Gallium metal

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). 

A gallium metal-mediated allylation of pyrrole led selectively to the formation of the 3-substituted pyrroles <06TL3535>. In contrast, a palladium-catalyzed allylation of pyrrole with allylic alcohols performed in the presence of triethylborane led to 2-substituted pyrroles <06H(67)535>. 

By dissolving gallium hydroxide in caustic potash, and electrolyzing the solution with a current from five or six Bunsen cells, Boisbaudran prepared more than a gram of gallium metal. This was first prepared in November, 1875. On December 6th he presented 3.4 milligrams of solid gallium (14) to the Academy of Sciences, and three months later he... 

H2GaNH2)3 at 500 °C produces nanocrystalline GaN with a significant impurity of gallium metal.The nanocrystalline material slowly converts to the wurtzite phase at 900 °C. Since dimethylhydrazine H2NNMe2 decomposes at much lower temperatures than ammonia, the dimeric four-membered ring (H2GaNHNMe2)2 has also been considered as a precursor to GaN. ° ... 

Purification. Extraction from aluminum or zinc ores produces cmde gallium metal or concentrates. These concentrates are transformed to sodium gallate, gallium chloride, or gallium sulfate solutions which are purified, then electrolyzed. Gallium is deposited as a liquid. 

KEY CONCEPT PROBLEM 10.19 Gallium metal has the following phase diagram (the pressure axis is not to scale). In the region shown, gallium has two different solid phases. 

PROBLEM 14.3 Write a balanced net ionic equation for the reaction of gallium metal with dilute acid. 

Gallium metal is soluble in liquid gallium(II) chloride. 

The electrodeposition of gallium is of interest for its extraction and purification and for the production of III-V semiconductors. Sun et al. were the first to report the electrodeposition of gallium from Lewis acidic aluminum chloride-1 -ethyl-3-methyl-imidazolium chloride melts (ratio 60 40 mol%) on tungsten and glassy carbon in 1999 [14] The Ga(I) species was introduced by anodization of the gallium metal. 

Allylgallium and propargylgallium compounds can be prepared by the direct reaction of the corresponding bromides or iodides with gallium metal.402,403Gallium enolates are also prepared from a-halo carbonyl compounds with gallium.404... 

Lodding, A. Electrotransport and Effective Self-Diffusion in Pure Liquid Gallium Metal. J. Phys. Chem. Solids 28, 557 (1967). 

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