4 0,S Se Te By F. J. BERRY Department of Chemistry The Open University Walton Hall Milton Keynes MK7 6AA 1 Introduction Interests in the technologically important properties of chalcogen-containing solids have continued to grow and this has been reflected in the development of programmes of work seeking to make useful materials by new techniques and characterize their structural and physical properties. This is well illustrated by the attention which has been given to high temperature superconductors where the materials of interest are inorganic oxides. The attempts to make new materials by new routes and thence characterize structural properties which are related to the critical temperatures has resulted in the development of a significant literature on this topic.It is therefore no longer appropriate to review this subject in a chapter devoted to the chemistry of the chalcogens and the reader is referred to chapter nine in this Report where the important developments in this area of science are reviewed in detail. 2 Oxygen Dicopper(1) complexes of tpmc [1,4,8,1l-tetrakis (2'-pyridylmethyl)-l,4,8,1l-tetra-azacyclotetradecane] have been synthesized and found' to react with dioxygen at low temperatures (below -60°C). The reactions were shown to form two species of adduct quasi -reversibly and the resulting compounds were characterized by Resonance Raman spectroscopy. The studies are relevant to current interests in the copper-containing metalloproteins called haemocyanins which bind and transport dioxygen in the haemolymph of molluscs and anthropods.The reaction of dioxygen with low-spin five coordinate complexes PFe"'Ar (P = porphyrin dianion and Ar = aryl group) have also been examined and the formation of aryloxy-iron(II1) and aryl-iron( IV) complexes have been described.2 The chemistry and reactivity of the superoxide ion (02'-) has continued to attract attention because of its appearance as a respiratory intermediate and its role as an effective nucleophile in aprotic media. This is illustrated by a study3 of the addition of excess hydroxide ion to dioxygen-saturated dimethyl sulphoxide solutions con- taining aniline which showed the reaction to give two superoxide ions one azoben- zene and one hydrogen peroxide per two aniline molecules. Similar stoichiometries and yields of O2 were achieved with the N-substituted anilines but PhNHNH2 ' E.Asato S. Hashimoto N. Matsumoto and S. Kida J. Chem. SOC. Dalton Trans. 1990 1741. * R. D. Arasasingham A. L. Balch R. L. Hart and L. Latos-Grazynski J. Am. Chem. SOC.,1990,112,7566. S. Jeon and D. T. Sawyer Inorg Chem. 1990. 29 4612. 45 46 F.J. Berry and some other substrates gave lower yields of O2 . Mechanisms for the sub- strate/-OH reduction of 0 via electron-transfer steps were proposed. The oxygen atom transfer reactions of peroxo- and diperoxo-complexes of oxovanadium( v) with (en)2Co( SCH2CH2NH2)2+ have been ~tudied.~ The d'-d' dimers[MO{S2CN-(CH2Ph)2},),0] (M = Mo W) which contain a linear 0x0 bridge have been shown' to photodisproportionate and evidence has been found for oxygen atom transfer from the compound [W02{S2CN(CH2Ph)2}2] to PEt,.The reactions of [ho(NPPh,NPPh21h)C13] with Ph3SiOH and Bu'OH have been found6 to lead to exchange and rearrangement reactions in which the nitrogen atoms which coordinate molybdenum are replaced by oxygen. The crystal struc- turss of [dlo(OPPh,NHPPh2~)O2Cl2] [dl~(OPPh~NPPh~d)~(o)cl], and [dlo(OPPh,NPPh2d202] were reported together with the synthesis of these unexpec- ted products by more direct routes. Stable tris(dimeth1yamino)sulphonium salts of the perfluoroalkoxides FC(0)(CF2),CF20-( n = 0 1,3) and -OCF2(CF2),CF20- (n = 1,3) have been synthesized and characterized.' The C2F3O2- anion generated from oxalyl fluoride has been shown to have an open ground-state structure and not a bridged-fluoride structure as previously proposed.3 Sulphur Theoretical studies of the potential energy surface of the poorly understood allotrope of elemental sulphur S4 have been performed by use of ab inito electronic structure theory.* Sulphur-nitrogen compounds have continued to attract attention. The 14N NMR spectra of a variety of sulphur-nitrogen heterocycles and metal-sulphur-nitrogen complexes have been recorded and the observed shifts correlated with bonding type.' The study is a good illustration of the utility of 14N NMR spectroscopy as a mechanistic tool in sulphur-nitrogen chemistry for reactions in liquid ammonia. The synthesis and electrochemistry of palladium and platinum macrocyclic com- plexes of [181ane N2S4( 1,4,10,13-tetrathia-7,16-diazacyclooctadecane)and Me2 [18lane N,S4-(7,16-dimethyl-1,4,lO,l3-tetrathia-7,l6-diazacyclooctadecane)have been described." The compound S4N402 has been shown" to react with [MCl,(PR,),] in liquid ammonia to produce [M{S2N3(S02NH2)} (PR3)2] (M = Pt PR = PMe2Ph PMePh, PEt, PPr3" or PBu,"; Me = Pd PR = The 4-phenyl-1,2,3,5-dithiadiazole iPh2PCH2CH2PPh2).dimer has been found" to dehalogenate [SSN5]C1 by a novel ring contraction which produces [(Ph( N2S2)2C1]- [S3N3] in acetonitrile and a mixture of [(PhCN,S,),Cl][S,N,] and [PhCN2S2][S3N3] in pentane. The structural properties of the products were described. A. F. Ghiron and R. C. Thompson Inorg. Chem. 1990 29 4457. S. Lee D. L.Stoley A. L. fieingold and N. J. Cooper Inorg. Chem. 1990 29 4391. M. Rietzel H. W. Roesky K. V. Katti H.-G. Schmidt R. Herbst-Irmer M. Nolterneyer,G. M. Sheldrick M. C. R. Syrnons and A. Abu-Raqabah J. Chem. SOC.Dalton Trans. 1990 2387. ' D. A. Dixon W. B. Farnham and B. E. Smart Inorg. Chem. 1990 29 3954. G. E. Quelch H. F. Shaefer and C. J. Marsden J. Amer. Chem. SOC.,1990 112 8719. I. P. Parkin J. D. Woolins and P. S. Belton J. Chem. SOC.,Dalton Trans. 1990 511. 10 A. J. Blake G. Reid and M. Schroder J. Chem. SOC.,Dalton Trans. 1990 3363. I. P. Parkin and J. D. Woolins J. Chem. SOC.,Dalton Trans. 1990 519. 12 A. J. Banister M. I. Hansford Z. V. Hauptrnan A. W. Luke S. T. Wait W. Clegg and K. A. Jorgensen J. Chem. SOC.,Dalton Trans. 1990 2793. 0 S Se Te Hyperfine coupling parameters for coordinating nitrogen atoms in some copper( 11) complexes with planar and tetrahedrally distorted N2S2 coordination structures have been rep~rted.'~ Studies relevant to current interests in the active site of nickel- containing hydrogenases have identified14 an example of sterically protected Ni2+ in a N2S2 donar environment in 1,5-bis(mercaptoethyl)-1,5-diazacylooctane and its methylated derivative.The preparation of the binuclear complex [Pt(1,5-Ph4P2N4S2)(PPh3)I2 in which the dithiatetrazocline ligand exhibits a novel bonding mode has been rep~rted'~ (Figure 1). Figure 1 Structure of [Pt( 1,5-Ph4P2N4S2)( PPh,)] (Reproduced by permission from Inorg. Chern. 1990 29 3068) The P2N4S2 rings were shown by X-ray crystallography to act as chelating (N S) ligands toward one platinum and to form a bridge to the second platinum via the other sulphur atom and thereby give a centrosymmetric dimeric structure.The sulphur atoms were both shown to be three-coordinate and trans to each other and the Pt-S bond lengths were found to be equal. The variable temperature 31P NMR spectra recorded from the compound showed it to be the first example of a metal- lotropic rearrangement in coordination complexes of S-N ligands (Figure 2). The structure of 1,3,2-benzothiazolium chloride sulphur dioxide solvate C6H4S2N+C1-*S02 has been shown16 to consist of discrete planar cationic units chloride anions and SO molecules. Significant contacts were found to exist between the anion and the SO2 molecule (implying some (SO,Cl-) character) and the sulphur centres of the cation such that the solvate adopted a two-dimensional polymeric macrostructure.The centrosymmetric 1,3,2-benzodithiazolyl dimer was shown to contain two C6H4S2N units joined by two long S-S bonds [3.175(1) A] with interplanar spacings of 3.0A between the two c6s2 mean planes (Figure 3). The dimers were found to be linked by very weak S...S contacts into a sheet-like l3 R. Miyamoto Y. Ohba and M. Iwaizumi inorg. Chem. 1990 29 3234. 14 D. K. Mills J. H. Reibenspies and M. Y. Darensbourg Inorg. Chem. 1990 29,4364. Is T. Chivers M. Edwards P. N. Kapoor A. Meetsma J. C. van de Grampel and A. van der Lee Inorg. Chem. 1990 29 3068. 16 E. G. Awere N.Burford R. C. Haddon S. Parsons J. Passmore J. V. Waszczak and P. S. White Inorg. Chem. 1990 29 4821. F. J. Berry PhqP PPh3 Ph3P \ PPh3 Figure 2 Proposed mechanism for the [1,3]-metallotropic rearrangement in [Pt(1,5-Ph4P2N4S2)-( PPh 112 (Reproduced by permission from Znorg. Chem. 1990 29 3068) \3*175(1) Figure 3 Centrosymmetric (C,H,S,N') (Reproduced by permission from Inorg. Chem. 1990 29 4821) infinite two dimensional net. Variable temperature magnetic susceptibility measure- ments showed the solid to be essentially diamagnetic but on melting to become paramagnetic. A new preparative route to salts of the SNS+ cation has been described" which should lead to a wide variety of other SNS+ salts. The method involves the reaction of tin(I1) chloride with N(SCl),'X-(X = AIC14 or SbC16) in liquid sulphur dioxide or CH2C1 to give high yields of SNS+X- and tin(1v) chloride." A. J. Banister and J. M. Rawson J. Chem. Soc. Dalton Trans. 1990 1517 0,S Se Te A very low first oxidation potential of 0.15 V us SCE has been foundI8 to characterize the 12~-electron compound 4,7 dimethyl-4,7dihydro[ 1,2,5]thia- diazolo[3,4-b] pyrazine (Figure 4(a)) which was formed by reduction of the corre- sponding 14n-electron system with potassium and trapping of the dianion with methyl iodide. The compound was shown to react with the electron acceptor shown in Figure 4(b) to give conducting charge transfer complexes (a= 5.6 x 1.OP2 cm-I). (a) (b) Figure 4 (a) 4,7-dimethyl-4,7-dihydro[ 1,231 thiadiazolo [3,4-b] pyrazine and the electron acceptor (b) which gives on reaction conducting charge transfer complexes (Reproducedby permission from Angew.Chem. In?. Ed. Engl. 1990 29 643) The combination of pyridine ligands [NCI,Tc]-and dithionite has been found" to result in the transfer of a sulphur atom to the coordinated nitride and a net five-electron reduction of the Tc to give mer-[(SN)C12( Py),Tc]. Phosphorus-sulphur compounds have also continued to attract attention. The vapour from solid molecular tetraphosphorus decasulphide P4S10 has been examined,' by infrared spectroscopy after trapping in solid argon and shown to contain P4S10 and P4S9. Other phosphorus sulphides (PS PS2) and diphosphorus sulphides (P2S4 P,S,) were also identified.Photolysis of P4S10 and O3 mixtures gave P4S90 and SO,. The kinetics of the redox dissocation of P4S10 dissolved in 1-chloronaphthalene has been studied21 at temperatures between 110 and 150 "C. The phosphorus-containing reaction products inclduded P4S9 and smaller amounts of phosphorus polysulphides. The initial kinetics were described as quasi first order and were unaffected by dilution. The reaction was found to be insensitive to the presence of oxygen and to the addition of sulphur but to be catalysed by the presence of iodine- and bromine-containing compounds. A mechanism involving the initial rate determining fission of P4S10 into two molecules of metastable P,S was proposed. Photolysis of the P4S3.-.03 molecular complex in solid argon with red light has been shown2 to produce two sets of new infrared absorptions which were assigned as terminal PO and symmetric P-S-P stretching modes.These were associated with structural isomers of P4S30 containing terminal oxygen at the apex and base phosphorus positions. Further ultraviolet photolysis gave evidence for the formation of 0x0-bridged P4S30 and a secondary product of composition P4S302. in Y. Yamashita J. Eguchi T. Suzuki C. Kabuto T. Miyashi and S. Tanaka Angew. Chem. fnt. Ed. Engl. 1990 29 643. 19 J. Lu and M. J. Clarke fnorg. Chern. 1990 29 4123. 20 L. Andrews G. C. Reynolds 2.Mielke and M. McCluskey fnorg. Chem. 1990 29 5222. 21 M. C. Dtmarcq J. Chem. Soc. Dalton Trans. 1990 35. 22 Z. Mielke L. Andrews K. A. Nguyen and M.S. Gordon Inorg. Chem. 1990 29 5096. 50 F. J. Berry A novel approach to the synthesis of ring systems containing phosphorus nitrogen and sulphur which takes advantage of the known susceptibility of N-S(Ph) bonds to homolytic cleavage has been described.23 Experimental evidence for the compar- able strength of P-S P-N pr-bonding within the heteronaphthalenic framework has been pre~ented,~ in a report on the spectroscopic and structural properties of the 1,3,2-benzazathuaphospholium system. Phosphorus-3 1 nitrogen-15 and nitrogen-14 NMR studies of a-tetraphosphorus trisulfide isothiocyanates have been reported.25A series of compounds with the general formula R,PE.AlCl (R = Ph or NMe, E = S or Se) have been examined26 by NMR spectroscopy and the results interpreted in terms of the nature of the P-E bond and the character of co-ordinate bonding in the compounds.The molecular structures of gaseous bis(methylsily1)sul- phide and bis(dimethylsily1)sulphide have been determined by electron diffra~tion.,~ The synthesis and characterization of new layered M'M"'P2S6 phases which are well known to exhibit interesting physical properties has continued to attract atten- tion. This is illustrated by the reported2* preparation of single crystals of cuvP& by heating the elements in an evacuated silica tube at 500°C. The compound was found to adopt the M,"P,S,-type structure in which the copper(1) ions fail to occupy every other M'' octahedron (as was observed for the vanadium(II1) cations) but to be distributed on three different crystallographic sites inside and outside the octahedra.A nickel K-edge EXAFS study of lithium-intercalated layered NiPS with various lithium contents has been reported.29 The large modifications in the EXAFS spectra were related to the displacement of reduced nickel atoms from their initial octahedral sulphur sites to tetrahedral sites within the slabs. The intercalation of ferrocene into layered Cd2P2S6 has been achieved by reacting the cobaltacene- intercalated Cd,P2S6 with ferr~cene.~' Incommensurate misfit layer structures of the type MTS3 (M = Sn Pb Bi rare earth elements; T = Nb Ta) have been studied by electron diffraction and high resolution electron micro~copy.~' Single crystals of the n-type semiconducting tin dichalcogenides SnS,-,Se (x = 0,0.3,0.5,1.3 1.85 2) which have a two-dimensional layered structure have been intercalated3 with cobaltocene to give the series of compounds SnS2-,Se (CoCp,),,, (Cp-q5-C5H5).X-Ray photoelectron spectroscopy showed mixed oxidation states for both tin [Sn" Sn'"] and cobalt [Co' Co" Co"']. TWO of the cobalt species were identified as CoCp and [CoCp2]+ and the third tentatively assigned to a Co( qs-C5H5)( q4-CsH5R) complex in which cobalt is formally in the oxidation state Cot (Figure 5). Ultraviolet photoelectron spectroscopy showed the 23 T. Chivers S. S. Kumaravel A. Meetsma J. C. van de Grampel and A. van der Lee Inorg. Chem. 1990 29 4591. 24 N. Burford A. I. Dipchand B. W. Royan and P. S. White Inorg. Chem.1990 29 4938. 25 B. W. Tattershall J. Chem. SOC.,Dalton Trans. 1990 663. 26 N. Burford B. W. Royan R. E. v. H. Spence and R. D. Rogers J. Chem. Soc, Dalton Trans. 1990,2111. 27 D. G. Anderson V. A. Campbell G. A. Forsyth and D. W. H. Rankin J. Chem. SOC.,Dalton Trans. 1990 2125. 28 E. Durand G. Ouvrard M. Evain and R. Brec Inorg. Chem. 1990 29 4916. 29 G. Ouvrard E. Prouzet R. Bred S. Benazeth and H. Dexpert J. Solid State Chem. 1990 86 238 30 G. T. Long and D. A. Cleary J. Solid State Chem. 1990 87 77. 31 S. Kuypers J. van Landuyt and S. Amelinckx J. Solid State Chem. 1990 86 212. 32 C. A. Formstone. E. T. Fitzgerald P. A. Cox and D. O'Hare Inorg. Chem. 1990 29 3860. 0 S Se Te LLs A .Sn 0S Figure 5 Representation of the possible Cot organocobalt species between the SnX layers (Reproduced by permission from Inorg.Chem. 1990 29,3860) intercalates to be either semiconducting (x = 0 0.3 0.5 1.3) or metallic (x = 1.85 2). The preparation structural properties and conductivities of Li2SiS3 phases has been described.33 The compound Na,S has been ~ynthesized~~ by a new solid-gas reaction of Na2C03 with a sulphidizing gas mixture and by a solid-solid reaction of carbon with Na2S04. Two new crystal modifications of Na2S were identified by X-ray powder diffraction in addition to the previously reported antifluorite structure. The structure of CoGaInS has been determined from single crystal X-ray diffraction data and to adopt the FeGa,S layer type structure.The chemistry and thermodynamics of solid and vapour phases in the technologic- ally important Bas-Ga2S3 system has been studied.36 The results were interpreted in terms of a generalized acid-base theory in which solid Bas was considered as a strong base arid solid Ga2S3 as an acid. Chemical interactions in the quasibinary CaS-Ga,S system have also been examined37 by differential thermal analysis X-ray diffraction and microstructural analysis. The thiogallate formation was identi- fied as CoGa2S4 which was found to crystallize as an orthorhombic compound. The structural modifications arising from the addition of various sulphides and oxysul- phides to a'Ga2S3 have been in~estigated.~~ The compounds Cu2GeS3 Cu2SiS3 and Cu2SiSe3 have been dissolved in the ternary compound CuGe2P3 and by use of a modified Bridgman technique have enabled good quality single crystals of single phase compounds to be grown.39 A complete solid solution series in the 33 B.T. Ahn and R. A. Huggins Mat. Res. Bull 1990 25 381. 34 M. Kizilyalli M. Bilgin and H. M. Kizilyalli J. Solid State Chem. 1990 85 283. 35 H. Haeusler H. J. Stork and W. Cordes J. Solid State Chem. 1990 87 15. 36 P. Mukdeeprom-Burckel and J. G. Edwards Mat. Res. Bull. 1990 25 163. 37 N. I. Yagubov T. N. Guliev P. G. Rustamov and E. T. Azizov Mat. Res. Bull. 1990 25 271. 38 M. Guittard M. P. Pardo and A. Chilouet Mat. Rex Bull. 1990 25 563. 39 M. S. Omar Mat. Res. Bull. 1990 25 691. 52 F. J. Berry system CuGe2P3 -Cu2GeS3 was identified.The compound CuGe2P3 failed to form any solid solution with Cu2SiS3 and Cu2SiSe3. The compound In,oSn6S2 has been shown4' to contain octahedrally coordinated In3+ with the Ins octahedra forming layers. The tin(I1) species were shown to occupy trigonal dicapped prismatic sites between the layers. The spinel structure I~,&I,S~~ has been chemically lithiated with n-butyl lithium and the redox processes and structural analysis examined4' by '19Sn Mossbauer spectroscopy and 7Li NMR. 119 Sn Mossbauer spectroscopic studies of the a-and /3 forms of Lr~,,Sn,s~~ were subsequently described.42 Structure field maps for ternary sulphides crystallizing in common AB2X4 structures have been described43 and used to predict possible compositions for new quaternary compounds of the ZnIn2S4 type.Some antimony chalcogenides with lone pairs of electrons have been examined by 121Sb Mossbuer spectroscopy.u The increase in the chemical isomer shift with increasing covalency and distortion of the local antimony environment was quantita- tively explained by a tight-binding band-structure calculation. The structural proper- ties of the Sb2S3-SbBr3-SbI and Sb2S3-PbBr2-PbI glass systems have been investigated by infrared absorption studies45 and interpreted in terms of SbS3 pyramids which are more or less polymerized and connected to various thiohalide antimony or lead entities. A correlation between structure and optical properties was proposed for the Sb2S3-PbBr2-Pb12 glasses. Percolation phenomena have been reported46 during the transition from an ex- plosive to nonexplosive mechanochemical synthesis of some metal chalcogenides.The structure of silver-intercalated titanium disulphide Ag0.167TiS2 has been determined at several temperatures from time-of-flight neutron powder diffraction data47. The results are relevant to current interests in staging pheomena in lamellar transition metal dichalcogenides. The structures of a range of solid solutions of composition Li,Cuo,07Ti2,05S4 formed by intercalating lithium into the host com- pound CU~,~~T~~,~~S~ have been described4' and related to the structure of spinel. The materials are of interest as cathodes in lithium batteries. A new composite- layered sulphide of composition ( PbS)1,12VS2 'PbVS3' has been prepared49 and shown to consist of two kinds of mutually stacked layers.The material of composition (CeS)1,16NbS2 has been shown5' to be a misfit layer compound built of alternate double layers of CeS approximately a (100) slice of NaC1-type CeS and sandwiches of NbS2 in which niobium adopts a slightly distorted trigonal prismatic site. The compound showed metallic conduction properties with 40 A. Likforman M. Guittard and F. Robert J. Solid State Chem. 1990 89 275. 41 M. L. Elidrissi-Moubtassim J. Olivier-Fourcade J.-C. Jumas and J. Sonegas J. Solid Stare Chem. 1990 87 1. 42 M. L. Elidrissi-Moubtassim J. Olivier-Fourcade J.-C. Jumas and M. Maurin J. Solid State Chem. 1990 87 274. 43 H. Haeuseler J. Solid State Chem. 1990 86 275.44 J. Olivier-Fourcade A. Ibanez J. C. Jumas M. Maurin 1. Lefebvre P. Lippens M. Lannoo and G. Allen J. Solid State Chem. 1990 87 366. 45 J. J. Videau B. Tsobgny J. Portier B. Tanguy and P. Hagenmuller Mat. Rex Bull. 1990 25 231. 46 V. Rusanov and Chr. Chakurov J. Solid State Chem. 1990 89 1. 47 G. L. Burt V. G. Young M. J. McKelvy W. S. Glaunsinger and R.B. Von Dreele J. Solid Stare Chem. 1990,84 355. 48 Y. Saidi I. Abrahams and P. G. Bruce Mat. Rex Bull. 1990 25 533. 49 Y. Gotoh M. Goto K. Kawaguchi Y. Oosawa and M. Onoda Mat. Rex Bull. 1990 25 307. 50 G. A. Wiegers A. Meetsma R. J. Haange and J. L. De Boer J. Solid State Chem. 1990 89 328. 0,S Se Te 53 a strong anisotropy. The metal-rich sulphide Ta6,0sNb4,92S4 has been prepared by high temperature techniques and shown to adopt a structure which is more similar to that of niobium-rich sulphides than tantalum-rich ~ulphides.~’ The structure of (LaS)1,14NbS2 has been re-examined5 through a supercell approach using a non- centrosymmetric space group instead of the centrosymmetric one previously reported.Resistivity measurements made on single crystals indicated a metallic behaviour and a transition to a superconducting state below T = 2.43 K. A detailed study of the reactivity of niobium pentachloride with three different organic sul- phurizing agents (CH3)3SiSSi(CH3)3 (CH3)3CSSC(CH3)3 and (CH3)3CSC(CH3)3 has showns3 that the organic agent does not affect the Nb/S ratio of 2.5 in the amorphous niobium sulphide which is formed.The amorphous product was found to be very reactive and to rapidly convert to a crystalline niobium sulphide by heating at high temperature. Single crystal X-ray diffraction of SnTaS at 295 K and 425 K has the unusal linear coordination of tin by sulphur in the neighbouring TaS sandwiches. A new barium tantalum sulphide of composition Ba2TaS5 has been prepared55 by the reaction of CS with a mixture of BaCO and Ta205 and shown to be isostructural with Ba2NbS5. The compound of formula (PbS)1,13TaS2 which was formerly desig- nated ‘PbTaS,’ has been found56 by single crystal X-ray diffraction to be a misfit layer compound characterized by two face-centered orthorhombic unit cells. One was shown to belong to the PbS part of the structure and the other to the TaS part.The compound was shown to be built of alternately double layers of PbS with distorted NaC1-type structure and TaS sandwiches with tantalum in distorted trigonal prisms of sulphur. X-Ray photoelectron spectroscopy and polarized neutron diffraction has been used” to investigate chemical bonding and ion valencies in the ferromagnetic metallic copper chromium chalcogen spinels CuCr2X4. The result showed the presence of trivalent chromium monovalent copper and one hole in the anion valence band per formula unit i.e. Cu+(Cr3+),(S2-),(S*+).The tetrathiometalates [MS4I2- are well known as fundamental structural and reactive entities in transition metal sulphide chemistry and it is therefore notable that new routes of entry to the solution chemistry of niobium- and tantalum-sulphides have led5* to the synthesis of soluble forms of [MS4I3-.Molybdenum- and tungsten-sulphur compounds have continued to attract atten- tion. A method for the chemical deposition of thin films of semiconducting MoS2 and MoSe on glass substrates using sodium dithionite as a reducing agent has been described59. The morphological structural optical and electrical properties of molybdenum sulphide thin films deposited on a glass substrate by simple chemical 5’ X. Yao and H. F. Franzen J. Solid State Chem. 1990 86 88. 52 A. Meerschaut P. Rabu J. Rouxel P. Monceau and A. Smontara Mat. Res. Bull. 1990 25 855. 53 A. Bensalem and D. M. Schleich Mat. Res. Bull. 1990 25 349. 54 A. van der Lee and E. A. Wiegers Mat.Res. Bull. 1990 25 1011. 55 M. Saeki and M. Onoda Mat. Res. Bull. 1990 25 723. 56 J. Wulff A. Meetsma S. van Smallen R. J. Haange J. C. De Boer and G. A. Wiegers J. Solid State Chem. 1990 84 118. 57 A. Payer M. Schmalz R. Schollhorn R. Schlogl and C. Ritter Mat. Res. Bull. 1990 25 515. 58 S. C. Lee and R. H. Holm J. Am. Chem. Soc. 1990 112 9654. 59 S. Pramanik and S. Bhattacharya Mat. Res. Bull. 1990 25 15. 54 E J. Berry methods using molybdenum( VI) ions ammonia hydrazine hydrate and thioacetamide has also been described.60 Model-promoted and sulphur-deficient molybdenum disulphide-based catalysts have been prepared and tested for the hydrosulphurization of thiophene.61 X-Ray diffraction and electron microscopy showed the active catalysts to possess a high degree of disorder in directions representing the edges of the MoS2 crystal.Both Group VIII promotion and sulphur deficiency were found to give similar structural changes in the molybdenum sulphide lattice which could be correlated with increased catalytic activity. The kinetics of the 1:1 complexing of NCS- for H20 substitution at tungsten on the incomplete cuboidal W3IVclusters [W3(p3-S)(p-S)3(H20)9]4+ and [W3(p3-S)(p-O)3(H20)9]4+ has been investigated62 and together with data from [W3(p3-0)(p-O),(H20)J4+ has been used to elucidate the reactivity pattern for the [W30,S4-x( H,0),I4+ series of p-oxo/p-sulphido aqua ions. New fluxional seven-co-ordinate molybdenum( 11)-and tungsten( 11)-complexes have been prepared63 and the structure of the pyridine-2- thionato complex described.The oxidation of sulfur( IV) by dodecatungstocobal- tate(111) in aqueous acid solution has been in~estigated.~~ A variety of manganese( I) carbonyl complexes containing triethylphosphine and monodentate or chelate triethylphosphoniodithiocarboxylato ligands have been obtained by substitution reactions either under mild conditions or by thermal or photochemical methods.65 The products resulting from the thermal reactions between bromo carbonyls and S2CPEt3 were found to be very different from those obtained with S2CP(C6H1,)3 under similar conditions as a result of the electronic and steric differences between the phosphines concerned. The preparation properties and reactions with sulphur dioxide of triphenylphosphine oxide complexes of manganese( 11) thiocyanate have been reported.66 Interests in iron-sulphur proteins have continued to generate considerable activity in studies of compounds containing iron and sulphur.A new series of Fe4S4 active-site analogues for high-potential iron-sulphur proteins have been prepared from [Fe4S4( SBU')~],- and macrocylic tetra-aza tetrathiol ligands where the active site cores are composed of an intramolecular hydrophobic domain formed by 28- 32- 36- 40- and 42-membered rings with methylene backbone^.^' A new type of active site analogue for 4Fe-4S iron-sulphur proteins has been formed in which the active site core is surrounded by an intramolecular hydrophobic domain formed by a 36-membered ring consisting of a methylene backbone.68 The magnetic suspectibility of the high potential protein model [Fe4S4(S-2 4,6-(Pri)&H2)4]- in the [Fe4S4I3+ oxidized state has been examined69 over the temperature range 5-320 K.The 57Fe Mossbauer spectra of salts containing the anions [Fe4S4( SBu'),12- or [FeX,l2-6o K. C. Mandal and A. Mondal J. Solid State Chem. 1990 85 176. 61 A. Sachdev J. Lindner J. Schwank and M. A. Villa Garcia J. Solid State Chem. 1990 87 378. 62 M. Nasreldin A. Olatunji P. W. Dimmock and A. G. Sykes J. Chem. Soc. Dalton Trans. 1990 1765. 63 A. J. Deeming M. Karim and N. I. Powell J. Chem. Soc. Dalton Trans. 1990 2321. 64 M. Ali S. K. Saha and P. Banerjee J. Chem. Soc. Dalton Trans. 1990 187. 65 D. Miguel V. Riera J. A.Miguel F. Diego C. Bois and Y. Jeannin J. Chem. Soc. Dalton Trans. 1990 2719. 66 K. Al-Farham B. Beagley 0. El-Sayrafi G. A. Gott C. A. McAuliffe P. P. MacRory and R. G. Pritchard J. Chem. Soc. Dalton Trans. 1990 1243. 61 T. Tomohiro K. Uoto and H. Okuno J. Chem. Soc. Dalton Trans. 1990 2459. 68 H. Okuno K. Uoto T. Tomohiro and M.-T. Youinou J. Chem. Soc. Dalton Trans. 1990 3375. 69 J. Jordanov E. K. H. Roth P. H. Fries and L. Noodleman Inorg. Chem. 1990 29. 4288. 0 S Se Te 55 (X = C1 or Br) have been interpreted in terms of perturbations exerted by the cations on the field gradient at the iron centres.70 The [Fe4S4(Me2LS3)L’I2-(L’ = RS-,Cl-) clusters have been shown7’ to contain the cubane-like [Fe4S4I2+ core and to be derived from the trithiol Me,L(SH) (L = 1,3,5-tris((4,6-dimethyl-3-mercap-tophenyl)thio)-2,4,6-tris(p-toly1thio)benzene) which as the trianion functions as a semirigid tridentate ligand.The clusters were shown to be analogous to some biological clusters which undergo regiospecific reactions at differentiated iron sites. The cubane-type cluster [Fe,S,( LS3)C1I2- (LS3 = tris[ (4,6-dimethyl-3-mercapto-phenyl)thio]-2,4,6-tris( p-tolylthio) benzene (3-)] has been shown72 to contain iron differentiated in the ratio 3 :1.The cluster was found to undergo substitution reactions at the unique sub-site with stoichiometric cyanide and excess isonitrile in acetonitrile solution to give [Fe4S4(LS,)(CN)]2- and Fe,S4(LS3)(RNC)3]‘- (R = Me Et But C6Hll and 2,6-Me2C,H3). The 57Fe Mossbauer spectra recorded from some deriva- tives demonstrated the existence of a low-spin Fe2+ subsite assigned to the trigonal Fe( RNC) group and a spin-isolated [Fe3S4I0 cluster fragment having the same ground-state electronic structure as singly reduced 3Fe clusters of proteins.In continued studies of nitrogenase substrates the synthesis and characterization of two new doubly bridged double cubanes of the type [[MoF~~S~C~~(C~~,,,)]~ (p2-S) (p2-L)]”- (L = N2H4 n = 4; L = CN- n = 5) which contain Mo-(p2-L)-Mo bridges with the biologically relevant N2H4 ligand and CN- have been reported73 (Figure 6). Figure 6 Preliminary structure of the anion core in [E~,N],[[MOF~,S~C~~(C~~~~)]~( pz-S)-(P2N2H4)IChCN (Reproduced by permission from J. Am. Chem.Soc. 1990 112 8606) The structure of the compound [MoFe,S4( Me2dtc)J2CH2C12 has been deter- mined74 and shown to contain a cubane-like [MoFe3S4I5+ core. Three new cluster complexes (Et4N)3[ Re2Fe,S,( SEt),] (Et4N)2[Re2Fe7S,(SEt),2] and (Et4N)4[ Re,Fe,S,(SEt),,] containing [ReFe,(p,-S),] cubane-type units have 70 D. J. Evans A. Hills D. L. Hughes G. J. Leigh A. Houlton and J. Silver J. Chem. Soc. Dalton Trans. 1990 2735. 71 T. D. P. Stack J. A. Weigel and R. H. Holm Znorg. Chem. 1990 29 3745. 72 J. A. Weigel K. K. P. Srivastava E. P. Day E. Munck and R. H. Holm J. Am. Chem. Soc. 1990 112 8015. 73 P. R. Challen S-M. Koo C. G. Kim W. R. Dunham and D. Coucouvanis J. Am. Chem. Soc. 1990 112 8606. 74 Q. Lin L. Huang H. Liu X. Lei D. Wu B. Kang and J.Lu Znorg. Chem. 1990 29 4131. E J. Berry been isolated in 66-84% yields from systems containing (Et,N)[ ReS,] FeCl, and NaSEt in methanol.75 The cluster structure of [Re2Fe6S,( SEt),] was shown to consist of two terminal cubane-type ReFe,S,( SEt) subclusters which are bridged through the rhenium atom by three p2-SEt sulphur atoms or as in (Et4N)2[Re2Fe7S8(SEt),2] and (Et,N),[Re2Fe,s8(sEt),,] by a trigonal (p2-SEt),Fe(p2-SEt) unit (Figure 7). S(5') Figure 7 Structure of the cluster [Re,Fe2S,(SEt),,l4-(Reproducedby permission from Znorg. Chem. 1990 29 3493) Comparisons of properties were made with the previously reported molybdenum- and tungsten-clusters of the type [M2Fe6S8(SR)9]3- and [M2Fe7S8(SR)12]3-34- with similar structures.Cubane-type clusters of composition NiFe,Q (Q = S,Se) have been prepared by reductive rearrangment of linear [Fe,Q,( SEt),13- species.76 A new iron-sulphur compound Fe6S,( p-SPh)( P-Bu,"),(SPh) has been ~ynthesized~~ by the reaction of Fe(P-Bu,"),(SPh) and (Bu,"N),[Fe,S,(SPh),] in MeCN/THF. The core was found to consist of six Fe2S2 units fused in the form of a basket by the sharing of edges (Figure 8). The mechanism of the reaction of cuboidal [MO,F~S~(H~O),,]~+ with dioxygen has been studied in The solution chemistry of the cuboidal mixed metal complex has also been examined.79 The reactions of the complexes [FeL,X,][FeX,] (L = OPPh or OAsPh,; X = C1 or Br) with sulphur dioxide have been shown" to give some rare examples of iron( 111) complexes of sulphur dioxide of composition [FeL,{OS(O)X},[ FeX,].The isolation of the sulphuric acid derivatives (PPh30)-(PPh,OH)(HSO,) and (AsPh,OH)(HSO,) was also described. Structural aspects of the a transition in stoichiometric iron sulphide FeS have been described and a high temperature phase identified.,' Similar studies of the a transition in off-stoichiometric Fe,-,S crystals were subsequently reported.82 75 S. Ciurli M. Carrie and R. H. Holm Inorg. Chem. 1990 29 3493. 76 S. Ciurli S.-B. Yu R. H. Holm K. K. P. Srivastava and E. Munck J. Am. Chem. Soc. 1990 112 8169. 77 C. Chen J. Cai Q. Liu D. Wu X. Lei K. Zhao B. Kang and J. Lu Inorg. Chem. 1990 29 4878. 78 P. W. Dimmock and A. G. Sykes J. Chem. Soc. Dalton Trans. 1990 3101. 79 D. W.Dimmock D. P. E. Dickson and A. G. Sykes Inorg. Chem. 1990 29 5120. 80 B. Beagley D. G. Kelly P. P. MacRory;C. A. McAuliffe and R. G. Pritchard J. Chem. SOC.,Dalton Trans. 1990 2657. 81 F. Keller-Besrest and G. Collin J. Solid State Chem. 1990 84 194. 82 F. Keller-Besrest and G. Collin J. Solid State Chem.. 1990. 84 211. 0,S Se Te Figure 8 Structure of Fe,S,(p-SPh)( P-Bu,"),(SPh) (Reproduced by permission from Znorg. Chem. 1990 29 4878) Multiple scattering (MS)-Xa methods have been used to calculate the electronic structure of several clusters which contain an octahedral cogs6 core.83 The syntheses and structural determination of IrSe and IrS2 has been repeatedg4 and new structural data described. Iridium thioether chemistry has also attracted attention and the synthesis and structures of [IrL2][PF6I3 and [IrHL,][PF,] (L = 1,4,7-trithiacycIononane)have been reported.85 A series of novel nickel compounds with multidentate thioether thiolate ligands including nitrogen and oxygen donors in S6,S5,0S4,NS4,and S4 donor sets have been synthesized and characterized by spectroscopic methods and X-ray structure analyses.86 The synthesis spectroscopy and electrochemistry of heterocyclic thionato complexes of divalent nickel has been de~cribed.~' The complexes [Ni3Y2(PEt3)J2+ (Y = S or Se) have been foundg8 to 83 G.G. Hoffman J. K. Bashkin and M. Karplus J. Am. Chem. Soc. 1990 112 8705. 84 S. Jobic P. Deniard R. Brec J. Rouxel M. G. B. Drew and W. I. F. David J. Solid State Chem. 1990 89 315.85 A. J. Blake R. 0. Could A. J. Holder T. I. Hyde G. Reid and M. Schroder J. Chem. SOC.,Dalton Trans. 1990 1759. 86 D. Sellmann S. Funfgelder G. Pohlmann F. Knoch and M. Moll. Inorg. Chem. 1990 29 4772. 87 E. S. Raper A. M. Britton and W. Clegg J. Chem. SOC.,Dalton Trans. 1090 3341. 88 F. Lecconi C. A. Ghilardi S. Midollini A. Orlandini A. Vacca and J. A. Ramirez J. Chem. SOC. Dalton Trans. 1990 773. F. J. Berry undergo metathetical reactions with halides and pseudohalides to give both asym- metric monosubstituted [Ni,Y,( PEt,),X]+ and disubstituted [Ni,Y2( PEtJ4X2] derivatives.88 Nickel( III)-sulphur bonding has also been the subject of study during an investigation of tris(xanthate) compounds of trivalent nickel.89 A large family of new quarternary rhenium chalcohalides M+[Re6Y5X9]- (M = alkali metals Cu Ag; Y = S Se; X = C1 Br) has been synthesized by high- temperature reactions and shown to adopt isotypic ~tructures.~~ The crystal structure of KRe,SeSC19 was shown to consist of discrete [Re6Y5X9]- and K+ ions in a rock-salt type structure.An unusual feature is the random distribution of two-types of anions on the eight positions of the first coordination shell surrounding the metallic clusters (Figure 9). It is also interesting to note from the view of the 001 basal plane that the K+ ions occupy a nearly perfect octahedral site formed by six apical chlorine atoms each of which belongs to one of the six neighbouring units. The solubility of these compounds in organic solvents suggests an important future for these materials in further synthesis.d Figure 9 The crystal structure of KRe,Se,Cl shown in the basal plane (full circles Re open circles (Se-Cl); hatched circle C1) (Reproduced by permission from Mat. Res. Bull. 1990 25 1227) The oxidative addition of thiols to binuclear platinum complexes has been described.” The substitution chemistry of the triangulo-platinum clusters [Pt3(p-Co)3-,(p-S02),{P(C6Hll)3}3] (n = 0-3) with carbon monoxide and sulphur dioxide ligands has been described and some mechanistic implications discussed.92 Dimethyl sulphoxide has been shown to substitute one pyridine or substituted pyridine (Xpy = pyridine 4-methylpyridine 3,5-dimethylpyridine 4-chloropyridine or 4-cyanopyridine) from cis-[Pt(Xpy),I,] to form trans-[Pt(Xpy)-(dmso)I,] complexes.93 Infrared- and NMR spectral evidence for the binding of 89 S.B. Choudhury D. Ray and A. Chakravorty Inorg. Chem. 1990 29 4603. 90 A. Perrin L. Leduc M. Potel and M. Sergent Mat. Res. Bull. 1990 25 1227. 91 N. Hadj-Bagheri R. J. Puddephatt L. Manojlovic-Muir and A. Stefanovic J. Chem. Soc. Dalton Trans. 1990 535. 92 S. G.Bott A. D. Burrows 0.J. Ezomo M. F. Hallam J. G. Jeffrey and D. M. P. Mingos J. Chem. SOC.,Dalton Trans. 1990 3335. 93 T. T. B. Ha F. L. Wimmer J.-P. Souchard N. P. Johnson and J. Jaud J. Chem. SOC.,Dalron Trans. 1990. 1251. 0,S Se Te the dmso ligand through sulphur was presented and the trans structure confirmed by X-ray crystallography.Several platinum metal complexes of mixed thia/oxa ionophores have been reported.94 The synthesis and spectroscopic properties of copper compounds with the tri- dentate ligand 1,3-bis (5-methyl-4-imidazolyI)-2-thiapropane have been described.95 The first X-ray structure determinations of crystalline materials isolated from the addition of phenyllithium to cuprous bromide in neat dimethyl sulphide solution have been reported.96 The structural properties of dimethyl sulphide solvates of phenylcopper and lower and higher order lithium phenylcuprate reagents were also described. The complex [NEt,],[ Mo2Cu5S602( Me,NCS,),] has been prepared by the re- action of CuCl Na[S2CNMe2] NEt,Br and [NH4I2[MoS2O2] in dimethylfor- mamide s~lution.~’ The Mo2Cu5S602 framework in the anion was found to consist of two defective cubane-like units OMoS3Cu2 and OMoS3Cu3 linked through two weak Cu-S bonds and bridged by two Me,NCS ligands (Figure 10).The synthesis of the compounds [NEt,],[ M2Cu,S,( Me2NCS2)J [PPh,],[ M2Cu5S6O2(EtzNCs2),] 13‘) Figure 10 Perspective view of the anion [Mo,Cu,S,O,( Me,NCS,),]’-(Reproduced by permission from J. Chem. Soc. Dalton Trans. 1990 1023) 94. A. J. Blake G. Reid and M. Schroder J. Chem. Soc. Dalton Trans. 1990 3849. 95 A. C. van Steenbergen E. Bouwman R. A. G. de Graff W. L. Driessen J. Reedijk and P. Zanello J. Chem. Soc. Dalton Trans. 1990 3175. 96 M. M. Olmstead and P. P. Power J. Am. Chem. SOC. 1990 112 8008. 97 H. Liu R. Cao X. Lei D. Wu G. Wei Z. Huang M.Hong and B. Kang J. Chem. SOC.,Dalton Trans. 1990 1023. 60 F. J. Berry (M = Mo or W) and [NEt4]2[MoCu3S4(Et2NCS2)3]was also reported. Further evidence of sustained interest in systems related to blue copper proteins is illustrated by the reported98 synthesis and characterization of copper( 11) enethiolate complexes derived from (IR)-3-hydroxymethylene bornane-2-thione and 2-aminothia-alkyl- 1 -methylbenzimidazoles (donor set N2SS*) or diamines (donor sets N2S2). Coordina- tion compounds of the new ligand 1,8-bis(3,5-dimethyl-2-pyrazolyl)-3,6-dithiaoc-tane with MC1 (M = Fe Mn Ni Co Zn Cu or Cd) MBr (M = Mn Co Ni or Zn) Cu(BF,), and CuX (X = BF, NCS C1 Br or I) have been described.99 The crystal structure of B~CU~.&~ has shown"' the solid to be derived from five sets of CuS4 tetrahedra one CuS trigonal pyramid and one CuS3 trigonal plane.The edge sharing of two sets of CuS4 tetrahedra gives rise to a three- dimensional network and the material was found to exhibit metallic conductivity. Phases in the PbS-rich region in the Ag2S-PbS-Bi2S3 system have been studied by high resolution transmission electron microscopy. ''' Samples quenched from the melt or melted and annealed at 773 or 973 K were found to contain a number of new chemically twinned phases composed of galena-like slabs four- five- seven- and eight-octahedra wide and joined along twin planes. Whilst ordered phases were found to predominate in the PbS-rich region of the phase diagram both ordered and disordered intergrowths were found in the PbS-poor region.The role of silver in stabilizing slabs of galena-like material five- and eight-octahedra wide and its function in the formation of these twinned phases was discussed. The glass forming region in the AgPO3-Ag,S-AgI system has been determined and some physical chemical properties investigated.'' The results showed that the conduction is essentially ionic in nature and due to silver ions. Electroluminescent polycrystalline ZnS :Mn :Cu Dy(C1) phosphors with different concentrations of Cu+ and fixed concentrations of Mn2+ and Dy3+ have been prepared." The p to (Y phase transformation was found to be inhibited by copper addition and the results associated with the dopant-induced creation of zinc vacancies and subsequent atomic rearrangements.Total energy calculations have been performed for 17 atom ( M~S(S~),ZII,,-~M~,) and 29-atom (MnS(Se),Zn,,-,- Mn,S(Se),,) clusters representing the first second and third neighbours of a central Mn2+ ion in ZnMnS and ZnMnSe lattice^."^ The results showed an energy gain for the Mn clustering as compared with the random impurity distribution. Samples of cobalt-doped ZnS ZnSe CdS and CdSe have been prepared by the direct combination of elements and the limit of cobalt solubility determined."' The antiferromagnetic interactions of cobalt in the zinc-systems was found to be greater than that observed in the cadmium chalcogenides. Some similar observations were 98 L. Casella M. Gullotte E. Suardi M. Sisti R. Pagliarin and P. Zenello J.Chem. Soc. Dalton Trans. 1990 2843. 99 W. G. Haanstra W. A. J. W. van der Donk W. L. Driessen J. Reedijk J. S. Wood and M. G. B. Drew J. Chem. Soc. Dalton Trans. 1990 3123. I00 J. S. Chang H. Y.-P. Hong G. H. Lee and Y. Wang Mat. Res. Bull. 1990 25 863. 101 A. Skowron and R. J. D. Tilley J. Solid State Chem. 1990 85 235. 102 J. M. Reau L. Jun B. Tanguy J. J. Videau J. Portier and P. Hagenmuller J. Solid State Chem. 1990 85 228. 103 P. R. Bote P. K. Patil J. K. Nandagawe and R. D. Lawanger-Pawar Mat. Rex Bull. 1990 25 1257. I04 K. K. Stavrev S. I. Ivanov K. D. Kynev and G. St. Nikolov J. Solid State Chem. 1990 86 136. 105 C.-M. Niu R. Kershaw. K. Dwight. and A. Wold J. Solid State Chem. 1990 85 262. 0 S Se Te 61 made during subsequent studies of iron-doped zinc- and cadmium-chalcogenides.lo6 The incorporation of Zn2+ impurity within calcium sulphide phosphors has been found'" by thermo- and electrothermo-luminescence studies to effect the general features of the glow curves which may be interpreted in terms of thermal and filled excitation of filled traps.Solid solutions of general formulation (NH,),Cd,( S04)x(Se04)3-x K2Mn,(S04)x(Se04)3-x T12Cd2(S04),(Se04)3-,(3 2 x 3 2.75) and (NH4)2Mn2- (S04),(Se04)3-,(3 2 x 2 2.50) have been prepared and used to study the phase transition mechanism for the langbeinites."' Low temperature magnetization measurements have been reported'" for com- pounds of the type EU~~~+EU,- 3+ Lil-,S2 and in some materials have been inter- preted in terms of ferromagnetic cluster formation.Solid solution regions in the pseudo ternary system Yb,S3-YbS-MnS have been structurally characterized.' lo An electron diffraction study of various ytterbium sulphide preparations has confirmed"' the existence of two orthorhombic forms of Yb3S4. Current interests in the ionic conductivity and infrared transmissions of compounds of the type ALnS2(A = Li Na K Ln = Y rare earth element) have continued. This is well illustrated by the reported preparation of LiYS with the hexagonal a-NaFeO structure from isostructural NaYS by ion-exchange in a molten LiCl/KCl mixture at a relatively low temperature.' l2 4 Selenium A decaselenadecalin anion Slo2- has been prepared in over 70% yield by heating a solution of polyselenide in dimethylformamide in the presence of [Ph3PNPPh3]C1 and a trace of iodine.'13 The product was isolated as black crystals corresponding to a [Ph3PNPPh3]+ salt.The two bridgehead selenium atoms in this bicyclo[4.4.0] system (Figure 11) were coordinated to give a distorted pseudo-trigonal bi-pyrammidal geometry. It has been known for a long time that iodine significantly influences the rate of crystallization of elemental selenium. It is therefore interesting to note the use of multinuclear NMR spectroscopy to reveal dissmutation equilibria in a model solution of diselenide with iodine and the intercalation of iodine molecules between the chains of elemental selenium from a loose charge-transfer adduct of the same diselenide with iodine in the solid state.114 A stereochemical study of a-lithio Felenides has been reported during an investiga- tion of lithium-selenium exchange.' l5 The insertion of lithium ions within TlInSe chains has been accomplished by electrochemical techniques in non aqueous gal- 106 J.Dicarlo M. Albert K. Dwight and A. Wold J. Solid Stare Chem. 1990 87 443. 107 P. K. Patil and R. D. Lawangar-Pawar Mar. Rex Bull. 1990 25 25. 1ox M. L. M. Sarrion A. R. Clemente and L. M. Vila J. Solid Srare Chem. 1990 84 308. 109 M. Wintenberger and M. Palazzi Mat. Res. Bull. 1990 25 365. I10 M. Guittard A. Chilourt M. F. Gardette M. Wintenberger and A. Tomas Mat. Rex Bull. 1990,25,1291. 'IL L. C. Ottero-Diaz A. R. Landa-Canovas and B. G. Hyde J. Solid State Chem.1990 89 237. 112 D. 0. Kipp and T. A. Vanderah Mat. Rex Bull. 1990 25 933. 113 D. Fenske G. Krauter and K. Dehnicke Angew. Chem. Int. Ed. Engl. 1990 29 390. I14 W. W. Du Mont A. Martens S. Pohl and W. Saak Inorg. Chem. 1990 29 4847. 11s H. J. Reich and M. D. Bowe J. Am. Chem. SOC.,1990 112 8994. F. J. Berry Se(2') fp Figure 11 Mo1ecu:ar structure of the S ion (Reproduced by permission from Angew. Chem. Int. Ed. Engl. 1990 29 390) vanic cells.' l6 The electrochemical properties during the first discharge were studied and the optical properties of the pure and lithium-inserted samples were examined by FTIR spectroscopy. Given the large number of sulphur-nitrogen compounds that are now known it is interesting that few selenium-nitrogen compounds have been structurally charac- terized.This in part reflects the lack of suitable stable precursors that can be prepared in satisfactory yields. It is therefore interesting to note the rep~rted''~ synthesis in good yield of the new compound Se[N(SiMe,),],. The X-ray crystal structure determination showed the solid to consist of isolated molecules containing V-shaped SeN2 units (Figure 12). Figure 12 Molecular structure of Se[N(SiMe,)2]2 (Reproduced by permission from Znorg. Chem. 1990 29 5140) Single crystals of germanium selenide GeSe have been grown by chemical vapour transport techniques structurally characterized by X-ray diffraction and examined for electrical and photoelectrochemical activity.' '' A novel approach to the synthesis of ring systems containing phosphorus nitrogen and sulphur or selenium has been mentioned earlier.23 The use of NMR spectroscopy 'I6 I.Samaras K. Kambas and C. Julien Mat. Rex Bull. 1990 25 1. M. Bjorgvinsson H. W. Roesky F. Pauer D. Stalke and G. M. Sheldrick Inorg. Chem. 1990,29 5140. N. Le Nagard C. Levy-Clement A. Katty and R. M. A. Leith Mat. Res. Bull. 1990 25 495. 0 S Se Te and X-ray crystallography to characterize compounds of general composition R3PE-A1Cl3(R= Ph or NMe, E = S or Se) has also beeen discussed.26 The growing importance of non-oxide chalcogenide glasses in infrared optics and semiconductor technology is reflected by the development of 31P-77Se spin echo double resonance NMR techniques for the structural characterization of such materials."' Compounds of the type M2X3(M= Sb Bi X = Se Te) have been doped with germanium tin or lead and found to contain one-dimensional superstructures which are amenable to characterization by electron microscopy.120 The materials were described in terms of superstructures built up of sequences of five- and seven-layer lamellae. The compound Se214(AsF,),.S02 has been preparedl2l quantitatively by reacting stoichiometric amounts of selenium iodine and arsenic pentafluoride. The com- pound Se214(Sb2F11)2 was also synthesized from the reaction of selenium and 12Sb2Fl in liquid sulphur dioxide. The 77Se NMRspectra recorded from the two compounds in sulphur dioxide at -70°C indicated the presence of Se;+ and Se13+. X-Ray crystallography showed the crystal packing of Se214(ASF6),.2sO and Se,I,( Sb2F11) to consist of columns of Se212+ ASF,- and SO2and columns of Se,I;+ and Sb2Fl respectively (Figures 13 and 14).The Se214,+ cations in both salts were found to be Figure 13 Crystal packing of Se214(Sb2F,1)2 (Reproducedby permisssion from Inorg. Chem. 1990 29 3529) similar and to adopt the eclipsed configuration with long Se-Se bonds (average 2.841(6)A) (Figures 15 and 16). The significant intraionic interactions between the syn iodine atoms (average 3.673 (4)A) were associated with the distorted trigonal prismatic shape of the cation. The shorter Se-I bonds (average 2.451(5)A) than those observed in SeI,+ (average 2.5 10(2)81) were attributed to 4p.rr-5~7~ bonding with a formal bond order of 1.25 per Se-I bond.The Se2142+ species was envisaged as containing two SeI," radical cations joined by a 6-centre 2 electron T*-T* bond. The results were related to the similar geometries found in the Ses2+ SS2+ and S204,-ions (Figure 16). 119 D. Lathrop and H. Eckert J. Am. Chem. SOC.,1990 112 9017. 120 N. Frangis S. Kuypers C. Manolikas G. Van Tendeloo J. Van Landuyt and S. Amelinckx J. Solid State Chem. 1990 84 314. I21 W. A. S. Nandana J. Passmore P. S. White and C.-M. Wong Inorg. Chem. 1990 29 3529. F. J. Berry C Figure 14 Crystal packing of Se2I2(AsF6),.SO (Reproduced by permission from Inorg. Chem. 1990 29 3529) Figure 15 The se2142+cation in Se2I4(ASF6)2.S02 (Reproduced by permission from Inorg.Chem. 1990 29 3529) Se(1) Se(2) Figure 16 Structure of the Se2142+cation in Se,I4(Sb2Fl1) and the corresponding Se6 atoms in the Ses2+cation in Se8(A1Cl4),in which the two Se3+fragments are represented by shaded thermal ellipsoids (Reproduced by permission from Inorg. Chem. 1990 29 3529) 0,S Se Te A series of three manganese polyselenide anions derived from the reaction of Mn2(CO)lo and polyselenide anions in DMF solution have been isolatfd and characterized.'22 The reaction of Mn2(CO),o with 1 equivalent of K2Se3 in DMF was found to generate [Mn2(Se2)2(C0)6]2-. The reaction of Mn2(CO)lo with 2 equivalents of K2Se produced [Mn2( Se4)2(CO)6]2- which was also obtained from the reaction of [Mn2(Se2)2(C0)6]2- with red selenium. The thermolysis of [Mn2(Se4)2(C0)6]2- in DMF was found to give [Mn(Se,),I2- as the final product of oxidative decarbonylation.All three products were structurally characterized as their [(C6H5)4P]+ salts. Both the carbonyl-containing anions [Mn,( Se2)2( cO),l2-and [Mn2(Se4),(CO),l2- (Figures 17 and 18) were found to consist of two manganese tricarbonyl fragments chelated by a Sen2- chain (n = 2,4). One of the terminal selenium atoms on each manganese also bridges to the second metal centre thereby completing its 18 electron count. Thus each metal centre can be viewed as being Figure 17 The anionic fragment [Mn,( Se,),( C0),l2-(Reproduced by permission from Inorg. Chem. 1990 29 3134) Figure 18 The [Mnz(Se,)2(CO),]2-dimer (Reproduced by permission from Inorg. Chem.1990 29 3134) S. C. O'Neal W. T. Pennington and J. W. Kolis Inorg. Chern. 1990 29 3134. F. J. Berry pseudooctahedrally coordinated by three selenium atoms and three carbonyl ligands. The monomer [Mn(Se,),I2- was found to contain two Se;- chains chelating to a manganese (11) centre in a tetrahedral fashion (Figure 19). Single crystals of cu-Mol5Sel9 have been prepared by the deintercalation of In3MoI5Sel9 with iodine.'23 The binary molybdenum selenide was found to contain Mo,Se and Mo,Se, clusters (Figure 20). Se(17) Figure 19 An enantiomer of [Mn(SeJ2I2-(Reproduced by permission from Inorg. Chem. 1990,29,3134) Figure 20 The Mo6Se8 and Mo,Se, clusters in a-Mo,,Se, (Reproduced by permission from J. Solid State Chem. 1990 85 332) B.D. Davis and W. R. Robinson J. Solid State Chem. 1990 85 332. 0,S Se Te The reaction of WC14(Me2S)2 with Me,SiSePh in CH2C12 solution followed by addition of PPh4Cl has been shown'24 to give a mixture of the two isostructural compounds [PPh4I2[Cl3W(p-Se)( p-SePh),WCl3]-2CH,CI and its mixed oxidation state analogue [PPh4]2[C13W(p-CI)(p-SePh)2WC13]-2CH2C12. The anion [Cl,W(p- SePh),( p-Se) WC1,I2- was found by X-ray crystallography to be confacial biocta- hedral with three selenium atoms in the bridging position (Figure 21). 77Se NMR showed the structure to be retained in solution. Figure 21 Structure of the [Cl,W(p-SePh),( pSe)WCl,]'- anion (Reproduced by permission from Znorg. Chem. 1990 29 3290) The synthesis of NiFe,Se4 cubane-type clusters by the reductive rearrangement of the linear [Fe,Se,(SEt),l3- species has been mentioned earlier in this rep01-t.~~ The phase diagram of the binary CrSe and FeSe systems (1.0 L x d 1.4) has been determined by X-ray- and DTA-meas~rements.'~~ The first example of a diselenoether complex of Co3+,[Co( MeSeCH2CH,SeMe),X2]BPh4 (X = C1 Br or I) has been prepared and characterized by UV-visible and multinuclear NMR spectroscopy.'26 124 J.M. Ball P. M. Boorman J. F. Fait H.-B. Kraatz J. F. Richardson D. Collison and F. E. Mabbs Znorg. Chern. 1990 29 3290. 125 S. Katsuyama Y. Ueda and K. Kosuge Mat. Res. Bull. 1990 25 913. 126 J. L. Brown T. Kemmitt and W. Levason J. Chem. SOC.,Dalton Trans. 1990 1513. 68 F. J. Berry The identification of v2 and 77,(Se)-p2 selenophene( SeI) coordination in Cp*(C0),Re(2,3-v2-SeI) and Cp*(CO),Re( ~2(Se)-p2-SeI)[W(CO)4 (PPh,)] has been re~0rted.l~~ The preparation and characterization of compounds of composition [R(SeSNd(PR3),] [Pt(Se2N2)(pR3)2l3 [R(sesN,H)(PR,),]BF4 and [R(Se,N,H)- (PR3),]BF4 has been described.'28 The M(Se4),,- anions (M = Ni Pd Pt Zn Cd Hg and Mn) have been synthe- sized and characterized.129 The investigation of phases in the CuGe2P3-Cu2GeS3 system has been mentioned earlier.39 The metathetical reaction of the [Ni,Y,( PEt3)6I2+ complex with halides and pseuodhalides to give both asymmetric monosubstituted [Ni,Se,( PEt,),X]+ and disubstituted [Ni3Se,( PEt,),X,] derivatives has also been described.88 The synthesis of the [Cu(C3Se5),I2- and [Ni(C,Se5),l2- anion complexes and the characterization of their spectroscopic and electrical properties has been reported.130 The structure of copper-deficient T1Cu,Se3 has been to be similar to that adopted by other thalium copper chalcogenides such as TlCu,Se and TlCu,Se,. The phases which can exist in the Cu2Se-Bi2Se system have been investigated.', The theoretical study of Mn2+ clustering in Zn,-,Mn,S and Zn,-,Mn,Se has been mentioned previou~ly.'~~ The preparation and properties of cobalt- and iron- doped ZnSe and CdSe have been described. 105,106 The growth and characterization of single crystals of composition Zn,-,Mn,Se(O < x < 0.53) and Zn,-,Fe,Se (0.01 < x < 0.22) has been re~0rted.l~~ Polycrystalline samples of the semimagnetic semiconductors of composition Cdl -,Fe,Se have been structurally characterized by X-ray diffraction technique^.',^ The salts [PPh4I2[ZnC3Se5),] and [PPh,],[Zn( CSe,),] have been prepared and structurally ~haracterized.'~' The compound (NH,),Cd,(SeO4),.3H20 has been synthesized and shown to contain two types of tetrahedrally coordinated selenium atoms which form double chains to give a three dimensional str~cture.'~~ The formation of solid solutions and the characterization of phase transitions in langbeinites of composition M21M211(Se04)3(M1 = NH, K T1) (M" = Cd Mn) has been mentioned earlier.'08 The phase diagram of the La,O,Se-Ga,Sej?ystem has been investigated by X-ray diffra~ti0n.l~~ and DTA showed the two phases of composition (LaO)4Gal,88Se4,89 (LaO)GaSe to undergo phase transformations at high temperatures.5 Tellurium The capacity of the elements sulphur selenium and tellurium to form homo- and hetero-nuclear polycations is well known. Of the tellurium-containing cations Te4,+ and Te2- as well as [Te2Se2]+ [Te3SeI2+ [Te2Se4I2+ [Te3S3I2+ [Te2Se6I2+ and 12' M.-G. Choi and R. J. Angelici J. Am. Chem. Soc. 1990 112 7811. I. P. Parkin and J. D. Woolins J. Chem. Soc. Dalton Trans. 1990 925. lZ9 M. A. Ansari C. H. Mahler G. S. Chorghade Y.-J. Lu and J. A. Ibers Inorg. Chem. 1990 29 3832. 130 G. Matsubayashi and A. Yokozawa J. Chem. SOC.,Dalton Trans. 1990 3013. R. Berger L. Eriksson and A. Meerschaut J. Solid State Chem. 1990 87 283. 132 J. C. Garcia G. Brun B. Liantard J.C. Tedenac and M. Maurin Mat. Res. Bull. 1990 25 241. I33 M. Pemianiuk Mat. Res. Bull. 1990 25 337. 134 E. Dynowska A. Sarem B. Orlowski and A. Mycielski Mat. Res. Bull. 1990 25 1109. 13' G.Matsubayashi K.Akiba and Y. Tanaka J. Chem. SOC.,Dalton Trans. 1990 115. 136 M. L. Martinez A. Rodriguez L. Mestres X. Solans and E. H. Bocanegro J. Solid State Chem. 1990 89 88. 137 M. P. Pardo S. Benazeth M. Guittard and C. Ecrepont Mat. Res. Bull.. 1990 25 1043. 0 S Se Te [Te2Se8I2+ have so far been structurally characterized. It is therefore interesting to note the formation'38 of the new Teg2+ polycation which is analogous to the known homonuclear cations of sulphur and selenium s8*+and Se82+. The cation was found in the new compound Te8[WCl6I2 which was synthesized by the oxidation of tellurium with TeCl .The structure determination showed the compound to contain Teg2+ cations and [wc16]- anions. The Tes2+ ion adopts a bicyclic framework composed of two five-membered rings in envelope conformation (Figure 22). The bicyclic cation was found to be associated to give chains and amenable to description as a tellurium polycation [Ten]n/4+ (Figure 23). Figure 22 Structure of Teg2+ion in TeJ WC~,] (Reproduced by permission from Angew. Chem. Int. Ed. Engl. 1990 29,293) Figure 23 Association of Te;+ cations to form the tellurium polycation [Te,] n'4+ (Reproduced by permission from Angew. Chem. Znt. Ed. Engl. 1990 29,293) Given that the only known property of tellurium nitrides is their highly explosive character it is interesting to record the ~ynthesis'~~ of the stable tellurium nitride of composition (ClTeNSN),N which decomposes at 207 "C.The compound which is therefore the first tellurium nitride that is stable at room temperature was formed from the reaction of tellurium tetrachloride and Me,SiN=S=NSiMe in toluene and was crystallized from dimethylformamide. X-ray crystallography showed three solvent dimethylformamide molecules to be coordinated via their oxygen atoms to the tellurium atoms of (CITeNSN),N (Figure 24). The three tellurium atoms form a puckered twelve-membered ring with the three bridging NSN ligands and a six membered ring with the three bridging chlorine atoms. In the plan view (Figure 24 top) the three tellurium atoms can be seen to be bridged by a further nitrogen atom N( 1).The side view (Figure 24 bottom) shows the trigonal-pyramidal arrangement of the Te,N(l) unit. The Te'" atoms in (ClTeNSN),Nv3DMF adopt a distorted octahedral environment. J. Beck Angew. Chern. In(. Ed. Engl. 1990 29 293. I39 H. W. Roesky J. Munzenberg and M. Noltemeyer Angew. Chem. fnt. Ed. Engi. 1990 29 61. F. J. Berry Figure 24 Crystal structure of (CITeNSN),N.3DMF. Above top view. Below side view of molecule without dimethyljormamide molecules (Reproduced by permission from Angew Chem. Znt. Ed. Engl. 1990 29 61) The synthesis crystal structure and characterization of two dinuclear rhodatel- luraboranes [{(PPh3)2RhTeB,oH,0}2] and [(PPh3)(CO)Rh2Te2B20H20] has been de~cribed.'~' The thallium-tellurium system has been reinvestigated by thermal analysis and X-ray diffra~tion.'~~ The compound of composition TlTe was found to contain a chain-type structure [Te] (with short Te-Te atomic distances of 3.026 and 3.085 A) connected by the T1' polyhedral coordination.The Tl,Te3 structure was found to be built from TlTe6 layers perpendicular to the c-axis and consistent with the simultaneous presence of T1' and Tl"' in a compound of formulation T1'T1'''Te6. The crystal structure of the compound Tl,GeTe has been described'42 in terms of layers parallel to the [OOl] plane and to contain [Ge2Te6I4- anions and Te clusters. The compound Te[N(SiMe,),] has been prepared"' and shown to consist of isolated Te[ N(SiMe3)2]2 molecules with intermolecular Te.-Te distances of 377 pm (Figure 25). 140 G. Ferguson A. J. Lough X. X. Faridoon M. N. McGrath T. R. Spalding J. D. Kennedy and X. L. R. Fontaine J. Chem. SOC.,Dalton Trans. 1990 1831. 141 A. A. Toure G. Kra R. Eholie J. Olivier-Fourcade and J.-C. Jumas J. Sulid Srare Chem. 1990,87 229. 142 A. A. Toure G. Kra R. Eholie J. Olivier-Fourcade J.-C. Jumas and A.Maurin J. Solid State Chem. 1990 84 245. 0,S Se Te LJ Figure 25 Molecular structure of Te[ N(SiMe,),] (Reproduced by permission from Inorg. Chem. 1990 29 5140) The characterization by electron microscopy of continuous series of one-dimensional structures in compounds based on M2X,(M = Sb Bi X = Se Te) has been noted earlier.12' The compound XeF has been to react with cis-(HO),TeF to give a yellow insoluble polymer (XeO,TeF,) which is stable to about 80 "C.The reaction of cis-(HO),TeF with Xe2F3+AsF6- was found to give a material of composition FeXe-OTeF,-O-Xe+AsF,-which when recrystallized in anhydrous HF gave a crystalline solid HF-HO-TeF,-O-Xe+AsF,-.The stabilization of the chain structure in the newly synthesized compound Ta,Te,Si has been associated with both the strong metal-metal and Ta-Si bond-ing.14 Band structure calculations suggested that the compound is a metallic conduc- tor in which the states contributing to the conduction bands are derived from the Ta 5d orbitals. The structure of Ta,Te,Si was shown'45 to be a new structure type and to represent a new class of compounds.The structure was found to be based on square Ta monomers stacked antiprismatically to form an infinite one-dimensional metal atom network. The location of a silicon atom in the centre of each tantalum square antiprism gives rise to the formation of an infinite silicon chain inside the tantalum chain. The bridging by tellurium atoms to each side of the tantalum square leads to the formula Ta,Te,Si. The individual Ta,Te,Si chains are held together by weak Te-Te van der Waals interactions and pack in an orthorhombic unit cell (Figure 26). A side view which clearly illustrates the 10-fold coordination (eight tantalum atoms and two silicon atoms) of silicon and the four-fold coordination of tellurium is shown in Figure 27. MoTe layers have been synthesized by annealing a molybdenum foil under tellurium pressure.'46 The films were found to be stoichiometric and to crystallize 143 L.Turowsky and K. Seppelt Inorg. Chem. 1990 29 3226. 144 J. Li R. Hoffman M. E. Badding and F. J. DiSalvo Inorg. Chem. 1990 29 3943. 145 M. E. Badding and F. J. DiSalvo Inorg. Chem. 1990 29 3952. 146 J. C. Bernede J. Pouzet M. Manai and A. Ben Mouais Mat. Res. Bull. 1990 25 31. F. J. Berry Figure 26 View of the Ta,Te,Si structure parallel to the orthorhombic c-axis. The silicon atoms are indicated by partially hatched circles tantalum atoms by dotted circles and tellurium atoms by open circles (Reproduced by permission from Znorg. Chem. 1990 29 3952) Figure 27 Side view of one repeat unit in the Ta,Te,Si chain (Reproduced by permission from Inorg.Chem. 1990 29 3952) in the hexagonal structure. The c-axis orientation was shown to be essentially perpendicular to the plane of the molybdenum substrate. The reaction of W(CO)6 with pure [(C6H,)&[Te,] has been shown'47 to generate a new 14-membered cluster of composition [(W(C0)3)6(Te2),]2-. The structure of the cluster (Figure 28) is unusual and may be the first in a large class of new transition-metal main-group cages. The synthesis and characterization of the first examples of ditelluroether complexes of cobalt(HI) has been mentioned earlier.'26 The tellurium-centred cubic cluster L. C. Roof W. T.Pennington and J. W. Kolis J. Am. Chem. Soc. 1990 112 8172. 73 0,S Se Te Figure 28 Structure of the cluster [W(CO),),(Te,),]2-(Reproduced by permission from J.Am. Chem. Soc. 1990 112 8172) Ni,Te( P~-T~)~( L)8 has on the basis of extended Huckel molecular orbital calcula- tions for the cluster and its experimentally known-centred analogue Ni9( p4-Te),(PEt3) ,been described as a stable The calculations showed that the interstitial nickel or tellurium atom binds to the empty cluster at the expense of Ni-Ni and Ni-Te bonding within the cluster framework. The interstitial nickel atom compensates by bonding weakly to the framework nickels primarily through its a,,(4s) orbital; the central tellurium atom bonds strongly to both the nickel cube and the face-capping tellurium atoms. Large HOMO-LUMO gaps suggest that 130 or 114 electrons are optimum for Ni8Te( L),.The synthesis and characterization of two new tellurium-containing clusters of composition Fe,Ru(CO),(p,-Te) and Fe2Ru2(CO)ll(p4Te)2 has been re~0rted.l~~ The synthesis and structural characterization of the new clusters of composition RU4(C0)11(p4-Te)2 Ru3(CO)6(PPh3)3(p.,-Te)2 3 and Ru4(CO)10(PPh3) (p4-Te)2 has been de~cribed.'~' The reaction of tetrakis(triphenylphosphine)palladium Pd( PPh3)4 and triethylphosphine telluride Et3PTe in toluene at room temperature has been found"' to produce the compound (Et3P),Pd2Te2 which contains a simple Pd2Te2 four-membered ring and a larger molecular compound (Et3P),Pd,Te6 which was described as an eight-membered ring that is twice bridged by (Et3P)2PdTe units. These clusters were shown to be intermediates in an organometallic synthesis of PdTe.Three isopleth sections AgTlTe-( CuTlTe) AgTlTe-Cu2Te and AgTlTe-Cu2TlTe2 of the quaternary system Ag-Cu-T1-Te have been in~estigated'~~ by thermal analysis differential scanning calorimetry and X-ray powder diffraction. The AgTlTe-based solid solution (Ag,Cu T12Te) limits were determined and the composition-structure I48 R. A. Wheeler J. Am. Chem. SOC.,1990 112 8737. I49 P. Mathur I. J. Mavunkal V. Rugmini and M. F. Mahon Znorg. Chem. 1990 29 4838. I50 P. Mathur B. H. S. Thimmappa and A. L. Rheingold Inorg. Chem. 1990 29 4658. I51 J. G. Brennan T. Siegrist S. M. Stuczynski and M. L. Steigerwald J. Am. Chem. Soc. 1990 112 9233. G. Brun M. Boubali R. M. Ayral and J.-C. Tedenac J. Solid State Chem.1990 89 292. F. J. Berry relations depicted. The phase diagram of Cd2,(CuIn),Mn,Te2(x + y + z = 1) alloys have been determined.'53 The synthesis of an unusual free organotelluride anion and the metal complex [Ag,(TeR),]'- (R = thienyl) has been de~cribed.'~ The preparation and crystal structure determination of Nd2Te40 has been 1-ep0rted.l~~ The structure of the rare earth tellurium oxide was described in terms of an interconnecting network of distorted square anti-prisms which link in two dimensions through edge sharing with TeO polyhedra which link in the same two dimensions through corner sharing. Sheets of (Nd2010),join with those of (TesOzo) to form a three dimensional network. The location and role of the lone pairs was discussed and the structure described in terms of a distorted hcp array of oxygen ions neodymium ions and lone pairs in which tellurium ions occupy selected trigonal bipyramidal sites.M. Quintero E. Guerrero R. Tovar G. S. Perez and J. C. Woolley J. Solid State Chem. 1990 87 456. IS4 J. Zhao D. Adcock W. T. Pennington and J. W. Kolis Inorg. Chem. 1990 29 4358. IS5 A. Castro R. Enjalbert D. Lloyd 1. Rasines and J. Galy J. Solid State Chem. 1990 85 100.