)3-, (n = 0, 1, or 2).'" The complexation equilibria between Pb2+and ( f)-2,3-dimercaptosuccinic and (+)-2,4-dimercaptoglutaric acids have been studied.'""
'-"M. Boleslawski, S. Pasynkicwicz, and A. Kinicki, J. Organometallic Chem.. 1974, 73, 193. ''"R. H . Ci-agg, J . P. N. Husband, and A. F. Weston, J. 7norg. Nuclear Chem.. 1973, 35,3685. 740
L,. G. Egorova and V. L. Nirenburg, .1. Gen. CCtem. (U.S.S.R.),1973. 43, 1533.
Elements of Group IV
305
Nitrogen Derivatives. The preparation of simple amino-derivatives of bivalent germanium, tin, and lead has been reported. The reactions of SnCl,, PbCl,, or GeCl,,dioxan with the lithium salt LiNBu'(SiMe,) or LiN(SiMe,), in ether at 0 "C yield the compounds M[NBu'(SiMe,)], and M[N(SiMe,),],, respectively, as stable, diamagnetic, coloured, volatile, and low-melting materials which are soluble in hydrocarbon solvents. Several reactions of the tin(I1) derivatives have been described. In particular, the tin compound undergoes oxidative addition with (C5H,)(C0),FeMe [to give (C,H,)(CO),Fe{Sn(NR,),Me}], metathesis with acetic acid, ethanol, HCl, or cyclopentadiene [to afford Sn(02CMe),, Sn(OEt),, SnCl,, or Sn(C5H,),], redistribution with SnC1, or Sn(C5H,), [to give (XSnNR,), (X = C1 or C,H,)] and with LiCH(SiMe,), {to give Sn[CH(SiMe3),l2 and LiNR,}, and insertion with phenyl isocyanate [to give Sn(NPhCONR2),].'"' The compounds were deduced to be monomeric both in solution (cryoscopy) and in the vapour (mass s p e c t r ~ m e t r y ) , ~but ~ ' Sn[N(SiMe,),], has also been synthesized by Z ~ c k e r m a n who. , ~ ~ ~observes dimeric character also both in solution (osmometry) and in the vapour (mass spectrometry). Obviously, this discrepancy needs to be resolved. In addition, Zuckerman has also prepared several heterocyclic tin(I1)-nitrogen derivauves, some as THF s01vates.'~~ Irradiation of the germanium and tin derivatives M[N(SiMe,),], yields the very long-lived metal-centred radicals *M[N(SiMe,)2]3.743 The crystal structure of the lead cryptate C,,H3,N,O6,Pb(SCN), consists of discrete molecules (Figure 38a) in which the lead atom occupies a central position in the cavity of the macrobicyclic ligand. Each lead atom is surrounded by one sulphur [Pb-S = 3.121(3) A], three nitrogen [Pb-N= 2.642(10), 2.858(9), 2.909(9) A], and six oxygen atoms [Pb-0 = 2.729(7)-2.980(8) A], in an arrangement which approximates to a trigonal-capped irregular hexagonal pyramid (Figure 38b).'44 The effect of iron impurities on the thermal decomposition of lead azide has been ~tudied.'"~ The vibrational spectra of pure lead azide as well as of pure and doped samples that have been exposed to U.V.radiation have been examined,746-748 as have the i.r. spectra of the complexes NMe:[Sn(,NCO),]-, M(NCO),,2phen, and Pb(NCO),,bipy. In all the latter complexes, the NCO group is bonded to the metal uia the nitrogen atom.'"' Interactions of Bivalent Germanium and Tin Compounds, with Transitionmetal Derivatives. Several investigators have studied the ligand qualities of 74'
D. H . Harris and M. F. Lappert, J.C.S. Chern. Comrn., 1974, 8YS.
742
C. D. Schaeffer and J. J. Zuckerman, J. Amer. Chern. SOC.,1974, 96, 7160.
743
744
745
746 747
74x 749
J. D. Cotton, C . S. Cundy, D. H. Harris, A. Hudson, M. F. Lappert, and P. W. Lcdnor, J.C.S. Chem. Cornm., 1974, 651. B. Metz and R. Weiss, Inorg. Chern., 1974, 13, 2094. R. W. Hutchinson and F. P. Stein, J . Phys. Chem., 1974, 78, 478. K. Dehnicke, Z . anorg. Chem., 1974, 409, 311. S. P. Varma, F. Williams, and K. D. Moller, J. Chem. Phys., 1974, 60, 4950. S. P. Varma and F. Williams, J . Chem. Phys., 1974, 60, 4955. A. Y. Tsivadze, G. V. Tsintsadze, and T. L. Makhatadze, J . Gen. Chem. (U.S.S.R.),1974,44, 157.
306
Inorganic Chemistry of the Main- group Elements bivalent germanium and tin species. The photochemical reaction between 3benzothiazole-dichlorogermylene and chromium, molybdenum, and tungsten hexacarbonyls yields the complexes C,H,NS,GeCl,,M(CO), (M = Cr, Mo, or W).'" Group VI metal pentacarbonyl complexes of tin(11) halides and germanium dichloride have been obtained similarly from the hexacarbony1 and SnX, ( X = C1, Br, or I) or CsGeC1,. The resuiting M'X,,M(CO), (M = Sn, X = C1, Br, or I; M = Ge, X = C1) react further with NMe,'X in THF to form the complex anions [M(CO)sM'XJ.7s1 Mixed complex anions [M(CO),SnBr,_, C1,]- are formed when the metal hexacarbonyls are allowed to react with the mixed [SnBr,-,Cl,]- anions. The reactions of dibenzenechromium with these mixed halogenostannite anions lead to the formation of [Cr(SnBr,-, CI,),]" complex anions.752,753 The [SnCI,]- anion reacts with (C,&)M(CO), complexes (M = Cr or Mo) to form [M(CO),(SnC1,),]3- complex anions, whilst only C O displacement occurs in the reaction with (C,H,)V(CO), to yield the [(C,HS)V(CO),SnCI,),~-anion.753The reactions of [(Me,Si),CH],Sn with several transition-metal derivatives have been examined. With Cr(C0)6, the complex [(Me,Si),CH],Sn-+Cr(CO), is formed, the structure of which is shown in Figure 39, which confirms the
Figure 39 The structure of [(Me,Si),CH],SnCr(CO), (Reproduced from J.C.S. Chem. Cornm., 1974, 893)
''"P. Jutzi
and H. J . Hoffman. Chum. Ber., 1973, 107, 3616. H. Behrens. and E. Lindner, 2. unorg. Chem.. 1973, 401, 7 3 3 . '" T. Kruck, F. J . Becker, H. Breuer, K . Ehlert, and W. Rother. Z . unorg. Clwm.. 1474, 405, 95. 7T' '1'. Kruck and H. Breuer. Chem. Ru.. 1974. 107, 7 h 3 . 711
I). Uhlig,
Elements of Group IV 307 presence of a direct Sn-Cr bond [2.562(5)A]. The two carbon atoms and the chromium atom are coplanar with the tin. Other reactions are summarized in Scheme 4.754 Bis(methylcyclopentadieny1)tin reacts with [(Ph3P)dR,Sn)RhC11 purple, m.p. 184-187 "C
trans -[(R,S n),Mo(CO),]
"\\
/ orange, m.p. 204-205
"C
R,Sn
Fe -
[(Et,P)PtCI(SnR,)(SnR,Cl j]
brown, m.p. 167-170 "C
[Cp(CO),Mo-SnR,H] yellow, m.p. 128-130 "C
[Cp(CO),Mo-SnR,Me] brown, m.p. 103-105 "C
Reagents: i, [(Ph3P)3RhCI]; ii, (nbd)Mo(CO),; iii, [(Et3P)PtCl2I2; iv, [CpFe(CO),],; [Cp(CO),MoH]; vi, [Cp(CO),MoMe].
v,
Scheme 4
CO,(CO)~ slowly to form Sn[Co(CO),],. Tin(ri) halides, cyclopentadienyls, and P-keto-enolates react readily with Fe2(CO), to afford the dimeric [X,SnFe(CO),], derivatives, which undergo base-induced Sn-Fe bond fission to yield base-stabilized monomeric species.7s5Tin(I1) chloride inserts into the Fe-C bond of (C,H,)Fe(CO),R (R = CH,CH=CH,, CH,CMe=CH,, CH,CH=CHMe, or CH,CH=CMe,) in THF to yield the insertion product (C,H,)Fe(CO),SnCl,R. When treated with either excess SnC1, in THF or SnCl, in methanol, (C,H,)Fe(CO),CH,CMe=CH2 yields (C,H,)Fe(CO),SnCl, as the major product. This compound is the only product when R = CH=C=CH,, CH2C-CMe, or CH,CMe:. Tin(I1) iodide reacts with (C,H,)Fe(CO),CH,CH=CH, in benzene to form (C,H,)Fe(CO),I. Lead(i1) chloride does not react.7s6Tin(I1) chloride also inserts into (C,H,)Fe(CO),Me to give MeCl,SnFe(CO),(C,H,) together with traces of Cl,SnFe(CO),(C,H,), but with EtFe(CO),(C,H,) a mixture of C1,SnFe(CO),(C,H,) and Cl,Sn[Fe(CO),(C,H,)], is obtained. Reactions involving tin( 11) bromide gave mixtures of halogeno-metal carbonyls and halogenotinSix types of compound, (Bu,P)Co(CO),SnX,, [(Bu,P)Cometal carbonyl~.~'~ (CO),],SnX,, [(BuJ')Co(CO)3],SnX, [(BuJ')Co(CO)3],SnH, [(Bu,P)Co(CO),],Sn, and (BU,P),CO(CO)~X, have been isolated from the reactions of 754
755 756 757
J . D. Cotton, P. J. Davidson, D . E. Goldberg, M. F. Lappert, and K. M. Thomas, J.C.S. Chem. Comm., 1974, 893. A. B. Cornwell, P. G. Harrison, and J. A. Richards, J . Organometallic Chem., 1974, 76, C26. C. V. Magatti and W. P. Giering, J. Organometallic Chem., 1974, 73, 85. B. J. Cole, J. D. Cotton, and D. McWilliam, J. Organometallic Chem., 1974, 64, 223.
Inorganic Chemistry of the Main-group Elements 308 tin(r1) halides SnX2 (X = F, C1, Br, or I) and [ ( B u ~ P ) C O ( C O depending )~]~ on the reaction conditions, the mole ratio of reactants, and X. The reactions are thought to proceed either by direct insertion of SnX, into the Co-Co bond, or by the scission of this bond to give (Bu,P)Co(CO),SnX,, which may react further with [(Bu,P)CO(CO),],.'~~The hydride [(Bu,P)Co(CO),],SnH may also be obtained from tin(rr) sulphate and Na[Co(CO),(PBu,)] in aqueous diglyme, and is air-stable.'" A similar tin hydride has also been obtained from the reaction o f (C5H&3n with HMn(CO),. The crystal structure of the product, HSn[Mn(CO),],Sn[Mn(CO)5]zH, is shown in Figure 40, and it contains tin atoms in a strongly distorted tetrahedral envir~nrnent.'~" Red crystalline ReSn[CS(NH,),],CI,,H20 has been obtained by the reaction of HReO, in 3M-hydrochloric acid with thiourea and a
Figure 40 The structure of HSn[Mn(CO),],Sn[Mn(C0),1,H (Reproduced by permission from J . Organornetallic Chem., 1974,71,C 5 2 )
''' P. 75y
''('
Hackett and A. R. Manning, J.C.S. Dalton, 1974, 2257.
P. Hackett and A. R. Manning, J. Organornetallic Chem., 1974, 66, C17. K. D. Bos, E. J . Bulten, J . G. Noltes, and A. L. Spek, J. Organornetallic Chem., 1974. 71, CS2.
Elements of Group IV 309 solution of SnCl, in l0M-hydrochloric acid. Unit-cell data were obtained, but the structure could not be refined.761
3 Intermetallic Phases Binary Systems.-The temperature dependence of the solubility of Ge and of Sn in liquid sodium has been determined, together with the hypereutectic liquidus of the sodium-rich section of the Na-Sn phase diagram.762The compounds precipitating from these dilute solutions have been shown to be NaGe and Na,5Sn,. Solubility of the Group IV elements in liquid sodium increases in the order C < G e < S n < P b as the metallic character of the solute becomes more pronounced.76zThe crystal structures of Ca,Si, and Ca,Ge,, which are newly prepared compounds, have been determined;763 they crystallize in the tetragonal Cr,B, structure type and their unit-cell dimensions are compared with those of the isostructural interme tallics Sr,Si, and Ba,Si, in Table 21. The thermal stability of CaSi and several of its Under vacuum, thermal reactions with 0, and N, have been decomposition [reaction (75)] yields CaSi,. Reaction with 0, [reaction (76)] 2CaSi + CaSi, + Ca 4CaSi+ 3 0 2+ a’-Ca,SiO,
(75)
+ 2 C a 0 + 3Si
(76)
at high temperatures gives a’-Ca,SiO,, CaO, and Si. The oxidation is a multi-stage reaction and it has been possible to isolate the products of the initial stage (77) between 550 and 600°C. These products then react with 2CaSi + +O,4 CaSi, + CaO
(77)
0, at temperatures above 700°C to form y-Ca,SiO,, which transforms to a’-Ca,SiO, at 1000°C. With N,, the reaction products again depend on temperature; below 900 “C, Ca,SiN, is obtained by reaction (78), whereas between 900 and 1200°C pure CaSiN, is formed [reaction (79)].
4CaSi + 2N,
+ Ca,SiN,
CaSi + N, + CaSiN,
+ 3Si
(78) (79)
A new modification of SrSi and the new compound SrGeo.76 have been prepared and their structures determined .765 The two intermetallics are isostructural, crystallizing with orthorhombic symmetry; their unit-cell parameters are included in Table 21. A fascinating facet of these structures 7hI
762 763 7h4
765
V. G. Kuznetsov, G. N. Novitskaya, P. A. Koz’min, and L. V. Borisova, Russ. J. Inorg. Chem., 1973, 18, 214. P. Hubberstey and R. J. Pulharn, J.C.S. Dalton, 1974, 1541. B. Eisenmann and H. Schafer, Z . Naturforsch., 1974, 29b, 460. A. Gourves and J. Lang, Compt. rend., 1974, 278, C, 617. B. Eisenmann, H. Schafer, and K. Turban, Z . Naturforsch., 1974, 29b, 464.
3 10
Inorganic Chemistry of the Main-group Elements Table 21 Unit-cell parametersIA of Ca,Si,, CasGe3, Sr,Si,, Ba,Si,, SrSi, and SrGe0.7h Compound a b C
Ca& 7.64(2)
Ca,Ge, 7.74(2)
Sr,Si, 8.05(1)
Bassi, 8.436(6)
-
-
-
-
14.62(2)
14.66(2)
15.68(1)
16.53(1)
SrSi 12.98 4.89 18.03
SrGe,, 7 h 13.38 4.84 18.52
is the geometrical arrangement of the Group IV atoms, as shown in (41) and (42); they form a planar hexagon of Si (or Ge) atoms substituted in the
1, 2, 4,5 positions by four additional Si (or Ge) atoms. In SrGeo76,there are defects in the 1 , 2, 4, 5 positions, whereas in SrSi no indications of such defects could be found. The geometrical parameters of these units are summarized in the diagrams.'"' A group of Russian workers have determined the V-Si'"" and W-Si7"' phase diagrams. Four intermetallic compounds were observed in the V-Si system, V,Si (m.pt. 1935 "C), V,Si, (m.pt. 201 0 "C), V,Si, (peritectic, d. 1670"C), and VSi, (m.pt. 1680°C), and two in the W-Si system, W,Si3 (m.pt. 2095°C) and WSi, (m.pt. 2020°C). Tungsten deposited on PtSi, which in turn is deposited on silicon, will react to form WSi, at temperatures in excess of 750 0C;7"8silicon is the diffusing species and PtSi provides an unpassivated interface between the reactants. Various transition-metal silicides are also found on annealing (800-900 "C) other refractory metals (M=Ti, V, Cr, Ta, Mo, Ni, or NiCr) on PtSi on silicon. The stability of WSi, is evidenced by the fact that on annealing systems of the type W-MPtSi-Si, WSi, is formed in all cases except that where M = C r , when ca. 50% of the tungsten is transformed at 900"C.7"8The films formed when silicon is deposited on Mo from molten fluoride electrolytic baths have been identified as MoSi,;'"' this intermetallic imparts to Mo a remarkable resistance to high-temperature oxidation. The electrical conductivity of single crystals of Mn2?SL7has been determined parallel to and perpendicular to the c -axis;'" anisotropic behaviour was observed, particularly at low temperatures. Mn,,Si,, was found to be a
''''
Yu. A . Kocherzhinskii, 0. G. Kulik, and E. A. Shishkin. Doklady C'hern., 1973, 209, 333. Yu. A. Kocherzhinskii. 0. G. Kulik, E. A. Shishkin, and L. M. Yupko, Doklady C'hern.. 1974, 212, 782. '" A. K. Sinha. M. H. Read, and T. E. Smith, J. Electrochem. SOC.,1973. 120, 177.5. '" N. Petrescu, M. Petrescu, M. Britchi, and L. Pavel, Rev. Roumaine Chim., 1973, 18, 18.53. '"' G. Zwilling and H. Nowotny, Monatsh., 1974, 105, 666.
'*'
Elements of Group IV 311 p-type semiconductor, in agreement with literature data on similar defect silicides. The crystal structure of Fe6Ge, has been shown to be monoclinic, with unit-cell parameters a = 9.965(5), b = 7.826(5), c = 7.801(5) A, p = 109"40'*10';77' it has been coMpared to that of the isostructural Fe,Ga, and to those of the germanides and gallides of the other Group YIII transition metals. An Auger examination of a series of solid and liquid Pb-In solutions has shown that the relative intensity ratio of the Pb and In peaks is a sensitive indicator of changes in surface composition with respect to temperature and bulk The surface layers were richer in Pb than the bulk; this excess Pb concentration was decreased by the presence of oxygen but increased by carbon. Four investigations of the thermodynamic properties of systems contain~ ~ - ~ ~ deviations ~ ing Group IV elements have been ~ n d e r t a k e n . ~Positive from ideality were exhibited by Ge-Pb solutions (0.13 d xGed 0.92) at The thermodynamic properties temperatures between 900 and 1050 0C.773 of liquid Ge-Cu (1525 "C) and Ge-Au (1400 "C) have been determined using mass-spectrometric both systems exhibited negative deviations from ideal behaviour. In contrast, ys, in Si-Ag solutions (0.015 x S i s0.29) in the temperature range 1100-1325 "C was slightly greater than unity at all concentration^^^^ The enthalpy of formation of the intermetallic compound GeSe [AH*(GeSe) = - 10.1 2.0 kcal mol-'] and the absolute entropy [AS* (GeSe) = 16.9 f 2 cal K-' mol-'1 have been calculated from the results of a Knudsen effusion study of the sublimation of polycrystalline GeSe.776
*
Ternary Systems.-Phase equilibria in the Ge-Sn-Se,'" Sn-Na-Bi,77s and Sn-Cd-Hg779 systems have been determined. In the Ge-Sn-Se system, equilibria in the triangle GeSe,-SnSe2-SnSe have been described;"' the GeSe,-SnSe, and GeSe,-SnSe systems are quasi-binary, with eutectics at 569 "C and 50 rnol.O/o GeSe, and 580°C and 45.1 mol.% GeSe,, respectively. The ternary eutectic (556 "C) has the molecular composition GeSe2,SnSe,,0.75SnSe."' The effect of Na, which is employed as coolant in fast breeder reactors, on the freezing point of the Bi-Sn eutectic (139 "C), a fusible seal in these reactors, is to cause a decrease (to 125 "C) at concentrations up to 16 atom O/O Na.77RInteractions between G e and Sn and between 77 1
772
173
774
775 776 777 77x
779
B. Malarnan, M . J. Phillippe, B. Roques, A . Courtois, and J. Protas, Acta Cryst., 1974, B30, 2081. S. Berglund and G. A. Sornorjai, J. Chem. Phys., 1973, 59, 5.537. G. I. Batalin, V. A. Stukalo, E. A. Beloborodova, and A. I. Nikiforova, Russ.J. Phys. Chem., 1973, 47, 914. J. P. Hager, S. M. Howard, and J. H. Jones, Metallurg. Trans., 1973, 4, 2383. H . Sakao and J. F. Elliott, Metallurg. Trans., 1974, 5, 2063. H. Wiedemeier and E. A . Irene, Z . anorg. Chem., 1974, 404, 299. L. Bald6 and P. Khodadad, Compt. rend., 1974, 278, C, 243. T. F. Kassner and C. A. Youngdahl, Metallurg. Trans., 1973, 4, 2663. N. M. Atamanova and M. V. Nosek, Russ. J . Phys. Chem., 1973, 47, 1647.
Inorganic Chemistry of the Main -group Elements
3 12
Sn and Pb dissolved in liquid Na have been investigated using resistivity techniques.780A t the concentrations studied ( P.""" 1.r. and n.m.r. measurements over a temperature range indicate the presence of only one conformer for MeXP(=Y)Me2, where X,Y = 0 or S, but with MeSP(=Y)Et2 in the Iiquid phase two conformers are A stable tetrakis(trimethylsi1oxy)phosphonium iodide can be produced from Me,SiI and (Me,SiO),PO, but the corresponding bromide can be obtained only at low ternperat~res.~~" The iodide is also obtainable by treating trimethyl phosphate with four moles of Me3SiI. Details of the structure of phenylthiophosphonic anhydride (77) now publishedM5show a boat (ca. C,) ring conformation, with a trans arrangement of substituents. S\p./o\p/
Ph"
I
S P ('h
(77)
Although methylphosphonic acid has a polymeric structure, the compound sublimes readily at 150 "C and 1mmHg, and mass-spectrometric examination points to the trimer [MeP(0)0I3 being the most abundant is the predominant species from the species in the v a p o ~ r A . ~ dimer ~~ corresponding sulphur compound, but impurities such as [MeP(S)O], and [MeP(S)O], were also detected. Scrambling reactions between a number of phosphorus centres, i.e. MeP:, MeP(O):, or MeP(S):, and Me2Si: show that chlorine atoms are preferentially bonded to ~ilicon."~' Samples of methyl(MeO),P(0)O[P(O)OMe].P(O)(OMe2)2, where ated polyphosphates n =0-2, can be obtained by molecular distillation of an equilibrated mixture of P,O, and trimethyl p h o ~ p h a t e . " ~ ~ Thermal decomposition of 1-hydroxyethylidenediphosphonicacidM9gives a polyacid containing the cyclic anion (78), previously recognized in the product from the reaction of acetyl chloride and phosphorous acid.
(78) 462 463
464 465
466 467
468 469
R. Bravo, M. Durand, J.-P. Laurent, and F. Gallais, Compt. rend., 1974, 278, C, 1489. A. B. Remizov, I. Ya. Kuramshin, A. V. Aganov, and G. G. Butenico, Doklady Chem., 1973, 208, 134. H. Schmidbaur and R. Seeber, Chem. Ber., 1974, 107, 1731. J. J. Daly and F. Sam, J.C.S. Dalton, 1973, 2032. K. Moedritzer, Phosphorus, 1974, 3, 219. K. Moedritzer and J. R. Van Wazer, Inorg. Chern., 1973, 12, 2856. R. A. Schep, S. Norval, and J. H. J. Coetzee, Inorg. Chem., 1973, 12, 2711. A. J. Collins, G. W. Fraser, P. G. Perkins, and D . R. Russell, J.C.S. Dalton, 1974, 960.
374 Inorganic Chemistry of the Main -group Elements Evidence for five-co-ordinate phosphorus(v) species with essentially square-pyramidal structures has been observed in a number of spirocyclic Complete structural data are available systems, such as (79)'" and (80).471,472
for (80) where R=Me473or F;474in the latter the co-ordination is intermediate between a trigonal bipyramid and a square pyramid. Factors influencing the structures are discussed in detail, but a major feature seems to be the reduced ring strain in the square-pyramidal form. Six-co-ordinated phosphorus(v) compounds are still relatively rare, but recently three such compounds containing three different bidentate oxygen ligands (derived from ethylene glycol, mandelic acid, benzil, or 2-hydroxy2-methylpropionic acid) have been synthe~ized.~~' Detailed structures have now been determined for (81) by electron diffraction476and for two substituted 1,3,2-dioxaphosphorinansby X-ray
(81) X = O o r S
In the cyclic acyl phosphate (82), the C,O,P ring has a half chair c ~ n f o r r n a t i o nwhile , ~ ~ ~ the compound obtained from a MichaelisArbuzov reaction of l-phospha-2,8,9-trioxa-adamantaneand benzyl chloride has been shown by an X-ray study to have a bicyclic structure (83).480 There is now considerable work o n metal complexes of substituted phosphorus-oxygen species. For example, the Group 111 trialkyls lose one mole of an alkane with phosphinic acids X,P(O)OH, where X = M e , H, F, or C1, 470 471 472
473 474 475 470
477 478 47Y
480
J. A. Howard, D. R. Russell, and S. Trippett, J.C.S. Chem. Comm., 1973, 856.
R. R. Holmes, J . Amer. Chem. SOC.,1974, 96, 4143. H. Wunderlich, D. Mootz, R. Schmutzler, and M. Wieber, Z. Naturforsch., 1974, 29b, 32. H. Wunderlich, Acta Cryst., 1974, B30, 939. H. Wunderlich and D. Mootz, Acta Cryst., 1974, B30, 935. M. Koenig, A. Munoz, D. Houalla, and R. Wolf, J.C.S. Chem. Comm., 1974, 182. V. A. Naumov, V. N. Semashko, A. P. Zav'yalov, R. A. Cherkasov, and L. N. Grishina, 1. Struct. Chem., 1973, 14, 739. R. E. Wagner, W. Jensen, W. Wadsworth, and Q. Johnson, Acta Cryst., 1973, B29, 2160. W. Saenger and A. Mikolajczyk, Chem. Ber., 1973, 106, 3519. G. D. Smith, C. N. Caughlan, F. Ramirez, S. L. Glaser, and P. Stern, J. Amer. Chem. SOC., 1974, 96, 2698. S. R. Holbrook, D. van der Helm, and K. D. Berlin, Phosphorus, 1974, 3, 199.
Elements of Group V
375
to give R,MO(O)PX, species which are associated through bridging X2P02 groups.*" Vibrational data point to trimerization, with puckered twelvemembered rings, for M = Al but dimerization when M = Ga or In.482Complex formation between tin(rv) chloride and Me,P(0)OMe,"83Me,P(0)C1,*83 (RO),P(O)SMe,"8' or Ph(RO)P(0)H485gives in general 1:2 adducts which may be mixtures of geometric isomers. The donor site is the phosphoryl oxygen atom in all cases. Different kinds of tin species, e.g. R2Sn(P02H,)2, R2SnP03X ( X = F or OH), and (R,Sn),(PO.&, result when dialkyltin dichlorides and the sodium salts of the acid react in w a t e r y and implicationson their structures follow from i.r. and ""Sn Mossbauer data. Complex compounds also result when triethyl phosphate*" or tetraethyl methylenedipho~phonate~~~ and a wide range of metal halides react in the 100-250 "C temperature range. Representative formulae for the former are M[OOP(OEt),], for M=Al, Ga, In, Sc, Y, Ti, V, Cr, or Fe and M[OOP(OEt),], for M = Fe, Cu, or VO, but polymeric structures are indicated on the basis of insolubility and high thermal stability. Magnetic and spectral measurements for these and similar complexes have been obtained and correlated~'" Species which involve a bridging chlorine atom in addition to phosphinate bridges have been recognized as the products from anhydrous CrC1, reactions with the appropriate phosphinic acid.490(See also refs. 338 and 339).
Monophosphates. A timely review491surveys quantum-mechanical calculations on 3d orbital participation in bonding, and, in addition to data on 481
482
483
484
48s
486
487 488 489
490
491
B. Schaible, W. Haubold, and J. Weidlein, Z . anorg. Chem., 1974, 403, 289. B. Schaible and J. Weidlein, Z. anorg. Chem., 1974, 403, 301. A. N. Pudovik, I. Ya. Kuramshin, E. G. Yarkova, A. A. Muratova, A. A. Musina, and R. A. Manapov, J. Gen. Chem. (U.S.S.R.), 1973, 43, 1220. I. Ya. Kurashin, A. A. Muratova, E. G. Yarkova, A. A. Musina, F. Kh. Izmailova, and A. N. Pudovik, J. Gen. Chem. (U.S.S.R.), 1973, 43, 1446. A. A. Muratova, E. G. Yarkova, V. P. Plekhov, N. R. Safiullina, A. A. Musina, and A. N. Pudovik, J. Gen. Chem. (U.S.S.R.), 1973, 43, 1677. T. Chivers, J. H. G. van Roode, J. N. R. Ruddick, and J. R. Sarns, Canad. J . Chem., 1973, 51, 3703. C . M. Mikulski, L. L. Pytlewski, and N. M. Karayannis, Z . anorg. Chem., 1974, 403, 200. C. M. Mikulski, N. M. Karayannis, L. L. Pytlewski, R. 0. Hutchins, and B. E. Maryanoff, J. Inorg. Nuclear Chem., 1973, 35, 4011. C . M. Mikulski, N. M. Karayannis and L. L. Pytlewski, J. Inorg. Nuclear Chem., 1974, 36, 971. H. D. Gillman, P. Nannelli, and B. P. Block, J. Inorg. Nuclear Chem., 1973, 35, 4053. M. E. Dyatkina and N. M. Klimenko, J. Stmct. Chem. (U.S.S.R.), 1973, 14, 157.
3 76 Inorganic Chemistry of the Main -group Elements PO:- and PF;, the sulphur, chlorine, silicon, and aluminium analogues have been treated. New a b initio calculations have been reported on PO:-,'" and data from X-ray emission and p.e.s. for several second-row oxyanions, including PO:-, give good agreement with the results of such computation~.,~~ Refinement of the structure of H,PO,,iH,O using neutron-diffraction data shows the presence of two different acid molecules hydrogen-bonded to each other and to the water The effect of "0 on the p H of solutions of H3PO4 has been investigated, as previous observations implied that hydrogen-bonding tendencies were lowered by the presence of As expected, the p H of the acid in pure H,"O is significantly lower than in H,160. Evidence has been presented for the formation of the radical -P(OH)l by y-irradiation of phosphoric acid in sulphuric acid but with arsenic acid the species produced is .As(OH),."~~ Structural studies for a number of hydrogen monophosphates are concerned with the hydrogen atom positions, for example in NaH,PO,,""' NH,H,P04,498and Ca(H2P04)2.499 Problems of crystal twinning in stercorite (NaNH,HPO,,H,O) have been inve~tigated,'~~ and the structure of synthetic magnesium whitlockite, Ca18Mg2H2(P04)14, has been shown to be hexagonal (space group R 3 c ) , with similarities to the p -Ca3(P04), Co-ordination about sodium, which gives rise to a complex of composition [Na6F(OH,),,]5+,is the feature of interest in the structures of the double salt NaF,2Na3PO,, 19 H 2 0 and its arsenic analogue.502In brazilianite, NaA1,(P04)2(0H)4,the structure is based on chains of edge-sharing A106 octahedra linked by PO, tetrahedra, giving cavities which contain the sodium ions.5o3 show the presence of P03F2Structures for LiKP03FSo4 and p -Na2P03FSo5 tetrahedra, and in SnP03F506there are sheets of P03F2- ions alternating with tin(I1) ions, giving a structure very similar to that of SnHPO,. Powder data for Na3P03S,12H,0, the nonahydrate, and the anhydrous material give unit-cell dimensions for each form,507and single-crystal data 4q2 491 494
496
497 49H
4y9 500
501
'04 505
H. Johansen, Theor. Chim. Acta, 1974, 32, 273. J. A. Connor, I. H. Hillier, M. H. Wood, and M . Barber, J.C.S. Faraday 11, 1974,70, 1040. B. Dickens, E. Prince, L. W. Schroeder, T. H. Jordan, Acta Cryst., 1974, B30, 1470. A. 1. Kudish, D. Wolf, and S. Pinchas, J. Inorg. Nuclear Chem., 1973, 35, 3637. I. S. Ginns, S. P. Mishra, and M. C. R. Symons, J.C.S. Dalton, 1973, 2509. M. Catti and G. Ferraris, Acta Cryst., 1974, B30, 1. A. A. Khan and W. H. Baur, Acta Cryst., 1973, B29, 2721; A. W. Hewat, Nature, 1973, 246, 90. B. Dickens, E. Prince, L. W. Schroeder, and W. E. Brown, Acta Cryst., 1973, B29, 2057. G. Ferraris and M. Franchini-Angela, Acta Cryst., 1974, B30, 504. R. Gopal, C. Calvo, J. Ito, and W. K . Sabine, Canad. J. Chem., 1974, 52, 1155. W. H. Baur and E. Tillmanns, Acta Cryst., 1974, B30, 2218. B. M. Gatehouse and B. K . Miskin, Acta Cryst., 1974, B30, 1311. J. L. GalignB, J. Durand, and L. Cot, Acta Cryst., 1974, B30, 697. J. Durand, L. Cot, and J. L. Galignk, Acta Cryst., 1974, B30, 1565. A. F. Berndt, Acta Cryst., 1974, B30, 529. M. Palazzi, Bull. SOC. chim. France, 1973, 3246.
Elements of Group V
377
for the imidodiphosphate Na4(P03NHP03),10H20 give molecular parameters similar to those in the diphosphate analogue.5o8 In addition, the hydrogen-bond systems in these two compounds are virtually identical, implying that the imido-hydrogen atom is effectively blocked from participation by its position. The spectra of lithium phosphate glasses doped with transition elements can be correlated with octahedral co-ordination for Cr3+,Mn3+,Fe2+,Fe3+, Ni2+, and Cu2+,while tetrahedral co-ordination is more appropriate for CO'+.~O~ 1.r. and Raman spectra have been measured for LiM"XB4, where M"= Mg, Ni, Co, Mn, Fe, or Cd and X = P or Dehydration of M&(P04)2,22H20to the octahydrate is speeded up by adding MgHP04,3H20and Na2C03.5" New i.r. and Rarnan data for a-zirconium phosphate indicate asymmetry in the lattice water rn01ecules,~~'and exchange of labelled phosphate between an aqueous solution and the solid exchanger has been reexamined.513Forward and reverse Li-K exchange isotherms have been determined on crystalline zirconium p h o ~ p h a t e , 5and ~ ~ ~to avoid hydration complications, the system has been investigated in molten LiN03-KN03 Exchange reactions using the half-exchanged form, mixtures at 300 0C.514b A zirNaZrH(P04)2,5H20, have also been extensively conium phosphosilicate exchanger can be used to separate neptunium and plutonium.517 Three new phosphomolybdate structures, Na,[H2Mo,P,023(H20)10],518 Na3[H6M09P034(H20)r],519 and (NH4)5[HMo5P2024(H20)3],520 have been determined, each showing significant new features. The formula &[P2W,,O,,],xH2O is suggested for 18-tungsto-2-phosphoric acid on the basis of po tentiome tric titrations in a number of non-aqueous Similar basicity measurements point to an increase in the number of dissociable protons in molybdo-phosphoric acids as the molybdenum atoms are replaced by ~anadium.~"
50H '09 'lo 5"
'12
'14
515
516
517
'I8 519
520
'*'
M. L. Larsen and R. D. Willett, Acta Cryst., 1974, B30, 522. M. Berretz and S. L. Holt, J. Inorg. Nuclear Chem., 1974, 36, 49. M. Th. Paques-Ledent and P. Tarte, Spectrochim. Acta, 1974, 30A, 673. T. Kanazawa, T. Umegaki, and E. Wasai, Chem. Letters, 1974, 817. S. E. Horsley, D. V. Nowell, and D. T. Stewart, Spectrochim. Acta, 1974, 30A, 535. M. K. Rahman and J. Barren, J. Inorg. Nuclear Chem., 1974, 36, 1899. (a) G. Alberti, U. Constantino, S. Allulli, M. A. Massucci, and N. Tomassini, J. Inorg. Nuclear Chem., 1974, 36, 653; (b) ibid., p. 661. G. Alberti, U. Constantino, and J. P. Gupta, J. Inorg. Nuclear Chem., 1974,36,2103, 2109. S. Allulli, A. La Ginestra, M. A. Massucci, M. Pelliccioni, and N. Tomassini, Inorg. Nuclear Chem. Letters, 1974, 10, 337. R. Ooms, P. Schonken, W. D'Olieslager, L. Baetslt, and M. D'Hont, J. Inorg. Nuclear Chem., 1974, 36, 665. B. Hedman, Acta Chem. Scand., 1973, 27, 3335. R. Strandberg, Acta Chem. Scand. (A), 1974, 28, 217. J. Fischer, L. Ricard, and P. Toledano, J.C.S. Dalton, 1974, 941. L. P. Maslov and N. A. Tsvetkov, J. Gen. Chem. (U.S.S.R.), 1973, 43, 954. N. V. Cheu and N. A. Polotebnova, Russ. J. Inorg. Chem., 1973, 18, 1157.
378 Inorganic Chemistry of the Main-group Elements Apatites. Interest in this subject continues in view of its importance in biological systems. A hydroxylapatite with similar properties to biological apatites results when ammoniacal CaCl, and ammonium phosphate solutions are added dropwise to an ammonia buffer at pH9.523The uptake of lead by synthetic calcium hydroxylapatite has been The value of i.r. spectroscopy in studying substituted apatites is stressed by Trombe and M ~ n t e land , ~ ~the ~ technique has been used to study calcium hydroxylapatite and its is0topically substituted species526and the fluoride Ca5(P04)3F.527*52” Hydroxylapatite decomposes slowly in dry air at 1250 “C, contrary to reports that it is stable to 1450”C, giving Ca3(P04),and Ca4P,09.529 The existence of oxyapatite, Ca,,(P04)60, has been confirmed, and the compound is readily prepared by heating a carbonated apatite at between 800 and 1000 OC.”’ At higher temperatures, the lattice is degraded, however. Conversion into a peroxy species occurs on heating at ca. 900°C in a stream of oxygen.531The thermal behaviour of basic calcium phosphates indicates the formation of pseudo-apatitic structures when Ca:P is greater than 3 :2,532and new apatite-like structures with the composition M9+yNa,(Po4)&+zy02, where M=Ca or Sr, can be prepared by direct reaction between M,(PO4)2 and Na,B40,,10Hz0 at 1400 0C.533 The fluorine in fluoroapatite can be substituted by chlorine on treatment with an NO,-NOC1 mixture at 1000”C,534and the B-type carbonate apatites lose carbon dioxide on heating between 700 and 1000 “C, giving CaO and l~ydroxylapatite.”~ X-Ray data indicate strong similarities between the structure of strontium chloroapatite and the fluoro- and hydroxyanalog~~es.’~~
Diphosphates. Recent calorimetric measurements have been used to give thermodynamic data on the ionization of diphosphoric acid537and the formation of [MP207]3-,where M=Li, Na, or K.’38 Methods are now available for the formation of the hydrated salts NaAlP,O,, Ga,(P,O,),, and P. Jervae and H. E. L. Madsen, Acta Chem. Scand. (A), 1974, 28, 477. W. S. Chicherur and S. V. Chiranjeevi Rao, Indian J. Chem., 1973, 11, 603. 5 2 5 3.-C. Trombe and G. Montel, Compt. rend., 1974, 278, C, 777. B. 0. Fowler, Inorg. Chem., 1974, 13, 194, 207. s27 D. M. Adarns and I. R. Gardener, J.C.S. Dalton, 1974, 1505. D. K. Arkhipenko, B. A . Orekhov, and R. G . Knubovets, Optics and Spectroscopy, 1973, 34, 425. ’” T. R. Narayanan Kutty, Indian J. Chern., 1973, 11, 695. 530 J.-C. Trombe, Ann. Chim. (France), 1973, 8, 251. s31 J.-C. Trombe, Ann. Chirn. (France), 1973, 8, 335. s32 A. Delay, C. Friedli, and P. Lerch, Bull. SOC.chim. France, 1974, 828, 839. 533 C. Calvo and R. Faggiani, J.C.S. Chem. Cornm., 1974, 714. 534 J.-C. Trombe and G. Montel, Cornpt. rend., 1974, 278, C, 1227. 5 3 5 J.-C. Labarthe, G. Bonel, and G. Montel, Ann. Chm. (France), 1973, 8, 289. K. Sudarsanan and R. A. Young, Acta Cryst., 1974, B30, 1381. ”’ V. P. Vasil’ev, S. A. Aleksandrova, and L. A . Kochergina, Russ. J. Inorg. Chem., 1973, 18, 1549. 538 V. P. Vasil’ev and S. A. Aleksandrova, Russ. J. Inorg. Chem., 1973, 18, 1089. 523
524
”‘ ’”
Elements of Group V
379
In4(P207)3.539 Equilibrium constants for complex formation between di- or other short-chain poly-phosphates and [Cu(NH,),T' are not in the order expected on the basis of anion charges, probably indicating different structures for the c~mplexe~.'"~ The species obtained from Mn" and similar short-chain phosphates have been investigated by polarography and paper ~hromatography.~"'An SN2-type process with activation energies in the range 19-28 kcal mol-1 is envisaged for the hydrolysis of both di- and triphosphate in a series of mixed aqueous A POP angle in the region of 130" is found in the structures of both ~P,0,,3H,05"3and KzH,P,07,~H,0,5"'while in the latter the bridge oxygen appears to be bonded to potassium and the anions are connected in a spiral form by strong hydrogen bonds. In KAlP,O,, the bridge angle is reduced to 123.2", with the two PO, groups having an almost staggered conformat i ~ n . ~The " ~ bridge and terminal P-0 distances are 1.607 and 1.509& respectively, similar to those in the structures mentioned above.
Cyclic Metaphosphates. Dehydration of NaH2P04, Na2HP04, and Na,PO, with n-butyric, isobutyric, or succinic anhydrides in acetic acid follows the same route as acetic anhydride, giving trimetaphosphates as the major Conditional stability constants for the formation of species which appear to involve electrostatic interactions only have been determined for the systems involving Ca", Sr2+,ZnZ+,and Co2' and the tri-, tetra-, hexa-, and octa-metaphosphate anions.54' A new preparation has been reported for the blue titanium(rr1) tetrametaphosphate Ti4(P,Ol2),,which on heating gives P,O, and TiP,O,.'"" Full details of the structure of m4(P40,2)have now been reported? and in contrast to previous observations the anion here has 3 (S,) symmetry. This points to flexibility of the ring, which can adopt a conformation best suited to the cation. Exocyclic P-0 distances are 1.44 and 1.51 A, while the P-0-P bridge distances and angles are 1.6213, and 133.3", respecand a tively. The hexametaphosphate cUzLi2P60~8has been p~epared,5'~ crystallographic study shows terminal and ring P-0 distances of 1.48 and 1.59 A, re~pectively.~'~ Polyphosphates. The force field of the triphosphate ion P301,'- has been estimated, leading to the forms of the normal vibrations and assignment of 539 540
541
542 543 544
545 546 547 548 549
551
A. Muck, T. Hynie, J. Stejskal, and B. HAjek, Z.Chem., 1974, 14, 69. H.Waki, K. Yoshimura, and S. Ohashi, J. Inorg. Nuclear Chem., 1974, 36, 1337. S. Aoki and Y. Arai, Nippon Kagaku Kaishi, 1974, 60. M. Watanabe, Bull. Chem. SOC.Japan, 1974, 47, 2048. Y.Dumas and J. L. GalignC, Acta Cryst., 1974, B30, 390. Y.Dumas, J. L. Galignk, and J. Falgueirettes, Acta Cryst., 1973, B29, 2913. H.N. Ng and C. Calvo, Canad. J. Chem., 1973, 51, 2613. M. Watanabe, H. Usami, and M. Sugase, Bull. Chem. SOC. Japan, 1973, 46, 2885. G. Kura, S. Ohashi, and S. Kura, J . Inorg. Nuclear Chem., 1974, 36, 1605. M.Tsuhako, I. Motooka, and M. Kobayashi, Chem. Letters, 1974, 435. J. K. Fawcett, V. Kocman, and S. C. Nyburg, Acta Cryst., 1974, B30, 1979. M. Laugt, A . Durif, and C. Martin, J . Appl. Cryst., 1974, 7, 448. M. Laugt and A. Durif, Acta Cryst., 1974, B30, 2118.
380
Inorganic Chemistry of the Main -group Elements
the In addition to Cs21nP301,,8H20,basic salts are formed from aqueous solutions of InC1, and CssP3010,5s3 and complex formation between tripolyphosphate and rare-earth ions has been followed potentiometrially.^^, Guanidinium polyphosphates are the products when ammonium dihydrogen phosphate is heated with di~yandiarnide,”~ and, as expected, increasing the temperature gives larger amounts of the more highly condensed species, with 3-10 phosphate units. New heteroionic-type compounds have been discovered during work on the ~ 0 3 - W 0 3 - M o 0 3 ternary Single-crystal measurements show the usual helical chain of condensed phosphate groups in the structures of Nd(PO,),,”’ Yb(Po3)3,’58 K2Cu(P03)4,5s9 and K2Co(P03),.559In the ultraphosphates NdP501,5s7and SmP,014,560 two such polyphosphate chains are cross-linked by PO, tetrahedra, giving PsO1, as the repeating unit. The distribution of phosphate units in sodium sulphato-phosphate glasses can be determined by 31Pn.m.r. The structure of Si,O(PO,), is isotypic with the germanium analogue and consists of isolated Si06 and Si,07 groups linked by PO, tetrahedra into a three -dimensional net. 562 In the antimony phosphate SbO(H2P04),H20 there are infinite layers of PO, and SbO, tetrahedra sharing corners, with water molecules between the layers.s63There are linked PO, tetrahedra and Ti06 octrahedra in the structure of KTiOP0,,564and PO, and VO, groups in -VPO~Y
Phase Studies. The following systems have been investigated; formulae in square brackets are identified phases: Na3P04-Mg3(P04)2 [NaMg4(P04)3 and NaMgP04];566 Na2HP04-(NH&HP04-H20 [NaNH4HP04,4H20],567 KHtP04-N&H2P04-H20;568 KH2P04-CO(NH2)2-H20;568 NH4H2P04C O ( N H Z ) ~ - H Z OAg3P04-AgP03 ;~~~ [Ag4P207];570 LiP03-Ni(P0& [LiNi 552
Yu. B. Kirillov and K. I. Petrov, Russ. J . Inorg. Chem., 1973, 18, 964.
”’ G. V. Rodicheva, E. N. Deichman, I. V. Tananaev, and Zh. K. Shaidarbekova, Russ. J. Inorg. Chem., 1973, 18, 1352. M. M. Taqui Khan and P. R. Reddy. J. Inorg. Nuclear Chem., 1974, 36, 607. 5 5 5 E. Kobayashi, Bull. Chem. SOC.Japan, 1973, 46, 3795. 4 5 6 L. V. Semenyakova and I. G. Kokarovtseva, Russ. J. Inorg. Chem., 1973, 18, 1632. 557 H. Y.-P. Hong, Acta Cryst., 1974, B30, 468. 558 H. Y.-P. Hong, Acta Cryst., 1974, B30, 1857. 5 s q M. Laugt, I. Tordjman, G. Bassi, and J. C. Guitel, Acta Cryst., 1974, B30, 1100. 5h0 D. Tranqui, M. Bagieu, and A. Durif, Acta Cryst., 1974, B30, 1751. F. G. Remy and J. R. Van Wazer, J. Inorg. Nuclear Chem., 1974, 36, 1905. 5 6 2 H. Mayer, Monatsh., 1974, 105, 46. s63 C. Sarnstrand, Acta Chem. Scand. (A), 1974, 28, 275. 564 I. Tordjman, R. Masse, and J. C. Guitel, Z. Krist., 1974, 139, 103. ”‘ B. Jordan and C. Calvo, Canad. J. Chem., 1973, 51, 2621. ”‘ J. Majling, Chem. Zvesti, 1973, 27, 732. 5h7 R. F. Platford, J. Chem. and Eng. Data, 1974, 19, 166 568 A. G. Bergman, A. A. Gladkovksaya, and R. A. Galushkina, Russ. J. lnorg. Chem., 1973,18, 1047. 5h‘) R. Kummel and R. Fahsl, Z. anorg. Chem., 1973, 402, 305. 570 R. K. Osterheld and T. J. Mozer, J. Inorg. Nuclear Chem., 1973, 35, 3463 554
381
Elements of Group V
ICP03-NiP03 [KNi(PO& and K2Ni(P03)4];571 NaP03-KP03 [NazKP309];572 Na4P207-M&P20,;:73 Na,P207-Zn2P,07;573 RbP03-CU(P03)2[ C U ~ R ~ ~KPO3-Al2O3 P ~ ~ ~ ~ [&f%(p@10)3, ] ; ~ ~ ~ K6&(p207)3, and K3A12(P04)3];’7’T1P03-Cu(P03)2 [CUTI(PO~)~ and C U ~ T ~ ~ P ~ ~ ~ ~ ] . ~
Powder Diffraction Data. Data for the following compounds are available: ’~ NaMP04,9H,0 (M = Sr M,PO, (M = K, Rb, or C S ) ; ~Na4Mg(P04)2,2H,0;578 or Ba);”” MTh,(PO,), (M = Cu or Tl);”’ CO~(PO~),;~”’ ammonium tri- and tetra-polypho~phates.’”~ Bonds to Sulphur or Selenium.- Values for the dissociation energies (DE) of the diatomic species PS, PSe, and m e , determined by Knudsen-cell mass Some 31P spectrometry, are 438, 360, and 294 kJ mol-’, re~pectively.~’~ n.m.r. data for P4S3in the polycrystalline and in a nematic phase are now a ~ a i l a b l e . ’ Displacement ~~ of one carbon monoxide group from Mo(CO)~occurs on reaction with P4S3,giving (84),586and crystal data show
co OC\
’co
I /Co
Mo
I ‘co
that, with the exception of the P-S bonds to the attached phosphorus atoms, the dimensions of the cage change little. Carbon disulphide inserts rapidly into -the P-N bond of N-dimethylaminophosphines containing phosphorus-sulphur bonds to give thiocarbamoyl derivatives such as Me,NC(S)SPR’R’, but similar reactions with 571 s72
573
57J 575 576 577 578 579
580 581
582
583
584
585 s86
P. de Pontcharra and A . Durif, Compt. rend., 1974, 278, C, 175. C. Cavero-Ghersi and A. Durif, Compt. rend., 1974, 278, C, 459. P. Fellner and J. Majling, Chem. Zuesti, 1973, 27, 728. M. Laugt, Compt. rend., 1974, 278, C, 1197. S. I. Berul’ and N. I. Grishina, Russ. J. Jnorg. Chem., 1973, 18, 1334. M. Laugt, Compt. rend., 1974, 278, C, 1497. R. Hoppe and H. M. Seyfert, Z . Naturforsch., 1973, 28b, 507. A. Ghorbel, F. d’Yvoire, and C. Dorkmieux-Morin, Bull. SOC.chim. France, 1974, 1239. E. Banks and R. Chianelli, J. Appl. Cryst., 1974, 7 , 301. M. Laugt, J. Appl. Crysf., 1973, 6, 299. A. G. Nord; Acta Chem. Scand.(A), 1974, 28, 150. K. R. Waerstad and G. H. McClellan, J. Appl. Cryst., 1974, 7 , 404. J. Drowart, C. E. Myers, R. Szwarc, A. van der Auwera-Mahieu, and 0. M. Uy, High Temp. Sci., 1973, 5, 482. E. R. Andrew, W. S. Hinshaw, and A. Jasinski, Chem. Phys. Letters, 1974, 24, 399; E. R. Andrew, W. S. Hinshaw, M. G. Hutchins, and A. Jasinski, ibid., 1974, 27, 96. N. Zumbulyadis and B. P. Dailey, Chem. Phys. Letters, 1974, 26, 273. A. W. Cordes, R. D . Joyner, R. D . Shores, and E. D. Dill, Inorg. Chem., 1974, 13, 132.
3 82
Inorganic Chemistry of the Main- group Elements
carbon dioxide do not occur.s87Full structural details are available for the trisulphide (85).s’’ A previously unknown class of compounds, SS-dialkyl
hydrogen phosphorodithioites (RS),POH, can be prepared by hydrolysis of the corresponding chloride, but purification by distillation is not p~ssible.”~ y-Irradiation of PSCI, generates SPCI;, SPCl,, and SPCl: radicals, but the corresponding bromide gives SPBr; and SPBr2.590 Photoelectron spectra have been reported for SPCI3-,(NMe2),, showing that the first ionization potentials involve electrons significantly localized on ~ulphur.~” Assignments have been given for the vibrational spectra of [P(SMe),]+SbCl;.sg2 The dithiophosphinic acids in the series (C,H,,+,),P(S)SH, where n = 2-18, and their zinc salts can be rapidly detected and separated by thin-layer chromat~graphy.’’~ Preparative methods have been devised for two new phosphonothioic dichlorides RP(S)C12, where R = 2-chlorocyclohexyl and 1-cyclohexen-1yl,594and for the pentafluorophenyl derivatives C,F,P(S)X,, R(C,F5)P(S)X, and (C,F5)2P(S)X.’9’ Compounds with the general formula [R,P(X)],Y, where X and Y = O or S, have been prepared for detailed n.m.r. Me,P(S)Br
2R,P(S)Br
+ +
Me2P(S)ONa 2NaSH
-
--+
[Me,P(S)I20 + NaBr
[R,P(S)],S
+
2NaBr
+
H,S
(18) (19)
studies, and among the reactions used are those in equations (18) and (19).’, The P-S-P bridge in thiodiphenylphosphinic anhydride (86) is 5x7 588
5x9
590
591
592 593
594
5y5
5 96
H. Boudjebel, H. GonGalves, and F. Mathis, Bull. SOC.chim. France, 1974, 1671. M. G . Newton, H. C . Brown, C. J . Finder, J . B. Robert, J . Martin, and D. Tranqui, J.C.S. Chem. Comm., 1974, 455. S. F. Sorokina, A. I. Zavalishina, and E. E. Nifant’ev, J . Gen. Chem. (U.S.S.R.), 1973, 43, 748. S. P. Mishra, K. V. S. Rao, and M. C. R. Symons, J. Phys. Chem., 1974, 78, 576. V. I. Vovna, S. N. Lopatin, R. Pettsold, F. I. Vilesov, and M. E. Akopya, Optics and Spectroscopy, 1973, 34, 501. H. Stoll and J. Goubeau, 2. anorg. Chem., 1974, 406, 307. J. Auvray and A. Lamotte, Bull. SOC.chim. France, 1974, 407. A. F. Grapov, V. A. Kozlov, E. I. Babkina, and N. N . Mel’nikov, J . Gen. Chem. (U.S.S.R.), 1973, 43, 1904. M. Fild and T. Stankiewicz, Z . Naturforsch., 1974, 29b, 206. G. Hagele, W. Kuchen, and H. Steinberger, Z . Naturforsch., 1974, 29b, 349.
EEements of Group V
383
broken when reaction occurs with bis(dimethy1amino)sulphane [see equation (2O)],”’ and bridge cleavage also occurs when the disulphide (RO),P(S)SSP(S)(OR), reacts with either primary or phenylhydra~ine.’~’ With the former the products are N-alkyl-S -phosphinohydrosulphamines (RO),P(S)SNHR, but the latter gives the salts [PhNHNHJ[(RO),PS,]-. The boron trihalide complexes with a number of phosphine sulphides and selenides can be isolated for the chloride, bromide, or iodide but, consistent with its reduced Lewis acidity, the trifluoride does not react.600Alkyldithiophosphonir, acids give tin, lead, and mercury derivatives such as Me,SnSP(S)FEt, Pb[SP(S)FMe],, and MeHgSP(S)FMe, which are monomeric in solution, and there is n.m.r. evidence for a bidentate phosphonate group in the tin compound.6o1 Vanadyl chelates of alkoxy-ethyl and alkoxy-phenyldithiophosphonates (87) have been synthesized and e.s.r. measurements
(87) R‘= Et or Ph, RZ= Me, Et, Pr, etc.
carried out? while magnetic measurements together with i.r. and electronic spectra are reported for vanadyl and uranyl complexes of a number of substituted diaryldithiophosphinic G.1.c. on a glass microbead column is a useful separation method for metal dialkyldithiophosphates.604 An X-ray structure of one of the monoclinic modifications of tin hexathiohypodiphosphate, Sn,P,S,, shows P& groups with close to 3m symmetry connected into a three-dimensional net by tin The P-P distance is 2.202 A and P-S distances range between 2.015 and 2.035 A. The thiophosphates Na3POS3and NaBaP0,S,8H20 are isotypic with the corresponding thioarsenates.606 The red phosphorus-P,Se3 system has been examined and the selenide shown to exist in three allotropic Insertion of selenium into the P-P bond of (CF3)2PP(CF3)2 occurs on heating at 100°C but reactions of 597 598
599
E. Fluck, G. Gonzalez, and H. Binder, 2.anorg. Chem., 1974, 406, 161. B. A. Khaskin, N. N. Mel’nikov, and N. A. Torgasheva, J. Gen. Chem. (U.S.S.R.), 1973, 43, 1901. B. A. Khaskin, N. A. Torgasheva, and N. N. Mel’nikov, J. Gen. Chem. (U.S.S.R.), 1973, 43,
2065. ‘00
602
603
‘04
‘06
607
P. M. Boorman and D. Potts, Canad. J. Chem., 1974, 52, 2016. H. W. Roesky, M. Dietl, and A. H. Norbury, Z. Naturforsch., 1973, 28b, 707. D. R. Lorenz, D. K. Johnson, H. J. Stoklosa, and J. R. Wasson, J. Inorg. Nuclear Chem., 1974, 36, 1184. R. N. Mukherjee, S. V. Shanbhag, M. S. Venkateshan, and M. D. Zingde, lndian J. Chem., 1974, 11, 1066. T. J. Cardwell and P. S. McDonough, Inorg. Nuclear Chem. Letters, 1974, 10, 283. G. Dittmar and H. Schafer, 2. Naturforsch., 1974, 29b, 312. M. Palazzi, Bull. SOC.chim. France, 1974, 42. Y. Monteil and H. Vincent, Canad. J . Chem., 1974, 52, 2190.
384
Inorganic Chemistry of the Main-group EZements the product [(CF,),P],Se with hydrogen chloride and the halogens, etc. give known phosphorus compounds with separation of selenium.6o8New phosphorus selenides RP(Se)F2 and RP(Se)FCI can be prepared by fluorination of the corresponding chlorides,60" and the monoselenophosp hinic acid Bu'PhP(Se)OH has been prepared by two independent routes and resolved into optical antipodes.610Two series of products, i.e. the isomeric thiono(selenolo) and thiolo(se1enono) derivatives, which are separable by column chromatography, result from reactions between potassium 00-diphenylphosphoroselenothioate and alkyl chloromethyl sulphides.61' Few instances of hydrogen bonding to selenium or tellurium are known, but this is indicated by shifts in the OH stretching mode of phenol in the presence of, for example, Bu,PSe or (Me,N),PTe."l2 1.r. spectra have been reported for metal complexes incorporating Ph,P(Se)Se, Ph,P(S)S, PhzP(Se)S,6'3and (PhO),P(Se)S ligand~.~'"
3 Arsenic Arsenic and Arsenides.-Appearance potentials for the negative ions As-, As;, and As;, formed from As, by dissociative resonance capture, have been measured, giving values of the standard heats of formation."' New ternary arsenides, including RhMAs (M=Ti, V, Cr, Fe, or Ni), RuMAs (M = Mn or Cr), and PdMAs (M =Ti or Cr), have been prepared from elemental mixtures heated at 700-85O0C, and they have been assigned to structural types.616 Continuous phase transitions for CrAs, CoAs, and Mno.,Feo.lAsbetween the closely related MnP and NiAs structures have been detected by X-ray diffraction over an extended temperature range,617 and for the latter compound the transformation is either a second- or higher-order process.618The compounds CoM,, RIM3, and IrM3, where M = A s or Sb, belong to the skuttesudite structure type, and these new X-ray data have been compared with those for the isostructural p h o ~ p h i d e s .The ~ ~ ~absence of Zn-Zn bonds in the crystal structure of ZnAs, is notable, as these were expected, on the basis of the presumed 608
R. C. Dobbie and M. J. Hopkinson, J . Fluorine Chem., 1973, 3, 367. H. W. Roesky and W. Kloker, Z. Naturforsch., 1973, 28b, 697. 'lo B. Krawiecka, Z. Skrzypczyfiski, and J. Michalski, Phosphorus, 1973, 3, 177. 6 1 1 N. M. Vatamanyuk, V. V. Turkevich, N . 1. Gritsai, and A. P. Vas'kov, J. Gen. Chem. (U.S.S.R.),1973, 43, 1697. 612 R. R. Shagidullin, I. P. Lipatova, I. A. Nuretdinov, and S. A. Samartseva, Doklady Chem., 1973, 211, 694. '13 A. Miiller, V. V . Krishna Rao, and P. Christophliemk, J . Inorg. Nuclear Chern., 1974, 36, 474. 'I4 I. M. Cherernisina, L. A. Il'ina, and S. V, Larionov, Russ. J. Inorg. Chem., 1973, 18, 675. 6 1 5 S. L. Bennett, J. L. Margrave. J. L. Franklin, and J. E. Hudson, b. Chem. Phys., 1973, 59, 5814. 616 B. Deyris, J . Roy-Montreuil, A. Rouault, A. Krumbugel-Nylund, J.-P. Shateur, R. Fruchart, and A. Michel, Compt. rend., 1974, 278, C, 237. 6'7 K. Selte and A. Kjekshus, Acta Chem. Scand., 1973,'27, 3195. K. Selte, A. Kjekshus, and A. F. Andresen, Acta Chem. Scand., 1973, 27, 3607. 6'9 A. Kjekshus and T. Rakke, Acta Chem. Scand. (A), 1974, 28, 99. '09
Elements of Group V
385
isomorphism with ZnP2.620 The structure contains two types of zinc and four types of arsenic sites, but all involve tetrahedral co-ordination. A new cationic complex containing Hg-As bonds has been synthesized following equation (21). The products with X =NO;, PF;, or BF, are stable MeHgX
+ 3MeHgOBu‘ + ASH,
-+
+
[As(HgMe),]X
3Bu‘OH (21)
in air and probably have a tetrahedral structure.621 Low yields of Ag(HgMe), could be obtained by modifying the conditions but it was not possible to obtain the antimony analogues.
Bonds to Carbon.-A novel cyclo-triarsane derivative (88), in which the substituents are constrained into all cis positions, can be obtained by Me
I
/c\
CH,
\
I A+A~
CH,
CH21
‘As/
(88)
heating MeC(CH2As12),with sodium in THF.622Some 7 5 An.q.r. ~ measurements are in good agreement with the known structures of (PhAS), and (C6F,As)6,623 while for (89) and (90), of unknown structures, the results point to the presence of a diad axis in the former and the possibility of three different forms for (90) depending on the crystallization method. A ladder Ph- As- As-Ph
I
I
CF,-CC--L-CF,
FC
AS-AS-C6F,
6 - ~
I
F,C-C=C-CF,
polymer of high molecular weight that has recently been synthesized has semiconductor properties, and it is based on the stacking of MeAs-AsMe Preparation is either by HI elimination from mixtures of MeAsHz and MeAsI, or by cleavage of ( M ~ A Swith ) ~ a trace of MeAsC1,. A series of monocyclopentadienyl-arsines (91) with fluxional u -bonded structures can be prepared from halogeno-arsines and either cyclopentadienyltrimethylsilane or lithium ~yclopentadienide.~~’ Vibrational spectra of (PhCH,),MX,, where M = A s or Sb and X = F or C1, are in accord with 620 621
622 623 624
625
M. E. Fleet, Acta Cryst., 1974, B30, 122. D. Breitinger and G. P. Arnold, Inorg. Nuclear Chem. Letters, 1974, 10, 517. J. Ellermann and H. Schossner, Angew. Chem. Intenat. Edn., 1974, 13, 601. T. J. Bastow and P. S. Elmes, Austral. J. Chem., 1974, 27, 413. A . L. Rheingold, J. E. Lewis, and J. M. Bellama, Inorg. Chem., 1973, 12, 2845. P. Jutzi and M. Kuhn, Chem. Ber., 1974, 107, 1228.
386
Inorganic Chemistry of the Main- group Elements
R'
(91) R '
= R'= F, CI, Br, or
Me
slightly distorted trigonal-bipyrarnidal structures,626and i.r. and Raman data for Me,As, obtained by a low-temperature reaction between Me,AsCl, and methyl-lithium, have also been interpreted on the basis of trigonal-bipyramidal ge~metry.~"Similar data for Ph,As and Ph,Sb indicate that the solid-state structures, i.e. trigonal-bipyramidal and square-pyramidal respectively, are retained in
Bonds to Halogens.-Reactions between AsF, and the negative ions formed mass spectrometrically lead to AsF; as the predominant secondary ion, whereas in AsF,, both AsF; and AsF; are formed.629A series of new fluoroarsinic acid esters F,As(OR),+,, with n = 1 or 2 and R = methyl to hexyl, result from either alcoholysis of the trifluoride or redistribution reactions between mixtures of the trifluoride and trialkoxide .630 The product identities were confirmed by "F and 'H n.m.r. spectroscopy. An accurate redetermination of the structure of KAsF, confirms the space group as R; and shows a nearly perfect octahedron of fluorine atoms about arsenic (As-F 1.72 A)."' Anions with C, symmetry are found in the structures of the isomorphous compounds Rb,(As,F,,O),H, 0 and K,(As,F,,O),H,O;6" bonds to the bridging oxygen are 1.77 and 1.72 A and the AsOAs angle is 136.5". In the doubly oxygen bridged anion [As2F,02]*-, on the other hand, the structure is centrosymmetric, with D,, symmetry. Structural parameters, shown in Figure 13, point to the shortness of the As * * As distance and the 96" angles at the bridging oxygen atoms as being significant The hexafluoroarsenate ion is well known as stabilizing unusual cations, and in the period covered in this Report the following compounds have been investigated: NF,'AsF; (thermal decomposition),hi OSF,Cl+AsF, (preparacrystal s t r u c t ~ r e ~0SF:AsF; ~~), tion, also PF;, SbK, and Sb,F;, (crystal ~tructure),6~' C1F;AsF; (vibrational data),h38ClOF,'AsF; (preparation and vibrational data, also Sb, Bi, V, Nb, and Ta analogues),639K r F *
"' L. Vernonck
and G. P. van der Kelen, Spectrochirii. Acta, 1973, 29A, 1675.
''' K.-H. Mitschke and H. Schmidbaur, Chem. Ber.. 1973, 106, 3645. "' G. L. Kok, Spectrochim. Acta, 1974. M A , 961. '*'
63"
631
632 633 634
63s 636
h37 63'
639
T. C. Rhyne and J. G. Dillard, Inorg. Chem., 1974, 13, 322. F. Kober and W. J. Ruhl, J. Fluorine Chem., 1974, 4, 65. G. Gafner and G. J. Kruger, Acta Cryst., 1974, B30, 250. W. Haase, Acta Cryst., 1974, B30, 1722. W. Haasc, Chem. Ber., 1974, 107, 1009. 1. J. Solomons, J. N . Keith, and A. Snelson, J. Fluorine Chern., 1972. 2, 129. C . Lau and J. Passmore, J.C.S. Dalton, 1973, 2528. R. F. Dunphy, C . Lau, and J. Passmore, J.C.S. Dalton, 1973, 2533. C.Lau, H. Lynton, J. Passmore, and P.-Y. S e w , J.C.S. Dalton, 1973, 2535. K. 0. Christe and W. Sawodny, Inorg. Chem., 1973, 12, 2879. R. Bougon, T. Bui Huy, A. Cadet, P. Charpin, and R. Rousson, Inorg. Chem., 1974,13, 690.
Elements of Group V
387
Figure 13 The structure of the [As2F8O2]2-ion in CsAszFsO;! (Reproduced by permission from Chem. Ber., 1974, 107, 1009) AsFi, Kr,FSAsF; ("F n.m.r. and Raman spectra, also SbF; XeFAsF;, Xe,SAsF$ (Raman [(FXe),SO3F]'AsF$ (preparation, "F n.m.r. and Raman spectra).642 In addition to these, Gillespie and his co-workers have produced two new mercury cations by oxidation of the element with either AsF, or SbF, in liquid sulphur dioxide. The formulae ~;~~ results are Hgs(AsF,), or Hgs(SbzFI1)2643 and H & ( A s F ~ )crystallographic are available for each. During the initial stages of these oxidation reactions, the mercury is converted into a golden mass, which by crystallography can be formulated as Hg2.86AsF6.645 The structure consists of an array of octahedral AsF; ions with the fluorine atoms occupying three quartets of the points of a cubic-close-packed lattice, together with infinite chains of mercury atoms with bonds shorter than those in the metal running along the a and b directions. A fluorosulphate ion transfer to AsF, occurs with chloryl fluorosulphate, giving C102[AsF,(S03F)],but an analogous antimony compound could not be prepared.646In this case the product was a mixture of C1O2(Sb2F,,)and SbF, (S0,F). The preparation of 1: 1 complexes of arsenic, antimony, and bismuth trihalides with dithio-oxamides has been r e p ~ r t e d . ~1.r. ~ ' spectra of the arsenic compounds point strongly to the probability of dimeric, octahedral structures, but with the two heavier Group V elements square-pyramidal structures have been suggested. Crystalline adducts 2MBr3,3dioxan, where 640 641
642 643
644 645
646 647
R. J. Gillespie and G. J. Schrobilgen, J.C.S. Chem. Comrn., 1974, 90. R. J. Gillespie and B. Landa, Inorg. Chem., 1974, 13, 1383. R.J. Gillespie and G. J. Schrobilgen, Inorg. Chem., 1974, 13, 1694. B. D. Cutforth, C. G. Davies, R. A. W. Dean, R. J. Gillespie, P. R. Ireland, and P. K. Ummat, Inorg. Chem., 1974, 13, 1343. B. D. Cutforth, R. J. Gillespie, and P. R. Ireland, J.C.S. Chem. Comm., 1973, 723. I. D. Brown, B. D. Cutforth, C. G . Davies, R. J. Gillespie, P. R. Ireland, and J. E. Vekris, Canad. J . Chem., 1974, 52, 791. P. A . Yeats and F. Aubke, J . Fluorine Chem., 1974, 4, 243. G. Peyronel, A . C. Fabretti, and G. C. Pellacini, Spectrochim. Acta, 1974, 30A, 1723.
388 Inorganic Chemistry of the Main -group Elements M = A s , Sb, or Bi, can be isolated, but cryoscopy indicates their complete dissociation in Solubility data for arsenic, antimony, and bismuth tribromides show regular solution behaviour in a number of organic absorption spectra of the corresponding iodides in the solid state have been ~ b t a i n e d . ~ " Refinement of the As-AsI, region of the arsenic-iodine diagram65'does not show the formation of AsJ, as was suggested by previous investigators. Bonds to Nitrogen.-An extensive series of bis(dimethy1arsino)amines RN(AsMe,), can be prepared from chloro- or iodo-dimethylarsine and the appropriate primary amine.652The As-N bonds in such compounds are markedly sensitive to protonic reagents, e.g. hydrogen halides, alcohols, thiols, but with tris(dimethy1amino)arsine this serves as a convenient route to a large number of esters and thi0este1-s.~~~ With Me,AsNMe,, 172-diols and with can give both mono- and di-esters depending on the mole hydroxymethylf errocene the product is CpFeC5H4CH~OAsMe2.6s5 An analogous di-ferrocene product is obtained with MeAs(NMe,),. Other secondary amine derivatives result from transamination reactions with Me2NAsF,, and the operation of steric and mechanistic effects in these systems has been c o n ~ i d e r e d . ~Transamination '~ with primary amines is not as clear-cut, and polymeric species, probably of the form (RN=AsF),, are the products. Ammonolysis of chlorodimethylarsine gives the substituted ammonium chloride [Me,AsNH,]Cl, while in admixture with chloramine the product has the empirical formula Me4As2N2HCL6"The latter also results if tetramethyldiarsine is the starting material. Corresponding reactions of EtzAsCl with ammonia and chloramine give (Et,As),N and Et,As,N,HCl, respectively, while with tetraphenyldiarsine, chloramination produces the hydrochloride of the trimeric arsazene, (Ph,AsN),,HCl. Mass spectral data for all the compounds have been discussed and the results of a single-crystal structure determination on (Ph,AsN), also reported. The As,N, ring is slightly puckered but all the As-N distances are equal (1.758 A). Methoxy derivatives of such arsenic-nitrogen cyclic systems, which are analogues of the better known cyclo-phosphazenes, have been obtained from the decomposition of NH4[As(OMe),]."'" The bulk of the product by mass spectrometric analysis is the trimer, but [AsN(OM~)~],, can also be detected. 6JH
R. C . Mahebhwari, S. K. Suri, and V. Ramakrishna, lndian J. Chem.. 1973. 11, 1196. R. C. Maheshwari, S . K. Suri, and V. Ramakrishna, J . Inorg. Nuclear Chem., 1974, 36, 1809. B. Mishra and V. Ramakrishna, Indian J. Chem., 1973. 11, 790. A. P. Chernov, S. A. Dembovskii, and A. F. Borisenkova, Russ. J. Inorg. Chem., 1973, 18, 1530. 652 F. Koher, Z . anorg. Chern., 1973, 301, 243. "' F. Kober and W. J. Ruhl, Z . anorg. Chem.. 1974, 403, 56. "' F. Kober and W. J. Riihl, Z . anorg. Chem., 1974, 406, 52. 6 s 5 F. Kober, Z . Naturforsch., 1974, 29b, 358. 656 F. Kober and 0. Adler, J. Fluorine Chem., 1974, 4, 73. 657 L. K. Krannich, U. Thewalt, W. J. Cook, S. R. Jain, and H. H. Sisler, Inorg. Chem., 1973, 12, 2304. H. Preiss and D. Hass, Z . anorg. Chem., 1974, 404, 190. h4y hS0
Elements of Group V 389 Bonds to Oxygen.-Alcohol groups can be displaced from triethoxyarsine by oximes or diethylhydroxylamine in a stepwise manner to give the Two new 1,3,2-dioxa-arsolans (92) products (EtO)3-nAs(ON=CR1Rz),,.659 result when tris(dimethy1amino)arsine and either ethylene glycol or pinacol react, and further reaction of these compounds with a -hydroxy-acids leads
0
Me
NCA,
R1,
As-OCR'R'COO-
I
H2kMe2
R"co ''
(94) R = C l , X = O o r S
R=Ph,X=OorS
(93)
to displacement of both the glycol and amine group, giving (93).'" Detailed analysis of the proton spectra of similar cyclic arsenates (94) leads to coupling-constant and chemical-shift data661and shows the presence of both cis- and trans -isomers. Ring opening in oxathioarsolans ( 9 3 , noted here for
the first time, can be brought about by monothioglycol, giving PhAs(SCH2CHzOH)z.66z This compound can also be prepared from PhAs(OMe), and the thioglycol following the general method in equation (22).'" R',As(XR*),.., R' = Et or Ph X = O or S R' = Me or Et
+
( 3 - n)HSCH2CH20H
--+
(3 - n)R'XH
+
R',As(SCH,CH,OH),_,
(22)
Complex formation between arsenic or antimony(m) oxide and selenium trioxide gives the adducts Mz0,,3Se0, but the corresponding pentoxides do R. C. Mehrotra, A. K. Rai, and R. Bohra, Synth. React. Inorg. Metal-Org. Chem., 1974, 4, 167. P. Maroni, Y. Madaule, and J.-G. Wolf, Compt. rend., 1974, 278, C, 191. 6 6 1 D. W. Aksnes and 0. Vikane, Acta Chem. Scand., 1973, 27, 2135. 662 N. A . Chadaeva, K. A. Mamakov, and G. Kh. Kamai, J . Gen. Chem. (U.S.S.R.), 1973, 43, 821. 663 N. A . Chadaeva, K. A. Mamakov, R. R. Shagidullin, and G. Kh. Kamai, J . Gen. Chem. (U.S.S.R.), 1973, 43, 825. 65y
3 90
Inorganic Chemistry of the Main-group Elements
not The arsenic(II1) complex forms a conducting solution in fluorosulphuric acid which may contain the solvated AsO' ion, but a polymeric structure (96) is considered more likely for the species in the
(96)
solid state. For the antimony compound the formula is given as Sb,(SeO,),. Kinetic studies have been carried out on the oxidation of arsenic(rI1) by Tl"' in perchloric and by CrVx.665b Attempts to prepare alkoxyarsonium salts such as [Ph,AsOCH,C(O)OR]X from triphenylarsine oxide and either halogenoacetic esters, chloroacetone, or chloroacetonitrile gave only (Ph3AsOH)X for X = C1 or Br and (Ph,AsO)?HI when iodides were used.""" Mass spectrometric measurements on As(OMe),, OAs(OMe),, As(OMe),, and a variety of similar species generally show a molecular ion of low intensity, which fragments by a simple cleavage reaction.667Further details of the fragmentation have been discussed. The presence of a four-membered ring (97) in compounds
(97)
with the formula A s , O ( O M ~ ) ~ N is R indicated by 'H n.m.r. and massspectrometric data.""" Detailed vibrational spectra and normal-co-ordinate analyses are now available for M~,As(O)OH,~"'~"~" MeAs(O)(OH),,""' MeAsO:-,""' M ~ A S ( O ) ( O M ~ ) , , ~ ~Me,As(O)(OMe),"" '~~" and (Me0)3As0,671 etc. Spirocyclic structures (98) have been assigned to the esters produced from glycols and aryl- or alkyl-arsonic 664
R. C. Paul, R. D. Sharma, S. Singh, and K. C . Malhotra, Indian J. Chem., 1973, 11, 1174.
"' ( a ) P. D. Sharma and Y . K. Gupta, Austral. J. Chem., 1973, 26, 2115; ( b ) K. K. Sen Supta h6h 667 h68 669 670
671 672
and J. K. Chakladar, J.C.S. Dalton, 1974, 222. B. E. Abalonin, Yu. F. Gatilov, and Z . M. Izrnailov, J. Gen. Chem. (U.S.S.R.),1974, 44, 145. H. Preiss, Z . anorg. Chem., 1974, 404, 175. H. Preiss and H. Jancke, 2. anorg. Chem., 1974, 404, 199. H.-V. Grundler, H.-D. Schumann, and E. Steger, J. Mol. Structure, 1974, 21, 149. F. K. Vansant, B. J. van der Veken, and M. A. Kerrnan, Spectrochim. Acta, 1974, 30A, 69. F. K. Vansant and B. J. van der Veken, J. Mol. Structure, 1974, 22, 273. V. S. Garnayurova, V. V. Kuz'rnin, B. D. Chernokal'skii, and R. R. Shagidullin, J. Gen. Chem. (U.S.S.R.),1973. 43, 1921.
Elements of Group V
391
Oxygen exchange between arsenate and water is dependent on pH, with the reaction is an overall activation energy of 13.2 kcal mol-' at pH 7.51 catalysed by arsenious acid, probably through rapid condensation of AS"' and As" species to give an anion of mixed oxidation state such as H,AszO;.673b Exchange of oxygen between Na2HAs0, and NaH,AsO, and crystal water has also been examined during hydration and dehydration Only one compound, NaMAs04,9H20, occurs in the Na,AsO,-M,(As04),-H20 system, where M = Sr or Ba;674ain the corresponding potassium arsenate systems the products are KMAs0,,8H20 but when M = C a , both octa- and hepta-hydrates are formed.674bX-Ray data have been reported for C ~ , ( H A S O ~ ) ~ ( A S O ~ ()g~~, t~rH i n~i tOe ) ~ and ~ ' compounds in the series N ~ , M H , - , ( A s O ~ ) ~ , ~ H where ~ O , M = A1 or Fe and 0.6 < x < 2.h76Solid phases produced in the Na,0-M20,-As,05-H20 system with M = Al or Fe depend on the exact preparative method used, and species such as NaAlH,(AsO,),,H,O, NasA1,H7(As0,)6,2H20, and N ~ , A I ~ ( A s O , )etc. ~ , result in the aluminium case .677 A series of stoicheiometric dihydrated orthoarsenates, i.e. MAs04,2H20 and a new where M = A l , Ga, Cry or Fe, with the scordite where M = Fe or Cr, have been described.679 family of arsenates M2As401Z, The latter result by heating M(H,As04),nH,0 to 800 "C and are considered to contain arsenic in both the +3 and +5 oxidation states. Their formulation as FeAs(AsO,),, for example, is supported by the isolation of an isotypic phosphor us compound Fe,AsP, 012, which is an orthophospha te. Dehydration of lanthanide arsenates LnAs04,2Hz0occurs at 140 "C to give amorphous materials, which crystallize on further heating in the range 400-500"C.680 Details of the preparation and i.r. and 'H n.m.r. spectra have been published for the following scandium arsenates: Sc(As0,),2H20, S C ( H ~ A ~ O ~ ) ~Sc,(H,As,O,),, ,~H~O, and SC(ASO,),,~~~ and the principal force 673
( a ) A. Okumura and N. Okazaki, Bull. Chem. SOC.Japan. 1973, 46, 2937; ( b ) A. Okumura, N. Yamamoto, and N. Okazaki, ibid., p. 3633; (c) A. Okumura and N. Okazaki, ibid., p.
2981. (a) N. Ariguib-Kbir, R. Stahl-Brasse, and H. GuCrin, Bull. SOC.chim. France, 1974, 1221; ( b ) N. Ariguib-Kbir, R. Stahl-Brasse, and H. GuCrin, Cornpt. rend., 1974, 278, C,339. M. Catti and G. Ferraris, Acta Cryst., 1974, B30, 1789. 616 F. d'Yvoire and M. Screpel, Bull. SOC.chim. France, 1974, 1211. 677 M. Screpel, F. d'Yvoire, and H. GuCrin, Bull. SOC. chim. France, 1974, 1207. 678 M. Ronis and F. d'Yvoire, Bull. SOC. chim. France, 1974, 78. 679 F. d'Yvoire, M. Ronis, and H. GuCrin, Bull. SOC.chim. France, 1974, 1215. 680 L. E. Angapova and V. V. Serebrennikov, Russ. J. Inorg. Chem., 1973, 18, 901. L. N. Komissarova, G. Ya. Pushkina, I. V. P. Khrameeva, and E. G. Teterin, Russ. J. Inorg. Chem., 1973, 18, 1225.
674
67s
392 Inorganic Chemistry of the Main-group Elements constants for the As,O;- ion have been estimated from the i.r. and Raman spectra of Sr,As,07 and Ba2As20,.682 Close similarity to the olivine structure is revealed by an X-ray study on C o 7 0 A ~ 3 6 0one 1 6 7of the compounds formed in the CoO-As,Os system.6R' The oxygen atoms are in hexagonal close packing, with the cobalt and arsenic occupying respectively the octahedral and tetrahedral sites. Complete occupancy of each site would lead to the composition Co8As4OI6. The regions of stability with respect to acid for the molybdo-arsenic heteropolyanions have been defined684and two new series of such acids with Mo :As ratios of 3 : 1, i.e. AszMo60:; and As,Mo,~O~;,have been isolated and fully identified.68s Bonds to Sulphur or Selenium.- Arsenic, antimony, and bismuth trichlorides react with bis(2-mercaptoethyl) sulphide, liberating hydrogen chloride and forming the cyclic compounds (99).'" Complete spectroscopic data
/
CH2--CHI-S
\
S'
\('H
2-C'H
2-S
have been measured for the and structures determined for the arsenic688and antimony ones.689In each case the eight-membered ring has a S interactions distorted boat conformation with strong transannular M (2.72 and 2.83 A, respectively, for M =As or Sb). In this way a pseudotrigonal-bipyramidal arrangement around the Group V element is achieved. Vibrational assignments from i.r. and Raman data have been proposed for and for Me,AsS and Me,AsSe.6y1 *
*
-
's-s' Arsenic tris(dialky1dithiocarbamates) show a wide range of 7 5 An.q.r. ~ signals merely on changing the alkyl group and, as all the compounds E. J . Baran, J. C. Pedregosa, and P. J. Aymonino, J. Mol. Structure, 1974, 22, 377. N. Krishnamachari and C. Calvo, Canad. J. Chem.. 1974, 52, 46. h84 R. Contant, B d l . SOC.chim. France, 1973, 3277. P. Souchay and R. Contant, Bull. SOC. chim. France, 1973, 3287. "' R. Engler, Z. anorg. Chem., 1974, 406, 74. '*' R. Engler, Z . anorg. Chem., 1974, 407, 35. M. Drager, Chem. Ber., 1974, 107, 2601. '*') M. Drager and R. Engler, Z . anorg. Chem., 1974, 405, 183. 69" K . Volka, P. Adamek, H. Schulze, and H. J. Barber, J. Mol. Structure, 1974, 21, 457. "" F. L. Kolar, R. A . Zingaro, and J. Laane, J. Mol. Structure, 1973, 18, 319. h82 hX3
Elements of Group V
393
contain arsenic in six-fold co-ordination, the changes are attributed to changes in the SASS angle.692The mass spectrometric behaviour of these compounds and the antimony and bismuth analogues has been and Manoussakis et al. have obtained the corresponding diselenocarbamate complexes from the reaction of the trichloride with a secondary amine and carbon diselenide .694 The thioarsinic acids [Ph,AsOS]H, [(PhCH2)2AsOS]H, and [(PhCH2)2AsS2]H have been described for the first time and used as ligands with transition Hydrogen sulphide at 400 "C converts lanthanide arsenates into trithioarsenates (AsOS:-) for the earlier lanthanides but to the dithio-analogues (AsO,S:-) with the elements from europium to lutetium.696 The compound Pb2&1& (jordanite) has a distorted PbS-type structure, with trigonal-pyramidal co-ordination by sulphur about the arsenic.697 The structure of As4Se4 is similar to that of realgar, with a square of selenium atoms bisecting a distorted tetrahedron of arsenic Princi2.384(5); As-As pal parameters of this cage molecule are: As-Se 2.566(8)A; LAsSeAs 98.1(3)"; LSeAsSe 94.2(3)".
4 Antimony Antimony and Antimonides.- Antimony metal and lithium nitride react at 430 "C to give a new binary compound Li,Sb, which is isotypic with Fe,P.699 Ca,Sb and Ca,Bi are i ~ o t y p i c and , ~ ~full structure determinations have been carried out on c~-Mg,Sb,,~~' Ca5Sb3,702and Sr5Sb,.703In the latter the structural unit is the SbSr, unit, in which the strontium atoms are arranged at the corners of a very distorted tetrakaidecahedron. X-Ray data suggest filled NiAs structures for the new compounds CaCuSb, SrCuSb, and their bismuth analogues, which are prepared from the elements at 1400 "C.'" Sharpening of I2'Sb Mossbauer spectra can be achieved in some cases by Fourier-transform methods, and this approach has been tested on data for CoSb, and Feo5Nio,5Sb3.705 Bonds to Carbon or Nitrogen.- The preparation of dialkoxy- and diphenoxy-stibines from methyldibromostibine and the sodium salts of 692 h93
694 695
696 697 698
699 700 7"1
702
' 0 3 704 '05
T. J. Bastow and H. J. Whitfield, J . Inorg. Nuclear Chem., 1974, 36, 97. G. E. Manoussakis, E. D. Micromastoras, and C. A. Tsipis, Z. anorg. Chem., 1974,403, 87. G. E. Manoussakis, C. A. Tsipis, and A. G. Christophides, Inorg. Chem., 1973, 12, 3015. A. Muller, P. Werle, P. Christophliemk, and I. Tossidis, Chem. Ber., 1973, 106, 3601. L. E. Angapova and V. V. Serebrennikov, Russ.J. Inorg. Chem., 1973, 18, 1213. T. Ito and W. Nowacki, Z. Krist., 1974, 139, 161. P. Goldstein and A. Paton, Acta Cryst., 1974, B30, 915. R. GCrardin and J. Aubry, Compt. rend., 1974, 278, C, 1097. B. Eisenmann and H. Schafer, Z. Naturforsch., 1974, 29b, 13. M. Martinez-Ripoll, A. Haase, and G. Brauer, Acta Cryst., 1974, B30, 2006. M. Martinez-Rip11 and G. Brauer, Acta Crysf., 1974, B30, 1083. M. Martinez-Ripoll and G. Brauer, Acta Cryst., 1973, B29, 2717. B. Eisenmann, G. Cordier, and H. Schafer, Z. Naturforsch., 1974, 29b, 457. A. Kjekshus and D. G. Nicholson, Acta Chem. Scand. (A), 1974, 28, 469.
3 94
Inorganic Chemistry of the Main -group Elements alcohols or phenols proceeds readily;706 the diethoxy-derivative proved useful as a starting material for ligand-exchange reactions with thiols, 1,2-diols, and 1,2-dithiols. An investigation of the structure of Ph,SbOSbPh, is of interest as Mossbauer data show two antimony peaks, but recent X-ray results show the presence of only one kind of antimony atom.'" The Sb-0 and Sb-C distances are 1.97 and 2.15 A, respectively, and as the CSbC and CSbO angles are only slightly greater than 90" it is concluded that the antimony lone pairs are accommodated in the s-orbitals. Mossbauer data at 80 K have been reported for compounds with the following formulae: R3SbX2, R,SbX,, R,SbX, and R,Sb.7"8 Organometallic reagents show promise as extractants for halogens, in particular fluorine, and a range of some 16 antimony derivatives has been Two distinct paths are followed in the decomposition of bisin~estigated.~'~ (tripheny1bromo)antimonyl peroxide, P h,BrS bOOSbBrPh,, in chloro benzene at 45 "C;"" the first involves liberation of oxygen and formation of Ph,BrSbOSbBrPh, but in the second, following heterolytic cleavage of the peroxy linkage, there is transfer of a phenyl group from antimony to oxygen. Five-co-ordination to both antimony atoms is found in the structure of the oxygen-bridged compound (Ph,SbN3)20,711 but in (Ph,Sb),CO, there is antimony in both five- and six-fold c o - ~ r d i n a t i o n .In ~ ~ the ~ azide, the bridging oxygen atom and the azido-group occupy axial positions in a slightly distorted trigonal-bipyramidal arrangement. The Sb-0 distance is 1.985(3) A and the bridge angle is 139.8(4)". In the second structure, shown in Figure 14, the carbonate group is bidentate to one antimony atom (Sb-0 2.185 and 2.325 A), giving an octahedral arrangement, and unidentate to the second atom (Sb-0 2.257 A). An octahedral arrangement with trans methyl groups has been found for dimethyldibromo(acety1acetonato)antim~ny(v).~ The l ~ unusual square-pyramidal geometry of Ph,Sb is not found for the penta-p-tolyl analogue.?14In this case, the structure is the more usual trigonal bipyramid, but it is distorted, particularly at the equatorial CSbC angles. Two of these, 113" and 130", are markedly different from the expected 120" angles, suggesting that packing forces play an important role in determining the ground-state structure of solid R,Sb compounds. 706
707 708
7OY
"" 711
713 714
N. Baumann and M. Wieber, Z. anorg. Chem.. 1974, 408, 261. J. Bordner, B. C. Andrews, and G. G . Long, Cryst. Struct. Comm., 1974, 3, 53. S. E. Gukasyan, V. P. Gor'kov, P. N. Zaikin, and V. S. Shpinel, J . Struct. Chem. (U.S.S.R.), 1973, 14, 603. M. Benmalek, H. Chermette, C . Martelet, D. Sandino, and J. Tousset, J . Inorg. Nuclear Chem., 1974, 36, 1359, 1365. J. Dahlmann and K. Winsel, Z. Chem., 1974, 14, 232. G. Ferguson and D. R . Ridley, Acta Cryst., 1973, B29, 2221. G. Ferguson and D. M. Hawley, Acta Cryst., 1974, B30, 103. S. Uda, Y. Kai, N . Yasuoka, and N. Kasai, Cryst. Struct. Comm., 1974, 3, 257. C. Brabant, J. Hubert, and A. L. Beauchamp, Canad. J. Chem., 1973, 51, 2952.
395
Elements of Group V
n
Figure 14 The structure of (Ph4Sb)2C03 (Reproduced by permission from Acta Cryst., 1974, B30, 103) Thermal or photochemical methods can be used to prepare metal carbony1 complexes from Sb(NMe,),;71swith the Group VI hexacarbonyls, the products are formulated as Sb(NMe,),,M(CO),.
Bonds to Halogens.-Antimony (111) Compounds. Aqueous solutions of antimony(II1) fluoride give only one I9F n.m.r. signal, whose shift decreases with increasing con~enfration.’~~ Addition of either NH,F or KF causes a downfield shift, which reaches a minimum at a 1:l mole ratio, thus providing unambiguous evidence for the formation of the SbF; ion. The structure of the new antimony fluoride, Sb,,F,, or 6SbF,,SSbF,, which can be prepared by direct fluorination of the element, has a unit cell containing ’I5 716
A. Kiennernann and R. Kieffer, Compt. rend., 1974, 279, C, 355. Yu. A. Buslaev and V. V. Peshkov, Russ. J. Inorg. Chem., 1973, 18, 803.
396 Inorganic Chemistry of the Main - group Elements five SbFi anions and a section of a polymeric chain cation, Sb,F,,5+.717 Separate SbF: and Sb2F: units can be distinguished in the cation, and in the latter there is a linear fluorine bridge between the SbF, and SbF, units. X-Ray diffraction and vibrational data have been reported for a series of l9 antimonate(111) salts. te trafluoro -718 and pentafl~oro-~ Antimony(II1) halides form addition compounds with potassium ferrocyanide, either in the melt or in sulphur dioxide solution, to which the formulae K,[Fe(CNSbX,),] for X = F or C1 or &[Fe(CNSbX,),(CN),], for X=C1 or Br, are given.72oMossbauer data for a number of antimony(111) species show large quadrupole splittings, associated with stereochemical activity of the 5s electrons, only for SbFi, SbCl;, and SbzF;-.”’ New vapour-pressure data for antimony trichloride in the 360-428 K temperature range lead to the log(p/a tm) = (4.07 f0.64) - (2 183 f80)K/ T Weak complex formation between the trichloride or tribromide and hydrocarbons, ethers, or ketones causes little change in the electron distribution around the antimony atoms according to a Mossbauer inve~tigation.’~~ Stronger complexes, i.e. SbX3,2L and BiX3,3L, are formed, for X = C1 or Br and L = tetramethylene sulphoxide, which from vibrational data have respectively square-pyramidal and octahedral co-ordination around the Group V atom.72A The extent of interaction between SbCl, and acetonitrile has been assessed from the splitting of the v(C-N) band, which is interpreted in terms of the existence of both donor-acceptor and dipole-dipole complexes.725The formation of an SbC1,-cis -stilbene adduct is apparently important in the antimony-trichloride-inducedphotoisomerization of stilbene in the presence of oxygen,726and ‘*‘Sb,I2%b,and 3’Cl n.q.r. spectra are Radio-chlorine exnow available for the 1 : 1 complex SbC13,PhNH2.727 change between labelled SbCI, and hexachloropropene, CC12=CC1CCl,, occurs only at C-1 and C-3 in both dichloromethane solution and in the heterogeneous system at temperatures between 0 and 65 0C.728Labelling does occur at C - 2 , however, at 150°C; exchange is considered to involve carbenium in termed iates . 7’7 718
7’y
720
722
723
724
725
726
727 728
A. J. Edwards and D. R. Slim, J.C.S. Chem. Comm., 1971, 178. M. Mehrain, B. Ducourant, R. Fourcade, and G. Mascherpa, Bull. SOC.chim. France, 1974. 757. N. Habibi, B. Ducourant, R. Fourcade, and G. Mascherpa, Bull. Soc. chim. France, 1973, 21. H. G. Nadler, J. Pebler, and K. Dehnicke, Z. anorg. Chem.. 1974, 404, 230. J. G. Ballard, T. Birchall, J. B. Milne, and W. 1).Moffett, Canad. J . Chem., 1974,52, 2375. V. Piacente and G. Balducci, Rev. Roumaine Chim., 1973. 18, 2083. L. H. Bowen, K. A . Taylor, H. K . Chin, and G. G. Long. J . rnorg. Nuclear Chcm., 1971, 36, 101. P. B. Bertan and S. K. Madan, J. Inorg. Nuclear Chrm., 1974, 36, 983. Yu. P. Egorov, E. V. Ryltsev, and I. F. Tsymhal, Optics and Spectroscopy, 1974, 35, 165. G. N. Salaita, J. Inorg. Nuclear Chem., 1974, 36, 87s. T. B. Brill, J. Magn. Resonance, 1974, 15, 395. F. Boberg and J. Kresse, 2. Naturforsch., 1974, 29b, 213.
Elements of Group V
397
The presence of a square-pyramidal anion has been revealed by an X-ray study of K2SbC15,729 the axial bond being shorter than the mean of the basal bonds, which are distorted as a result of ionic and packing forces. X-Ray p.e. spectra have been reported for M,Sb2X9species, where M = alkali metal and X = C1, Br, or I,',' and this technique demonstrates the presence of both Slow recrystallization of Cs,antimony-(111) and -(v) atoms in CS,S~C~,.'~' Sb,Cl, from dilute hydrochloric acid gives a new @-form in which the caesium and chlorine atoms are in nearly closest packing, with antimony atoms in octahedral The layers are stacked in the order ABACBC, giving rise to two types of SbC1, molecules. Complex tetra-, penta-, and hexa-bromides, together with salts containing the Sb,Br% ion, are the products when SbBr, and amine hydrobromides react in aqueous hydrogen bromide.733 Antimony (v) Compounds. Intercalation of SbF, into graphite occurs very readily, and up to 75% can be incorporated by heating at 110"C for a few D.t.a. studies on solutions of SbF, in water and hydrogen fluoride have defined the thermal treatment required to give crystals of SbF,,2H20, 4SbF,,5Hz0, 3SbF,,2Hz0, and SbFS,HF,2H20.735 Vibrational data for the first and last of these are consistent with the ionic formulations H,O+SbF,OH- and H,O;SbFi, respectively, while donor-acceptor structures are appropriate for the other phases. Both 1: 1 and 1:2 complexes are formed between dimethyl ether and antimony pentafluoride; "F n.m.r. spectra and double-resonance experiments confirm the cis structure (101) for 2SbF,,Me,0.'36 A minor product
from the reaction between SbF, and TeF, has the stoicheiometry TeF4,2SbF, and recently this has been shown to have the formulation 729
730
731
732 '33
734 735
736
R. K. Wismer and R. A. Jacobson, Inorg. Chem., 1974, 13, 1678. M. J. Tricker, Inorg. Chem., 1974, 13, 742. P. Burroughs, A. Hamnett, and A. F. Orchard, J.C.S. Dalton, 1974, 565. K. Kihara and T. Sudo, Actu Cryst., 1974, B30, 1088. N. K. Jha and S. S. A. Rizvi, J . Inorg. Nuclear Chem., 1974, 36, 1479. J. M. Lalancette and J. Lafontaine, J.C.S. Chem. Comm., 1973, 815. B. Bonnet, J. Rozikre, R. Fourcade, and G. Mascherpa, Cunad. J . Chem., 1974, 52, 2077. S. Brownstein and M. J. Farrall, Canad. J . Chem., 1974, 52, 1958.
398
Inorganic Chemistry of the Main - group Elements As is the case in many similar systems, there is considerable cation-anion interaction here through fluorine bridging. Detailed i.r. and Raman data for SbFs,CH,CN are in accord with C,, symmetry for the SbF,N moiety.''' Stabilktion of unusual cations by A s F ~has already been mentioned, and SbFi or SbzF;i are often Convenient alternatives. These have been successfully used in the formation of OlSbF; and 02+sb2~i1,739 C]01Sb2F;1,740 and I:Sb2F1.741 Full structural data are available for the last two compounds. Raman data for SbC1, over a temperature range point to a structure change at -76 "C from the trigonal-bipyramidal monomer to a dimeric form with either D,, or C,,, symmetry.742Two groups of workers report the formation of four hydrates of antimony pentachloride7"'*'"" with from 1 to 4 moles of water. Spectroscopy points to the first being a hydrogen-bonded polymer while the higher hydrates also contain the ionic species [H'(H,0),,][SbC150H]-.743 Enthalpies of complexation with SbCI, for a number of oxygen donors in CCld7",and a series of N-substituted phosph~ramides~'~ have been determined and the 'donor number' has been calculated. A new relationship involving the 'donor number' has been observed from X-ray p.e. spectra of quick-frozen solutions of SbCls.747There is a linear relationship of donor number with the difference in binding energies of the orbitals, implying that on complexation antimony 3&/2 and chlorine 2p1/2,3/2 there is a decrease in the Sb-Cl bond strength and an increase in the d -orbital binding energy. The possibility of a structure involving the acetylium ion appears probable from measurements on the SbC1,-acetic anhydride complex.748 Isomer shifts in the Mossbauer spectra for SbCI5,L, where L = itri rile,'"^ 0PCl3, OPR3, DMF, Cl-,750etc., have been interpreted to show an order of donor power for the ligands. Vibrational assignments and normal-coordinate analyses have been reported for SbCl,,DMSO and SbC15,[2H6]DMS0.7s' Replacement of one chlorine in SbCl, takes place on reaction with sodium ethoxide in dichloromethane, giving the known dimeric ethoxytetrachloride? but definite compounds were not obtained when attempts TembZF~1*737
737
738 739 740 741
742
743 744 745
746
747
748 749
750 751
A. J . Edwards and P. Taylor, J.C.S. Dalton, 1973, 2150. D. M. Byler and D. F. Shriver, Inorg. Chem., 1974, 13, 1412. D. E. McKee and N. Bartlett, Inorg. Chem., 1973, 12, 2738. A. J. Edwards and R. J. C. Sills, J.C.S. Dalton, 1974, 1726. C. G. Davies, R. J. Gillespie, P. R. Ireland, and J. M. Sowa, Canad. J. Chem., 1974, 52, 2048. W. Bues, F. Demiray. and W. Brockner, Spectrochim. Acta, 1974, 30A, 1709. R. Ortwein and A. Schmidt, Z. anorg. Chem., 1974, 408, 42. G. Picotin and P. Vitse, Bull. SOC.chim. France, 1974, 1291. G. Olofsson and I. Olofsson, J. Amer. Chem. SOC.,1973, 95, 731. Y . Ozari and J. Jagur-Grodzinski, J.C.S. Chem. Comm., 1974, 295. K. Burgen and E. Fluck, Inorg. Nuclear Chem. Letters, 1974, 10, 171. K. C . Malhotra and D. S. Katoch, Austral. J. Chem., 1974, 27, 1413. J. M. Friedt, G. K. Shenoy, M. Masson, and M. J. F. Leroy, J.C.S. Dalton, 1974, 1374. J. M. Friedt, G. K. Shenoy, and M. Burgard, J. Chem. Phys., 1973, 59, 4468. M. Burgard and M. J. F. Leroy, J. Mol. Structure, 1974, 20, 153.
Elements of Group V
399
were made to replace further chlorine In the presence of ammonia, however, alcohol reacted complete&, and Sb(OEt),,NH, could be isolated. The monoalkoxy derivatives Sb(OR)Cl, form complexes with a wide variety of amine oxides and phosphine oxides which are monomeric in n i t r ~ b e n z e n e .Monosubstituted ~~~ species also result when antimony pentachloride is treated with either sodium formate or sodium acetate in methylene dichloride,"" and vibrational data for the compounds obtained, SbCl,(O,CH) and SbCI4(0,CMe), have been discussed in terms of monomeric structures. Slightly distorted octahedral SbBr; ions and centrosymmetric Br; ions are present in the structure of (quinolinium),SbBr, according to X-ray diffraction data.755
Bonds to Oxygen.-Mossbauer data have been obtained for (Ph,Sb),O and a series of trialkoxystibines Sb(OR),, where R = E t , Pr, Bun, or Cyclic esters, analogous to those discussed above for arsenic, can be obtained with antimony as the central atom by reactions between PhSbC1, and diols, dithiols, or m0n0thiogly~o1~.~~~ In the refinement of the crystal structure of orthorhombic antimony(rr1) oxide, it was shown that each antimony is co-ordinated to three oxygen atoms (mean Sb-0 2.01 A), with the lone pair completing a pseudo-tetrahedral arrangement.758By sharing corners, these tetrahedra form double infinite chains with the lone pairs pointing outwards. Raman and i.r. data for the oxide halides Sb405C12and Sb405Br2have been obtained and discussed in terms of lattice vibrations.759The analogous iodide is not, however, among the phases identified in an analysis of the Sb,O,-SbI, system, only Sb,O,I, Sb,O,,I, and Sb,071 being detected.760The exact modification of antimony(r1r) oxide obtained by thermal decomposition of Sb,OllCl, depends on the method used for preparing the latter.761With material obtained by decomposing Sb,O,Cl at 460 "C, the product is the less common cubic form of Sb203. The antimony(m) hydroxy-species existing in nitric acid solution was previously thought to be Sb,O,(NO,),H,O, but according to an X-ray Both determination the material is best described as Sb404(OH)2(N0,)2.762 trigonal-bipyramidal SbO, and tetrahedral SbO, units are present R.-A. Laber and A. Schmidt, Z . anorg. Chem., 1974, 405, 71. R. C. Paul, H. Madan, and S. L. Chadha, J. Inorg. Nuclear Chem., 1974, 36, 737. 754 R.-A. Laber and A . Schmidt, Z . anorg. Chem., 1974, 407, 237. 7 5 5 S. L. Lawton, E. R. McAfee, J. E. Benson, and R. A. Jacobson, Inorg. Chem., 1973, 12, 2939. 756 L. H. Bowen, G. G. Long, J. G. Stevens, N. C. Campbell, and T. B. Brill, Inorg. Chem., 1974, 13, 1787. 757 M. Wieber and N. Baumann, 2. anorg. Chem., 1973, 402, 43. C. Svensson, Acta Cryst., 1974, 1130, 458. 759 K. I. Petrov, Yu. M. Golovin, and V. V. Fomichev, Russ. J. Inorg. Chem., 1973,18, 1554. 760 A. M. Klimakov, B. A. Popovkin, and A . V. Novoselova, Doklady Chem., 1973,213,858. 761 R. Matsuzaki, A. Sofue, and Y. Saeki, Chem. Letters, 1973, 1311. 762 J . - 0 . Bovin, Acta Chem. Scand. ( A ) , 1974, 28, 267. 752
753
400
Inorganic Chemistry of the Main-group Elements (in each case the lone pair occupies the final co-ordination position). The former share two edges to build up infinite chains parallel to b, which are linked by the SbO, polyhedra into layers parallel to the bc plane. Two new phases, Sb,MoO, and Sb,(MoO,),, have been identified in the Sb,O,-MoO, and the rare-earth antimonites LnSbO, result when mixtures of the two oxides are sintered at 650°C.764A second report announces similar compounds but the formula is given as 2Ln,03,x Sb203, where x = 3.0-3.8 for Ln =La, Pr, or Nd.765Unit-cell parameters are available for NazSb407and NaSb30,,Hz0,766 and powder neutron-diffraction results have been obtained for the ordered perovskite-like compounds Ba,Sb,LiO,, and the bismuth analogue.767 From solubility measurements on NaSb(OH),, the enthalpy of hydration Addition of has been estimated as -124 kJ mol-' for the [Sb(OH),]acid to a solution of tetraethylammonium antimonite does not immediately lead to the [Sb(OH),]- ion; initially a polymer of high molecular weight is formed, which on long ageing breaks down via various polymeric substances to the monomer.769 Vibrations characteristic of Sb-0 stretches and deformations have been discussed for solid antimonates such as M'SbO,, M"SbzOs, and MYSb207."" Preparation of a new family of mixed oxides with structures related to that of cubic KSbO, has been announced, and the detailed structure of one such compound, Bi,GaSb,O,,, has been Potassium ion transport can occur through two-dimensional tunnels that occur in the structures of K,Sb,O,, and K2Sb4011.772
Bonds to Sulphur, Selenium, or Tellurium.-Electrical and thermal conductivities have been reported for the chalcogenides M'SbS2 and M'SbSe2,773 and X-ray data for aramyoite, Ag(Sb,Bi)S2."" The presence of a Bi,Se,S structure in Sb,Te, and Sb,Te,Se follows from X-ray data, and the relationship with the non-stoicheiometric Sb2Te3-,Se, compounds has been disMass-spectrometric measurements on the vapour in equilibrium with Sb2Te, lead to values of 65.4 and 179.9 kcal mol-' for the heats of atomization for SbTe and Sb2Te2,respectively.776 M. Parmentier, A. Courtois, and Ch. Gleitzer, Bull. Soc. chim. France, 1974, 75. S. N. Nasonova, V. V. Serebrennikov, and G. A. Narnov, Russ. J. Inorg. Chem., 1973, 18, 1095. 765 G.-Y. Adachi, M. Ishihara. and J. Shiokawa, J. Less-Common Metals, 1973, 32, 175. 766 C. Giroux-Maraine, P . Maraine, and R. Bouaziz, Cornpt. rend., 1974, 278, C, 705. 767 A. J. Jacobson, B. M. Collins, and B. E. F. Fender, Acta Cryst., 1974, B30, 1705. 7h8 M. J. Blandamer, J. Burgess, and R. D. Peacock, J.C.S. Dalton, 1974, 1084. 76y J. Lemerle and J. Lefehvre, J. Chim. phys., 1974, 71, 97. "'R. Franck, C. Rocchiccioli-Deltcheff, and J. Guillermet. Spectrochim. Acta, 1974, 30A, 1 ; C . Rocchiccioli-Deltcheff and R. Frank, Ann. Chim. (France), 1974, 9, 43. A. W. Sleight and R. J. Bouchard, Inorg. Chem., 1973, 12, 2314. 772 H. Y.-P. Hong, Acta Cryst., 1974, B30, 945. 773 V. A. Razakutsa, N. I. Gnidash, V. B. Lazarev, E. 1. Rogacheva, A. V. Salov, L. N. Sukhorukova, M. P. Vasil'eva, and S. I. Berul', Russ. J . Inorg. Chem., 1973, 18, 1722. 7 7 4 D. J. E. Mullen and W. Nowacki, Z . Krist., 1974, 139, 54. 7 7 5 T. L. Anderson and B. Krause, Acta Cryst., 1974, B30, 1307. 77h C. L. Sullivan, M. J. Zehe, and K. D. Carlson, High Temp. Sci., 1974, 6 , 80. 76' 764
Elements of Group V
40 1
5 Bismuth
Structures for two bismuthides, BazBi”’“ and CasBi,,777bshow the presence of bismuth in nine-fold co-ordination in the former, while two different co-ordination polyhedra, showing eight- and nine-fold co-ordination, occur in the latter. Powder neutron-diffraction data for BiF, show eight-fold co-ordination for bismuth (Bi-F 2.217-2.502&, but from a comparison with the isostructural YF, it is clear that the lone pair is stereochemically active and occupies a ninth co-ordination New vapour-pressure measurements are now available for BiCl, over the temperature range 151437 0c.779 Competition between Cl-, Br-, and NO; for entry into the co-ordination spheres of Bi3+and Pb2+has been investigated in molten dimethyl sulphone to show the order C1- > Br- >> NO;.780These data are relevant to basicity measurements in molten salts and glasses.781The BiC1,-LiCl system shows the presence of LiCl, BiCl,, and LiC1,4BiC13 A new compound of mixed oxidation state is the product from reduction of a mixture of BiCl, and HfCl, with metallic Full identification was achieved only by an X-ray structure determination, which showed the composition to be Bi+Bi EtOH > Pr'OH > Bu'OH > Me2C0, H 2 0 . The X-ray diffraction data for CsICl, have been refined by Van Bolhuis and Tucker;"* the I-Cl bond is reported to be 2.55 A. In KIBr,,H,O the I-Br bond length in the IBr; ions is 2.71 The CsIC1,-RbIC1,-H,O system at 25 "C has been studied, and solubility data for these two iodine(1) salts have been reported.lo3 Schmeisser et a1.l"" have obtained the i.r. spectrum of solid IF, at -100 "C, and claim that their results confirm the trigonal-bipyramidal structure for IF, molecules. They have proposed that the axial fluorines are involved in fluorine bridging. The Dortmund group have prepared CFJF, by the direct fluorination of CF31at -78 "C in CCl,F;'05 some I9Fn.m.r. data were reported and 1: 1 adducts with MeCN, pyridine, and quinoline were obtained. The okidation of CF31with ClF, at -78 "C in C$14 was shown to yield CFJF.,, although CF31F, was identified as an unstable intermediate under these conditions.106 Solubility data have been obtained for CsICl, in aqueous hydrochloric acid at 25 "C.'"' Cationic iodine(II1) species of the types IX,SO,F and I,XSO,F (X = Br or C1) have been prepared conveniently by the reaction of ISO,F with Cl,, Br2, ICl, or IBr.1"8According to conductivity measurements, all the compounds behave as strong bases in HSO,F, although vibrational spectra in the solid state were assigned in terms of ionic solids, with evidence for strong cation-anion interactions. Burbank and Jones have succeeded in determining the crystal structure of IF, at -80°C by X-ray methods.'"' There are three crystallographically distinct IF, in the molecular lattice; the dimensions of the weighted-average IF, molecule are shown in Figure 1. Each molecule makes a number of 99 loo
*" 101
'04
lo'
'Oh 107 lot(
1 09
H. Harada, D. Nakamura, and M. Kubo, J. Magn. Resonance, 1974, 13, 56. A . A. Ramadan, P. K. Agasyan, and S . I . Petrov, Zhur. analit Khim., 1973, 28, 2396. F. Van Bolhuis and P. A. Tucker, Acta Cryst., 1973, B29, 2613. S. Soled and G. B. Carpenter, Acta Cryst., 1973, B29, 2556. V. I. Safonova, T. A. Ermolenko, V. V. Safonov, K . I. Nikolaeva, and B . D. Stepin, Zhur. neorg. Khim., 1973, 18, 1699. M . Schrneisser, D. Naumann, and E. Lehmann, J. Fluorine Chem., 1973, 3, 441. J. Baumanns, L. Deneken, D. Naumann, and M. Schmeisser, J. Fluorine Chem., 1973,3,323 G. Oates and J. M. Winfield, J.C.S. Dalton, 1974, 119. A. A . Fakeev, Z . V. Ivanova, and B. D. Stepin, Zhur. neorg. Khim., 1973, 18, 2874. W.W. Wilson and F. Aubke, Inorg. Chem., 1974, 13, 326. R. D.Burbank and G. R. Jones, Inorg. Chem., 1974, 13, 1071.
The Halogens and Hydrogen
48 1
Figure 1 Iodine pentafluoride molecule: the dimensions are a weighted average over all three crystallographic types present in the unit cell. (Reproduced by permission from Inorg. Chem., 1974, 13, 1074) contacts with fluorines of other molecules. The primary and secondary contacts are all made below the basal plane, in the same way as has been found to occur with the isoelectronic X e E . Polymeric species were not detected by molecular-beam mass spectrometry in the saturated vapour of IF, at 273K.79 Oates and Winfieldlo6 have prepared trifluoromethyliodine(v) tetrafluoride by the reaction of CF,I with ClF,; they were also able to identify CF,IF, as an intermediate product of this reaction. The same workers attempted to fluorinate other iodine-containing compounds, viz. C,F51,76 FsS(CF2),I ( n = 2 or 4),77and p-C6F412,in the same way:76they were able to identify certain of the reaction products as iodine(v) derivatives with the exception of the material produced from p-C6F41z,where the starting material and the product(s) were too insoluble and it was thought that conversion into g-C6F4(IF4),was i n ~ o m p l e t eThe . ~ ~ CF, and C6F, groups in CF,IF,lo6 and C6FsIF4'" are probably attached in the axial position, although the n.m.r. results are also consistent with fast intramolecular exchange of F on I. The same group of workers have also investigated some substitution reactions of IF,"' and CF31F4'06with methoxomethylsilanes ; they were able to identify a range of methoxoiodine(v) compounds, IF5-, (OMe), and CF,IF,-,(OMe), (n = 1-4). The vibrational spectrum of IF,,SbF, has been assigned tentatively on the basis of the predominantly ionic structure 1% SbF;." The I9Fn.m.r. spectrum of the adduct in liquid HF consisted of only one signal at temperatures between +20 and -80°C, indicating rapid exchange of fluorine between all species present. Finch et al. have determined the standard enthalpies of formation of MIF, (M=K, Rb, or Cs) from their heats of alkaline hydrolysis."' Oxide Halides.-The photolysis of argon matrix samples containing ClF and 0, with 2200-3600 8, radiation has been shown112to produce absorptions 'lo
11'
G. Oates, J. M. Winfield, and 0. R. Chambers, J.C.S. Dalton, 1974, 1380. A. Finch, P. N. Gates, and M. A . Jenkinson, J.C.S. Dalton, 1973, 2237. L. Andrews, F. K. Chi, and A . Arkel, J. Amer. Chem. SOC., 1974, 96, 1997
Inorganic Chemistry of the Main- group Elements attributable to the new species FClO. Secondary reactions produced the known FC10, molecule. No e.p.r. spectra could be detected from photolysed mixtures of pure ClF, and AsF, in previously passivated apparatus;113 however, in the presence of controlled amounts of water, spectra appeared on photolysis which were identical with those obtained by Olah and Comisar~w,~ who ' ~ attributed them to Cl; and ClF'. Morton and Preston's careful experiments have confirmed that the spectra should rather be assigned to ClOCl' and FClO', as was suggested earlier by Symons et ~ 1 . " ~ Accurate molecular constants have now been determined from the microwave spectrum of gaseous FC102.116 The pyramidal molecule, of C, symmetry, has C1-F and C1-0 bond lengths of 1.697 and 1.418& and LFClO and LOClO of 101.7" and 115.2", respectively. The structure was rationalized in terms of a bonding scheme in which a fluorine 2p atomic orbital overlaps with the highest occupied orbital of C10,. N.m.r. relaxation studies by Alexandre and Rigny'" have yielded information on the difference in chemical shifts between the non-equivalent fluorines and the rate of exchange between them. New 1 : l adducts of ClOF, with a number of pentafluorides MF, (M=P, V, Ta, Nb, or Bi) have been obtained and characterized by X-ray powder diffraction measurements.'18 The essentially ionic nature of these compounds was confirmed by means of their vibrational spectra. Solution studies in liquid HF allowed a more confident assignment of some of the cation vibrations. The standard enthalpies of formation of IOF, (-554 kJ mol-') and IO,F (-246 kJ mol-') have been determined from the heats of alkaline hydrolysis at 298 K.l19 The results show that the reaction 2IOF, + I02F+IF, is endothermic by only ca. 2 3 k 6 kJ. Since the number of formal I-F and 1-0 bonds remains constant this implies little change in the bond orders. Moreover, under appropriate conditions the reaction may be reversed; during the synthesis of I02F, from IOF,, the driving force is clearly the continual removal of IF,. Edwards and Taylor's1'' observations are consistent with the existence of such an equilibrium: these workers have redetermined the crystal structure of TOF, and have argued for a new assignment of the oxygen atom to the equatorial position: the reported 1-0, I-Fequat., I-Faxla, bond lengths are 1.71, 1.84, and 1.90 A in the trigonal-bipyramidal IOF, molecules of this essentially molecular structure. The existence of two isomeric forms of IO,F, has now been disproved. Molecdar121and masslZ2spectrometry as well as apparent molecular weight 482
113
'I5 ' I h
118
'"' 12'
J. R. Morton and K. F. Preston, Inorg. Chem., 1974, 13, 1786.
G. A. Olah and M. B. Comisarow, J . Amer. Chem. Soc., 1968, 90, 5033; 1969, 91, 2172. R. S. Eachus, T. P. Sleight, and M. C. R. Symons, Nature, 1969, 222, 769. C. R. Parent and M. C. L. Gerry, J. Mol. Spectroscopy, 1974, 49, 343. M. Alexandre and P. Rigny, Canad. J. Chem., 1974, 52, 3676. E. Bougon, T. Bui Huy, A. Cadet, P. Charpin, and R. Rousson, Inorg. Chem., 1974,13,690. A. Finch, P. N. Gates, and M. A. Jenkinson, J.C.S. Dalton, 1973, 2725. A. J. Edwards and P. Taylor, J. Fluorine Chem., 1974, 4, 173. 1. R. Beattie and G. J. Van Schalkwyk, Inorg. Nuclear Chem. Letters, 1974, 10, 343. A. Engelbrecht, 0. Mayr, G. Ziller, and E. Schandara, Monatsh., 1974, 105, 796.
483 measurements121have clearly shown that the monomer (C2usymmetry) is in equilibrium with oligomeric species. It has been pointed out that this oxide fluoride, isoelectronic with SbF5, melts sharply and is only modestly viscous and, therefore, is not extensively polymerized. The Raman spectrum of IO,F, and 19Fn.m.r. studies of the 1:1 adduct with SbF, are indicative of the formation of cis oxygen bridges between the molecules. The Halogens and Hydrogen
Oxides and 0xyanions.-The photochemical d e c o m p ~ s i t i o n 'of~ ~F,O at temperatures S272 "C is analogous to the thermal decomposition, i.e. the first step is F,O + F+FO. Clyne and Watson124have described their sampling system for free radicals, produced in a discharge-flow apparatus and detected by mass spectrometry. By these means they measured the rate constants of reactions involving F atoms and FO radicals. The Raman spectrum of F,O, has been d e t e ~ m i n e d in ' ~ ~solution, in CF,Cl, for the first time: it is of interest to note that no bands assignable to v ( 0 - 0 ) could be detected. The impulse photolysis of gaseous 0,-F, mixtures, under conditions known to cause no dissociation of O,, has been shown to generate FO, radicals.lZ6 It has been suggested"' that oxides of chlorine, ClO,, constitute an important sink for stratospheric ozone. The proposed photochemical scheme predicts that C10 is the dominant chlorine-containing constituent of the lower and middle stratosphere. The efficiency of 0,-destruction of the C10, catalytic cycle appears to be greater than that of the NO, cycle. Laser photolysis (4880A) of C1,O in an Ar matrix has been shown to yield the Cl-ClO photoisomerism product, as well as C10.'"" A dimeric form of the latter, Cl-0-Cl-0, was identified in the products of the of the mercury arc photolysis of Cl,O-O, matrix samples. The as~ignrnent"~ e.p.r. spectra from photolysed ClF,-AsF, samples, containing traces of water, in terms of a mixture of ClOCl' and FClO' has been mentioned already. The chlorite anion, CIO;, can be generated in an Ar matrix at 15 K by the codeposition of C10, and an alkali Three intense i.r. absorptions were attributed to vibrations of the anion. The C1-0 force constant (4.1 1mdyn k') is less than that of C10, (6.61 mdyn A-'), which is consistent with the antibonding character of the additional electron. A kinetic study has been p~blished'~'of the reaction of OC1- and ClO; in aqueous solution. Two principal reactions, both third-order, were established. Hydrolysis of OC1- generates HClO, which reacts with ClO;, liberating ClO,. In *" E. Ghibaudi, J. E. Sicre, and H. J. Schumacher, Z. phys. Chem. (Frankfurt), 1974, 90, 95. lZ4
M. A . A. Clyne and R. T. Watson, J.C.S. Faraday I, 1974, 70, 1109.
"' J. K. Burdett, D. J. Gardiner, J. J. Turner, R. D. Spratley, and P. Tchir, J.C.S. Dalton, 1973, 1928. I"' P. P. Chegodaev, V. I. Tupikov, and E. G . Strukov, Zhur. jiz. Khirn., 1973, 47, 1315. l z 7 R. S. Stolarski and R. J. Cicerone, Canad. J. Chem., 1974, 52, 1610. F. K. Chi and L. Andrews, J . Phys. Chem., 1973, 77, 3062. "" D. E. Tevault, F. K. Chi, and L. Andrews, J. Mol. Spectroscopy, 1974, 51, 450. 130 H. Imagawa, M. Fukagawa, and Y. Tanaka, Nippon Kagaku Kaishi, 1974, 238.
Inorganic Chemistry of the Main- group Elements the second step, C10, reacts with OC1- to form CIO;. The electrolytic oxidation of C10; in anhydrous neutral DMSO two waves, of which the primary one is characteristic of the rapid reversible reaction:
484
C10; + C102+ eThe reduction of C10, in DMSO is complex: it can be summarized by the equation: 8C10, + 4e- + 4C1- + 2C1,07+ 0, The e.s.r. spectrum of C10, trapped in noble-gas matrices has been investigated at 4.2 K."" Laser excitation studies using four argon ion lines on C102, in noble-gas or N, matrices at 1 6 K , have been described:133 resonance effects were obtained with 4579 ,& excitation. The kinetics of the hydrolysis of C10, have been i n ~ e s t i g a t e d 'in ~ ~aqueous solution over the ranges of temperature (40-80°C) and p H (2-7) corresponding to those used in pulp bleaching operations. Yeats and A ~ b k e ' ,have ~ identified the products of reaction of ClO,SO,F and excess AsF, or SbF, as C10,[S03F,AsF,] or C102[Sb,F,,]. Crystals of the latter compound were also produced from the interaction of Cl,, ClF,, and SbF, in Pyrex apparatus.136Single-crystal X-ray diffraction studies by Edwards and Sills showed that, although the molecular geometry is consistent with the ionic formulation, there is considerable interaction between the ions through fluorine bridging. An i.r. and Raman study of MC10, (M =Li, Na, or K) in matrices of Ar or Xe has given data on the monomer ion pairs; dimers were also obThe quadrupole interaction for the paramagnetic centres in irradiated MClO, (M = K or Na) has been measured by e.s.r. s p e c t r o ~ c o p y . ~ ~ ~ The coupling was found to be consistent with the field gradient obtained from a calculation for c103. The formation of c103on the irradiation of perchlorates is now well established: the e.s.r. spectrum of this radical shows a characteristic temperature dependence. Additional experimental evidence as well as CNDO calculations are said to be consistent with the existence of two modifications of the radical, related to each other by an inversion, together with a lattice ~ i b r a t i 0 n . l ~ ~ According to Jander and co-worker~'"~ the reactions of C1,0, with NH, or RNH, ( R = M e , Bun, But, or cyclohexyl) produce NH:[NHClO,]and RNHClO,, respectively. The acidic hydrogens on N could be replaced with 13' 132
13'
134 195
13' 14('
J. Bessara and G. Cauquis, Bull. Soc. chim.France, 1973, 1936. C. A. McDowell, P. Raghunathan, and J. C. Tait, J. Chem. Phys., 1973, 59, 5 8 5 8 . F. K. Chi and L. A n d r e w , J. Mot. Spectroscopy, 1974, 52, 82. G. Von Heijne and A. Teder, Acta Chem. Scand., 1973, 27, 4018. P. A. Yeats and F. Aubke, J. Fluorine Chem., 1974, 4, 243. A. J. Edwards and R. J. C. Sills, J.C.S. Dalton, 1974, 1726. N. Smyrl and J. P. Devlin, J. Chem. Phys., 1974, 60, 2540. J. R. Byberg, Chem. Phys. Letters, 1973, 23, 414. K. Shimokoshi and Y. Mori, J. Phys. Chem., 1973, 77,3058. D. Baunigarten, E. Hiltl, J. Jander, and J. N. Maussdoerffer, Z. anorg. Chem., 1974, 405, 77.
The Halogens and Hydrogen 485 metal cations to form salts. An addition to the range of halogenoalkyl perchlorates is CF,OClO,; it has been prepared141by the action of C1Oc10, Its on CFJ, and characterized by i.r.,I4' 19Fn.m.r., and mass stability in stainless steel apparatus is good: it decomposes thermally in the presence of CsF to give COF, and FClO,. Schack and Christe have also examined the reactions of pure 0, with a series of covalent hyp0ha1ites.l"~ Oxidative oxygenations of the terminal halogen occurred with C10C10, and ClOSO,F, as well as with BrONO, and BrOClO,: the products obtained were, respectively, O,ClOClO,, O,ClOSO,F, O,BrONO,, and the new compound O,BrOClO,. Under similar conditions ClONO, or C10, were converted into N02'C104and Cl,06. 1.r. and mass spectroscopy were used to show that, above its melting point, Cl,06 has the oxygen-bridged chloryl perchlorate structure. The role of C10; as a ligand in solution has been reviewed by Johans~ 0 n . l ~Perchlorate-ion-selective " electrodes prepared using liquid ionexchangers in PVC are said14' to exhibit approximately the same characteristics as the commercially available electrode: the selectivity of the new electrode was claimed to be superior. The ion-exchanger was mixed with PVC dissolved in THF and the mixture dried as a membrane disc or used to coat a Pt electrode: the useful life ranged from 2 weeks, for a wire electrode, up to a month. The decomposition of Cloy ions in a eutectic mixture of NaN0, and KNO, (420-460 "C) is a u t ~ c a t a l y t i csince , ~ ~ ~C1- ions are formed and these catalyse further decomposition. The same group of workers have also investigated the reaction between C10; and C1- ions in a mixture of fused nitrates in the presence of BaZ+and CO,.'"' The rate of decomposition of have shown C10, depends on the flow rate of CO,. Kung and that it is possible to vapourize polycrystalline ammonium perchlorate in the form of a compressed pellet in vacuo by means of surface heating; only dissociation, as opposed to decomposition, products were detected, i.e. only NH, and HC104 were found in the vapour phase. The kinetics of the disappearance of the BrO transient, formed during the pulse radiolysis of 0, + Br or N,O + Br, mixtures, have been in~estigated.'~' Second-order kinetics were confirmed although additional effects, due to gas pressure and dosage, were detected. Bromine(m) oxide, Br203, has been prepared by the thermal decomposition of Br204.15'The vibrational specbond, but it has not been trum of Br,O, shows the presence of a Br-0-Br 14'
14' 14'
1 4 ' '45
146 14'
149
C. J . Schack, D. Pilipovich, and K. 0. Christe, Inorg. Nuclear Chem. Letters, 1974, 10, 449. C. J. Schack and K. 0. Christe, Inorg. Chem., 1974, 13, 2374. C. J. Schack and K. 0. Christe, Inorg. Chem., 1974, 13, 2378. L. Johansson, Coordination Chem. Rev., 1974, 12, 241. T. J. Rohm and G. G. Guilbault, Analyt. Chem., 1974, 46, 590. I. Horsak and I. Slama, COIL Czech. Chem. Comm., 1973, 38, 2366. I. Horsak, I. Slama, and Z. Kodejs, Coll. Czech. Chem. Comm., 1973, 38, 2833. R. T. V. Kung and R. Roberts, J . Phys. Chem., 1974, 78, 1433. R. W. Cahill and J. F. Riley, Radiation Res., 1974, 58, 25. J. L. Pascal, A. C. Pavia, J. Potier, and A. Potier, Compt. rend., 1974, 279, C, 43.
Inorganic Chemistry of the Main- group Elements
486
possible to distinguish between the two forms OBrOBrO and BrOBrO,. E.s.r. spectra of Br0:- defects’” in KBr0, crystals, at temperatures below 115 K, correspond to three distinct BrOg- orientations in the l a t t i ~ e : ~ ” above this temperature the spectra merge. These radicals were previously thought to be BrO,; it is likely that the uncharged radicals are present in X-irradiated bromate-doped KNO, cry~ta1s.l~’ The kinetics of the oxidation of Br- by BrO;, in the eutectic melt NaN0,-KNO,, have been studied in the presence of Ba2+and C0,.’s3 The reaction order with respect to COz, Ba2+, and Br- is 0.6, 0.6, and 1.0, respectively. Pergola”“ has shown that the voltammetric reduction of perbromate at Pt is described by the equation: BrO;
+ 2H’+
BrO;
2e-
+ H,O
However, in O.1M-HC10, the reduction curve at platinized Pt is compatible with an 8e- reduction to Br-. The crystal structure of (IO),SO, has been determined at 100 K.’” It possesses a layer structure, with the layers comprising infinite (10), spiral chains linked by SO, tetrahedra. The reduction of 10; by N2H4to produce I- has been studied by means of an electrode sensitive to I- i011s.l’~The rate of reduction at low [I-], < 5 x lo-’ mol 1-’, is controlled only by the direct reaction with N2H4. At higher [I-], reduction by I- occurs, to form I,, which is in turn reduced to I- by hydrazine. ‘’’I N.q.r. spectroscopy of MH2(103)3 (M=Rb, NH4, or K), Ba(IO,),,H,O, and LiCr(I0,) at 77 K has established the presence of covalently bonded 10, groups in the tri-iodate~.~” The kinetics of the reaction between I- and 10; in a LiC1-KCI melt have been studied.”* The reaction yields the sparingly soluble LiJO, according to the equation: 210;
+ 31- +. 10:- + 21,
III the presence of 02,1- is oxidized in such melts to I, and Li,10,.1’9 However, 102- reacts with I- in the presence of CO, to form I, and COZ-. A similar reaction was found to occur in a eutectic melt of NaNO, and KNO, at 340°C.’60 The reaction proceeds according to: 10; 15’ 152 153
154 Is’
15’
159 Iho
+ 51- + 3C0,
-+
31, + 3CO:-
J. R. Byberg and 13. S. Kirkegaard, J. Chem. Phys., 1974, 60, 2594. J. R. Byberg, S. J Jensen, and B. S . Kirkegaard, J. Chem. Phys., 1974, 61, 138. Z . Kodejs, I. Horsak, and I. Slama, Coll. Czech. Chem. Comm., 1973, 38, 2839. F. Pergola, J. Elecironalyt. Chem. Interfacial Electrochem., 1974, 51, 461. S. Furuseth, K. Selte, H. Hope, A. Kjekshus, and B. Klewe, Acta Chem. Scand., 1974, 28, 71. K. A. Hasty, Mikrochim. Acta, 1973, 925. T. G. Balicheva, V. S. Grechiskin, G. A. Petrova, and V. A. Shishkin, Zhur. neorg. Khirn., 1973, 18, 3200. P. Pacak, I. Slama, and I. Horsak, Coll. Czech. Chem. Comm., 1973, 38, 2347. P. Pacak and I. Slama, Coll. Czech. Chem. Comm., 1973, 38, 2355. P. Pacak and I. Slama, Coll. Czech. Chem. Comm., 1973, 38, 3595.
The Halogens and Hydrogen
487
the rate being first-order with respect to [I-] and also to the partial pressure of co,. The complete set of fundamental frequencies of tetragonal NaI04 has been determined.161The spectrum of the trigonal trihydrate was found to be inconsistent with Burger's structure, and a more plausible structure was proposed. The vibrational spectra of Ba,MIO6 (M = Li, Na, K, or Ag) and SrzNaI06have been interpreted;16' differences between the different sets of force constants have been explained in terms of the cations involved. In basic aqueous solution 10, oxidizes ruthenate(v1) to perruthenate, with which it then forms a c0mp1ex.l~~ Hydrogen Halides.--We~tleyl~~has summarized the rate data for reactions of (i) halogen atoms with hydrogen-containing compounds and (ii) hydrogen atoms with halogen-containing compounds, to form vibrationally excited HX, and also reactions for the vibroexcitation of HX molecules. Numerous studies have been published of energy transference involving the hydrogen halides; for example, the investigations, both experimental and theoretical, of the temperature dependence of energy-transfer rates may be mentioned here.'65 However, the chemiluminescence bands observed in the reaction of C2H6,or NH,, are due to the atomic fluorine with CH,, but not with HZ, formation of CH, radicals and not to vibrational relaxation of HF molecules.'66 The saturated vapour pressure of H F has been redetermined for the temperature range 273-303 K:167this leads to a calculated boiling point of 292.90K7 at which temperature the association factor is estimated to be 3.75. Raman scattering by monomeric H F in the gaseous state and at low concentration in liquid SF, has been studied by Le Duff and Holzer;16*" Birnbaum has confirmed that rotational fine structure is evident in the The Raman work also yielded some far4.r. spectrum in solution in SF6.'68b results on the HF polymer bands at 2900-3800cm-l; these were said to be consistent with the presence of hexameric and tetrameric species.16'" The mean amplitudes of vibration of the cyclic hexamer (HF), have. been and the results compared with those from electron diffraction. Measurements of the heats of solution and of neutralization of HF as well 161
163
164
165 166
16' 16'
169
H. Poulet and J. P. Mathieu, J. Raman Spectroscopy, 1974, 2, 81. J. T. W. D e Hair, A. F. Corsmit, and G. Blasse, J. Inorg. Nuclear Chem., 1974, 36, 313. G. I. Rozovskii, Z. Poskute, A. Prokopcikas, and P. Norkus, Zhur. neorg. Khim., 1973, 18, 2696. F. Westley, Nut. Bur. Standards (U.S.A.) Special Publ., 1974, 392. ( a ) J. F. Bott, J. Chew. Phys., 1974,60,427; ( b ) R. A. Lucht and T. A. Cool, ibid., p. 1026. G. K. Vasil'ev, V. B. Ivanov, E. F. Markarov, A. G. Ryabenko, and V. L. Tal'roze, Doklady Akad. Nauk S.S.S.R., 1974, 215, 120. I. Sheft, A. J. Perkins, and H. H. Hyman, J. Inorg. Nuclear Chern., 1973, 35, 3677. (a) Y. L e Duff and W. Holzer, J. Chem. Phys., 1974, 60, 2175; ( b ) G. Birnbaum, Mol. Phys., 1973, 25, 241. S. J. Cyvin, V. Devarajan, J. Brunvoll, and 0. Ra, Z. Naturforsch., 1973, 28a, 1787.
Inorganic Chemistry of the Main- group Elements as some enthalpies of dilution have been carried out in a reaction calorimeter.17’ These results have been combined with some earlier data to obtain the enthalpy of solution of HF as a function of composition, between HF,mH,O and HF,H20. Vasil’ev and Kozlo~skii~” have also determined some heats of dilution of aqueous HF calorimetrically as well as heats of neutralization, H* -tF- + HF, and reaction, H’ + 2F- + HF;. There are also some new values of the equilibrium constants for these two reaction^.'^' Russian workers have also investigated the same equilibria, with aqueous dioxan as s01vent.l~~ Vaillant et al. have redetermined the acidity function for the HF-H,O system for a range of c o m p ~ s i t i o n .Russian ’~~ workers have reported solubility data for MF, ( M = E u , Tb, Dy, or H o ) ” ~ and some hexafluoro~tannates~~~ in aqueous HF. Voitovich et al.’” have investigated the HgIHg2F2,HFelectrode system in detail. They find that it is characterized by a high degree of reversibility and that the stability and reproducibility of its potential are appreciably greater than those of a hydrogen electrode. A three-electrode PTFE cell has been constructed and has been shown to be suitable for the application of controlled-potential techniques to the study of electrode reactions in anhydrous HF.’78Fleischmann et al. went on to investigate the evolution of fluorine at a Pt electrode at 273 K: they concluded that the electrochemical reaction mechanism involves PtF‘,, PtF,, F-, and HF, and that the ratedetermining step is 2PtF, -+ 2PtF, + F,. The same workers have also compared the behaviour of nickel and vitreous carbon with Pt in liquid HF and reported on the oxidation of several organic compounds at these anodes. A French group has examined the electrochemical behaviour of perylene and Br, in an HF medium.179Martin and Clement’*’ have designed and tested an apparatus and a series of reference electrodes for electrochemical studies in anhydrous HF. The use of a vitreous carbon electrode for voltammetry in aqueous HF allows potentials to be observed which are almost as negative as those obtained with rnercury.l8’ There is also an extension in the positive sense. A patent from Uranit GmbH implies that the perfluoroalkylamines
488
G. K. Johnson, P. N. Smith, and W. N. Hubbard, J. Chem. Thermodynamics, 1973,5, 793. V. P. Vasil’ev and E. V. Kozlovskii, Zhur. neorg. Khim., ( a ) 1974, 19, 267; ( b ) 1973, 18, 2902. M. Salomon and B. K . Stevenson, .J. Chem. and Eng. Data, 1974, 19, 42. 173 N. V. Bausova and L. I. Manakova, Zhur. neorg. Khim., 1974. 19, 1213. 174 A. Vaillant, J. Devynck, and B. Tremillon, Analyt. Letters, 1973, 6, 1095. Sh. A. Abdukarimova, N. S. Nikoiaev, and Sh. Dzhuraev, Izvest. Akad. Nauk Tadzh. S.S.R., Otdel. Fiz. Mat. Geol.-Khim. Nauk, 1973, 57. 17‘ I. I. Tychinskaya, N. F. Yudanov, Z. A. Grankina, and K. S. Ivcher, Zhur. neorg. Khim., 1973,18, 3119. 177 Ya. N. Voitovich, V. Ya. Kazakov, and T. F. Starkova, Electrokhimiya, 1974, 10, 404. 17’ A. G. Doughty, M. Fleischmann, and D. Pletcher, J . Electroanalyt. Chem. Interfacial Electrochem., 1974, 51, 329, 456. 17’ A. Thiebault and M. Herlem, Compt. rend., 1974, 278, C, 443. D. Martin and J. Clement, Rev. Chim. mintrale, 1973, 10, 621. A. M. Bond, T. A. O’Donnell, and R. J. Taylor, Analyt. Chem., 1974, 46, 1063. 17’
171
The Halogens and Hydrogen
489
C,F,NH,,(R,),N (R, = C,F, or C4F9), as well as some related perfluoroethylenediamines and cyclic amines, are sufficiently basic and chemically inert to enable HF to be separated from its mixtures with UF6.18' Asprey and PainelS3have shown how pure P-UF, may be prepared from UF, by reduction with Si powder in anhydrous HF: they also indicated the extent of general applicability of the method. Koehnlein et al.lS4have found that the healing times of HF burns on rats (i) after injection with calcium gluconate, (ii) after injection with calcium gluconate and hyaluronidase, and (iii) with no treatment at all, were 34, 27, and 17 days, respectively. Furthermore, they observed that excision of damaged tissue resulted in primary wound healing after 7 days. The dominant chemical form of chlorine in the atmosphere is HCl;18' it is produced mainly from aerosols of marine origin. The role of C1 compounds as catalysts for the recombination of oxygen was discussed and shown to play no major role in the normal atmosphere. The molecular motions of liquid and of paraelectric solid HCl have been studied by analysis of Raman lineshapes.186 Hydrogen iodide prepared by the hydrolytic decomposition of PI, has been analysed by mass spectrometry and gas chr~matography;'~~ it was found to contain hydrocarbon, halogenocarbon, and other impurities. According to Lerner and Cagliostro,188HBr and HI are approximately equally effective as flame inhibitors for the air-C,H, system. 2 Hydrogen
Protonic Acid Media.-More information on this topic will be found under those headings dealing with the individual protonic acids. Russell and Senior189have established that trifluoromethanesulphonic acid behaves as a weak acid in 100% sulphuric acid. Measurements of mol kg-' at 25 "C, which conductivities were used to determine K,, 8 x is comparable with the value for chlorosulphuric acid but smaller than that for fluorosulphuric acid. Electrochemical studies of CF,S03H have shown that it is possible to obtain very high potentials, comparable with or higher Thus this than those in other acids, such as H,SO,, HS03F, and medium is particularly well suited to the study of strongly oxidizing reagents. M. Pfistermeister and J. Pokar, Ger. Offen., 2 231 893, 1974 (Chem. Abs., 1974, 80, 122 901). L. B. Asprey and R. T. Paine, J.C.S. Chem. Comm., 1973, 920. lS4 H. E. Koehnlein, P. Merkle, and H. W. Springorum, Surg. Forum, 1973, 24, 50. l S 5 S. C. Wofsy and M. B. McElroy, Canad. J . Chem., 1974, 52, 1582. lS6 C. H. Wang and R. B. Wright, Mol. Phys., 1974, 27, 345. "' V. Ya. Dudorov, N. Kh. Agliulov, and V. I. Faerman, Zhur. analit. Khim., 1974, 29, 361. N. R. Lerner and D. E. Cagliostro, Combustion and Flame, 1974, 21, 315. 189 D. G. Russell and J. B. Senior, Canad. J. Chem., 1974, $2, 2975. 190 J. Verastegui, G. Durand, and B. Tremillon, J. Electroanalyt. Chem. Interfacial Electrochem., 1974, 54, 269.
490
Inorganic Chemistry of the Main- group Elements
The n-type Silstainless steel combination electrode has been examined more critically as a general acid monitor and also as a selective H F analyser by McKaveney and Buck.19*Dissociation constants have been measured by the 'ladder' technique for a series of buffer acids in 80% aqueous DMSO."' The series of acid-base indicators used provides a convenient method for determining p H values reasonably accurately in this solvent. Bonnet et al.'"' have studied solutions of SbF, in H 2 0 and HF by d.t.a.: in this way they were able to determine the conditions needed to obtain the stable crystalline phases SbF,,nH,O (n = 2 , 5/4,1, or 2/3) and SbF,,HF,H,O. Two of the products (SbF,,2H20 and SbFs,2H20,HF)were shown to be best described by the formulations H30+SbF,(OH)- and H,O: SbF;. 1.r. spectroscopic studies on H X , n H 2 0 (X = C1 or Br; n = 1-4) by Gilbert and Sheppard'"" have confirmed the presence of H 2 0 , H,O+, and H,O: units, consistent with the known crystal structures. This work appears to provide the first report of a crystalline phase corresponding in composition to HC1,4H20.
Hydrogen-bonding.-Pedersen has analysed the hydrogen-bonding geometries of the 190 crystals, studied by neutron diffraction, in which H 2 0acts as a donor.195He concludes that the equilibrium configuration of the bond is linear and that the bending of the bond is isotropic. A theory of the intramolecular contributions to the broadening of v(XH) absorptions of hydrogen-bonded species has been proposed by Coulson and R 0 b e r t ~ o n . The l ~ ~ theory is able to describe both vibrational predissociation and the formation of sum and difference bands. For a given proton donor the chemical shift of the proton has been shown to correlate with the enthalpy change for minor structural changes in the proton a ~ c e p t 0 r . This l~~ work was carried out using CHCl, as the proton donor and with ethers and amines as bases. Further n.m.r. and i.r. spectroscopic studies have been reporteds4 of the interactions between carboxylic acids, e.g. acetic and trifluoroacetic acids, and bases, such as F- and carboxylate anions. NH:(D),-, +D, with D = Gas-phase equilibria of the type NH,'(D), NH3, H20, or mixtures of NH, and H 2 0 have been measured by highpressure mass ~pectrometry.'~~ It was deduced that NH, forms stronger hydrogen bonds to NH:, for low values of x, than does H,O. Gas-phase studies of proton solvation by donors, L, have been extended by Kebarle and G r i m ~ r u d lto~ ~include methanol and diethyl ether. The temperature dependence of the (n, n - 1) equilibria for H'(L), G H+(L)n-l+ L was obtained so that AGO, AH", and AS" could be evaluated for each stage. The J. P. McKaveney and M. D. Buck, Analyt. Chem., 1974, 46, 650. E. H. Baughman and M. M. Kreevoy, J. Phys. Chem., 1974, 78, 421. "' B. Bonnet, J. Roziere, R. Fourcade, and G. Mascherpa, Canad. J. Chem., 1974, 52, 2077. 1 9 4 A . S. Gilbert and N. Sheppard, J.C.S. Faraday 11, 1973, 69, 1628 ' 9 5 B. Pedersen. Acta Cryst., 1974. B30, 289. 1 9 6 C. A . Coulson and G. N. Robertson, Proc. Roy. SOC., 1974, A337, 167. '91 K. F. Wong, T. S. Pang, and Soon Ng, J.C.S. Chem. Comrn., 1974, 5 5 . '91 J. D. Payzant, A. J. Cunningham, and P. Kebarle, Canad. J. Chem., 1973, 51, 3242. 1 9 9 E. P. Grimsrud and P. Kebarle, J . Amer. Chem. SOC., 1973, 95, 7939. 19'
IY2
491
The Halogens and Hydrogen 12
c " " '
01 1
I
1
1
1
1
2
3
4
5
6
7
n
Figure 2 AAGO plot of water (-) and methanol (---). The higher stability of the n = 3 relative to the n = 4 cluster in methanol is seen by the 'bump' at n = 3 in the methanol curve. A larger maximum indicates higher stability of the n = 4 relative to the n = 5 cluster in water. (Reproduced by permission from 3. Amer. Chem. SOC., 1973, 95, 7939) results show a dramatic drop in AGO for E t 2 0 between n = 2 and 3, which must be attributed to the blocking of hydrogen bonding. Small discontinuities in values for H,O and MeOH indicate somewhat more stable structures for H+(MeOH), and H+(H20)4(see Figure 2). In a subsequent study2" the following differences in the proton affinities/kcal mol-' were evaluated : H,O_'eMeOHLEt,O Borah and Wood2" have investigated the hydrogen-bonded complex cation Et,NHpy+, and its deuteriated analogue, by i.r. spectroscopy. The *O0 201
K. Hiraoka, E. P. Grimsrud, and P. Kebarle, J. Amer. Chern. SOC.,1974, 96, 3359. B. Borah and J. L. Wood, J. Mol. Structure, 1974, 22, 237.
492
Inorganic Chemistry of the Main- group Elements
hydrogen bond was found to be unsymmetrical and the complex was considered to be weaker than the Me3NHpy' analogue. The proton-donor abilities of HCl and HF have been compared theoretically by carrying out ab initio MO studies of complexes with proton acceptors.'" The structures and hydrogen-bond energies of (HCl), and HCl-HF complexes were also predicted. The interaction potential between two rigid HF molecules has been calculated in connection with a study of energy transfer in the HF-HF ~ y s t c m . ~The " ~ equilibrium geometry of planar (HF), was also predicted. Ab initio quantum-mechanical electronic structure calculations predict that the linear symmetric FHF molecule is unstable.2MThe barrier height for F + HF -+ FH + F exchange was predicted to be 218 kcal mo1-l. Del Bene'" has reported the results of calculations on adducts in which H,O and HF behave as H' donors towards molecules containing T-electrons. The crystal structure of the ferroelectric phase of NH,[H(CICH,COO),] has been determined at 80 K.'06 The hydrogen bis(ch1oroacetatc) anion retains almost the same conformation as that in the paraelectric phase (above 128 K), including a very short hydrogen bond of length 2.46 A; however, the N atom of the cation has shifted away from the two-fold axis of the paraelectric phase. The hydrogen-bond lengths within the (HCO,):units in KHCO, have been obtained from the crystal structure determinations at 298, 219, and 95 K:'07 the deuterium-bond lengths are all approximately 0.02 A longer. Crystals of NaC1,2C,H,,0,,5Hz0, where C,H,,O, is 1,4,7,1O-tetraoxacyclododecane,contain C1- ions apparently hydrogenbonded to four water The water molecules themselves form rings, consisting of 6 water molecules joined by hydrogen-bonds which are linked by a spiro oxygen that is hydrogen-bonded to 4 other oxygens. Harmon et al."" have pointed out that the H F solvates of MF salts fall into one of two classes. For MF(HF),, where M is a simple cation, the stability sequence is n = 1 > n = 2 > n = 3; however, for hydrogen-bonding cations, e.g. H 3 0 + and NK', stability is n = l > n = 3 , with n = 2 not observed as solid phases. Accordingly, Harmon et al. have reinvestigated PhNH3F,3HF and have shown that the compound reported in 1928 to have this composition was almost certainly the hexafluorosilicate salt, (PhNH3)&F6. Studies of the a.c. behaviour and interfacial phenomena of solid KHF2 have led to the conclusion that the a-phase is a H' conductor, whereas the P-phase is not.210 P. Kollman. A. Johansson. and R. Rothenberg. Chem. Phys. I x t t P r , y , 1974, 24, 199. D. R. Yarkony, S. V. O'Neil, H. F. Schaefer, C. P. Baskin, a n d (3. F. Render, J. Chem. Phys.. 1974, 60, 855. '04 S. V. O'Neil, H. F. Schaefer, a n d C. F. Bender, Proc. Nat. Acad. Sci. U.S.A., 1974, 71, 104. ' 0 5 J. E. Del Bene, Chem. Phys. Letters, 1973, 23, 287; 1974, 24, 203. '06 M. Ichikawa, Acta Cryst., 1974, B30, 651. '07 J. 0. Thomas, R. Tellgren, a n d I. Olovsson, Acta Cryst., 1974, B30, 3155. 'Ox F. P. van Remoortere a n d F. P. Boer, Inorg. Chem., 1974, 13, 2071. 209 K. M. Harmon, S. L. Madeira, a n d R. W. Carling, Inorg. Chem., 1974, 13, 1260. z i n J. Bruinink, J. Electroanalyt. Chem. Interfacial Electrochem., 1974, 51, 141. '02
'.'
P
(4,3) 10.3k0.7 11.1 14.2d
(2J) (33 24.4k0.4 23;4*0.8 20.8 23.2 21.2" 24.gd
Arshadi et d.(ref. 214);
(190) 23.5*0.4 16.5 20.8'
A
( 2 , ~ (32) 15.2+0.2 11.7k0.3 12.7 11.7 17.9' 15.1d
ASa f
A
\
AH0
A11 energy values/kcal mol-', entropy/e.u., standard state 1 atm;
(LO) CI-(HCI), 23.7k0.2 CI-(H20),b 13.1 OH-(H,O), 24.0'
System
f \
(LO) 16.7*0.3 8.2 17.8'
Payzant et al. (ref. 215);
f
> (4,3) 2.4*1.0 3.4 5.4d
Arshadi and Kebarle (ref. 216).
7.9k0.2 6.5 11.5"
A
(3,2) 4.7k0.3 4.5 7.7d
(n,n- 1). Data for AG98
= Cl-(HCl)n-l+HCI;
(4,3) 26.7k2.0 25.8 29Sd
Table 1 Thermodynamic data" [from measurement of gas-phase equilibria CI-(HCI), Cl-(H,O), and OH-(H,O), are given for comparison]
Inorganic Chemistry of the Main- group Elements 494 Jiang and Anderson have used the same semi-empirical method for investigating the hydrogen-bonding in HCl;, HBri, HI;, and HBrCl- as they used for HF, and H50:.211The equilibrium constants Kcn,n for the gasphase reactions Cl-(HCl), = Cl-(HCl)n-l +HCl have been measured at different temperatures with a high-pressure mass spectrometer."* The equilibrium constant K , for Cl-D - - - OMe, over the temperature range 22132 "C has been obtained from the integrated intensity of the Raman band of unassociated DC1 in a mixture with Me20.213 Miscellaneous.-Papers from the 1971 symposium on tritium have been published during 1973. Commercial y-aluminas containing traces of iron can, after treatment with aqueous alkali, bring about the dissociation of H, and catalyse olefin hydrogenation at and above room temperat~re.'~'Trapped hydrogen atoms were found to be produced when HI-[2H1,]3-methylpentane was photolysed (254 nm) at less than 50 K."" The rate constant at 86K for the formation of H: (or D:) has been measured using a high-pressure mass ~ p e c t r o m e t e r .Comparison ~~~ of the result with that at 300K indicates that the reaction:
has an apparent activation energy of -1.5 kcal mol-' 212 *I3 214
215
21a
'Iy
G. J. Jiang and G. R. Andersson, J. Chem. Phys., 1974, 60, 3258. R. Yamdagni and P. Kebarle, Canad. J. Chem., 1974, 52, 2449. A. S. Gilbert and H. J. Bernstein, Canad. J. Chem., 1974, 52, 674. M. Arshadi, R. Yamdagni, and P. Kebarle, J. Phys. Chem., 1970, 74, 1475. J. D. Payzant, R. Yamdagni, and P. Kebarle, Canad. J. Chem., 1971, 49, 3308; R. Yamdagni, J . D. Payzant, and P. Kebarle, ibid., 1973, 51, 2507. M. Arshadi and P. Kebarle, J. Phys. Chem., 1970, 74, 1483. P. A. Sermon, G. C. Bond, and G. Webb, J.C.S. Chem. Comm., 1974, 417. L. Perkey and J. E. Willard, J. Chem. Phys., 1974, 60, 2732. R. C. Pierce and R. F. Porter, Chem. Phys. Letters, 1973, 23, 608.
8 The Noble Gases ~~
BY M.
F. A. DOVE
1 The Elements The results of LCAO-SCF-MO calculations of the ground states of He,H and He,H+ clusters (n = 1-4) have been published:' the relative stabilities of the various complexes were explored and some preliminary calculations carried out on excited states. The significance of the results for the unusual i.r. spectra reported by Bondybey and Pimentel for hydrogen-rare gas matrices was discussed. The polarity of a number of loosely bound (van der Waals) complex molecules has been measured qualitatively by molecularbeam electric deflection:' among the polar molecules are Ar,NO, Ar,HCl, Ne,DCl, Xe,HCl, Ar,BF,, and Kr,BF,. R.f. and microwave spectra of K = 0 states of Ar,HF in the ground vibrational state have been measured by molecular beam electric resonance ~pectroscopy.~ From the centrifugal distortion constant, the stretching frequency of the van der Waals' bond was estimated to be 42 cm-I: the equilibrium configuration is likely to be linear. An apparatus consisting of four diffusion chambers, each of which has a PTFE diaphragm, has been constructed4 for testing the separation of the noble gases and, hence, for the recovery of radioactive noble gases (e.g. 85Kr)from reactor gases. The potential radio!ogical health effect from 222Rn in natural gas has been r e ~ i e w e d .The ~ problem arises particularly when natural gas is used in unvented appliances; this could potentially lead to a small number of deaths from lung cancer because of the inhalation of the (Y -emitting daughter products. A process for the removal of these radiochemicals from air has been patented.6 The dried air is decontaminated after passage through either a solution of a powerful fluorinating agent, such as ClF, or K2NiF6,or a bed of solid complex fluoride, such as ClF,,SbF, . M. B. Milleur, R. L. Matcha, and E. F. Hayes, J. Chem. Phys., 1974, 60, 674. S. E. Novick, P. B. Davies, T. R. Dyke, and W. Klemperer, J. Amer. Chem. Soc., 1973, 95, 8547. S. J. Harris, S. E. Novick, and W. Klemperer, J. Chem. Phys., 1974, 60, 3208. T. Maekawa and T. Ishimori, Genshiryoku Kogyo, 1974, 20, 36. R. H. Johnson, D. E. Bernhardt, N. S. Nelson, and H. W. Cally, Gout. Rep. Announce. (U.S.), 1974, 74, 59. L. Stein, U.S. P. 3 778 499 (Chem. Abs., 1974, 80, 87 103j); L. Stein, S. Afr. P. 7 205 639 (Chem. Abs., 1974, 80, 73 901f).
495
496
Inorganic Chemistry of the Main- group Elements 2 Krypton, Xenon, and Radon(@
Contour plots of the valence-shell MO’s of KrF, have been determined from ab initio calculation^;^ the results are consistent with the use of three atomic pa orbitals for the four-electron three-centre a-bonding. The experimentally determined xenon 3d electron binding energies in XeF, and other xenon compounds are less than half those predicted by ab initio pointcharge calculations.* This was taken as possible evidence for F-to-Xe T back-bonding and for orbital independence in the Xe-F bonding. Adducts of KrF, with strong fluoride-ion acceptors have been prepared and characterized for the first time. KrF, forms 2 : l adducts with SbF,”.’”and AsF,1° which should be formulated as [Kr2F3]+[MF6]-on the basis of Raman and 19 F n.m.r. spectroscopy; the antimony compound decomposes very slowly in a dynamic vacuum at -30 “C to give the 1:1 adduct, [KrF]+[SbF,]-, under which conditions it is stable to 35 “C.” Other 1:1 adducts were isolated with AsF, and PtF,, as well as 1:2 adducts with SbF, and AsFS.’*Either of the cationic krypton(r1) species is capable of oxidizing BrF, to [BrF,r, which could be isolated as the [AsFJ or [Sb,F,,]- salts.1o”’ XeF, may be separated from the other xenon fluorides by g.1.c.;” the technique has been applied for both analytical and preparative purposes. The same group of have demonstrated that combined S, Se, and Te can be determined by means of the reaction gas chromatograph, in which XeF,, diluted with helium, reacts with them at ambient temperature to form volatile fluorides, which can then be separated. Catalysis by [MnFJ- derivatives of the thermal reaction between Xe and F, at 120°C has been in~estigated:’~ the reaction is first-order in the Xe concentration and zeroth-order with respect to F,. The oxidation of xenon to [XeF]’ by [BrF,]’, which is itself generated by KrI’ cations,ll demonstrates the relative fluorinating ability of these two noble gases in the +2 state. The heats of hydrolysis of XeF,,MF,, XeF,,2MFs (M=Sb, Ta, or Nb), and 2XeF2,MFs (M=Sb or Ta) have been measured and used to calculate the enthalpies of formation of these adducts.” The results confirm that the degree of ionic character in a given series of adducts increases along the series Nb