Other Gallium Compounds

Other Gallium Compounds.—Thermodynamic parameters for GaSb and GaSb2 have been obtained from high-temperature mass-spectrometric measurements.543 

X-Ray and other studies on the solid solutions Gai xGexCr3N have elucidated the various structural changes which occur with temperature.544 

Mo6Gan is monoclinic, and belongs to a new structure type.545 The chief structural units are MoGai0 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. 

Nardin, G. Lorthioir, and R. Fruchart, Bull. Soc. chim. France, 1973, 2959. 

and mass spectral data are consistent with the structure (75).548 

Other Gallium Compounds.—Phase relationships in the V-Fe-Ga and V-Mn-Ga systems have been elucidated.  

VsGa4i belongs to the rhombohedral space group R3, and the unit cell contains one Ga(VGas)8 unit. One Ga is in the centre of a cuboctahedron of Ga atoms, whose triangular faces are each shared by the face of a VGa o polyhedron. This latter is formed by 10 triangular and three nearly square faces, and corresponds to half an icosahedron and half a cube. ° 

CrsGa4 and Fe3Ga4 are isomorphous, crystallizing in the space group C2/m. Ni2GaGe possesses an orthorhombic crystal structure, related to CoSn. PtsGa has a crystal structure which is a variant of the CU3AU structure. 

Other Gallium Compounds.— Phase diagrams of the systems MgSeg-GagSes, (M = La, Nd, Gd, or Y) have been obtained. Two types of intermediate phases were observed MeGaio/aSej (hexagonal, M = La—Gd) and MGaSe (orthorhombic, M = Gd— Dy). 

A study of the Ga-Mg phase diagram has confirmed the existence of the compound MgaGas.  

The Mo-Ga system has been studied by thermal analysis, JST-ray diffraction, electron microprobe, and metallography. Two intermetallic compounds were identified and characterized as follows a) MosGa, peritectic (1820 20 °C), (h) MoGas, peritectic (835 db 5 °C). 

The phase diagram of CuaTe-GagTeg has been determined. A compound CuaGa4Te7 is formed which is a defect sphalerite-type semiconductor (energy gap 1.08 0.05 eV). 

Other gallium-based III-V compounds are also produced by CVD, either experimentally or in production. The major ones are listed in Table 13.4. 

The many possible combinations of II-V and II-VI compounds allow the tailoring of electronic and opto-electronic properties to suit specific applications. Of particular importance is the control of the stoichiometry of the element involved. This is achieved by the proper handling of the MOCVD reactions. Being able to tailor the bandgap imparts great flexibility in the design of transistors and optoelectronic devices. 

Most of these compounds were originally prepared by liquid-phase epitaxy. That process is now largely replaced by MOCVD, particularly in the case of gallium arsenide, gallium arsenic phosphide, and gallium aluminum phosphide. 

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Variable coordination modes in compounds of similar general formula but different compositions (heterogeometrism) has been observed in the case of gallium and indium diisobutyldithiophosphinate pair, M(S2PBu12)3, M = Ga or In the gallium compound is four-coordinate, distorted tetrahedral, whereas the indium compound is six-coordinate, distorted octahedral (Scheme 7).134 Other... 

CH3)3N GaH3, (CH3)3P GaH3 [15279-03-5], and (CH3)2N GaH2 [32342-80-6], These are used for the preparation of other oiganic compounds of gallium. 

A thermographic material with only one heat-sensitive component is prepared by reaction of an organometallic compound such as phenylmercury(II) nitrate with a thiourea derivative.230 The product is ball milled and coated in a binder such as poly(vinyl acetate). Other organometallic compounds disclosed are those of bismuth, tin, gallium and germanium combined with a variety of sulfur-containing compounds such as thioamides and xanthates. 

Only recently, however, with the isolation and more detailed interrogation of the compounds [Me2GaH] (47) and HGa(BH4)2 (48-50), has it been possible to discover with any sureness the properties—including the structures—of such compounds. Insofar as these properties have a bearing on the hunting of other gallium hydrides, it will be better that we elaborate on them in due course (in Section IV). 

The last 25 years have seen the synthesis of a number of remarkable aluminum and gallium compounds containing the metals in the -K and -Ell oxidation states. Although some of these compounds do not contain true low-valent metal centers, others do contain... 

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