Gallium metal halides

The chalcogenide bromides and chlorides may be prepared by the reaction of the halide with the respective chalcogenide in a sealed ampoule. A mixture of gallium metal and chalcogen may be used, instead of the chalcogenide. The chalcogenide iodides are S3mthesized directly from the elements. The exact preparative conditions are listed in Table XVIII 160,165). 

Spectral outputs of some typical metal halide lamps compared to that of the standard mercury lamp mercury barrier discharge lamp (a) mercury barrier discharge lamp, (b) iron additive lamp, and (c) gallium additive lamp. (Courtesy of American Ultraviolet Company.)... 

The spectral output of the medium-pressure lamp can be altered by "doping," i.e., adding a small amount of metal halide to the fill material, with mercury. Commonly doped lamps are iron and gallium lamps. Medium-pressure lamps have long lifetimes (typically in excess of 3,000 h), although the intensity of the emitted light and the relative intensity of the spectral lines change with time. This affects their performance to the point that... 

A review of the chemistry of Group III complexes shows that many of the concepts of Werner s coordination chemistry may be applied to these elements. Furthermore, the differences observed in the complexing behavior between ammonia and trimethylamine refiect fundamental differences in the amines. Ammonia tends to give ionic compounds, whereas trimethylamine tends to give non-ionic products. Trends observed with the metal halides can be extrapolated into hydrides of boron, aluminum, and gallium. An extension of Werner s concepts provides a significant... 

Metal triflates can be easily prepared from metal halides and triflic acid at -78 C. They show several unique properties compared with the corresponding metal halides. In an early study, Olah reported the use of boron-, aluminum-, and gallium triflates [M(OTf)J as effective Friedel-Crafts catalysts. In the benzoylation and acetylation of toluene and benzene with acyl chlorides, the relative reactivity is boron triflate > gallium triflate > aluminum triflate, in agreement with the relative acidity strength. 

Electrolytic procedures employing gallium metal in the form of a sacrificial anode can also be conveniently used to synthesize salts of the gallium(Ill) complex halide ions, [GaX4]. A straightforward procedure described here involves electrolysis of gallium in aqueous acid, HX, followed by heating to oxidize any Ga(II) species to Ga(III) ... 

A mixed indium hydride halide complex, (l)TnH2Cl (29) has been prepared from the 1 1 reaction of [InH2Cl(NMe3) ] with carbene (1) (R = Mes, R = H), as shown in Scheme 2. The structure of (29) is monomeric with the geometry at the In center close to tetrahedral. The In-C distance (2.244(6) A) is similar to those observed in (28) (2.200(7) A) and (25) (2.253(5) A). A related mixed gallium hydride iodide complex (l)-GaH2l (30) has been isolated from the reaction of (26) with GaT, with concomitant deposition of gallium metal.Complex (30) is isostructural with the related indium complex (29) and has a Ga-C bond distance of 2.022(4) A. 

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