Gallium salts

Gallium sesquioxide is precipitated in hydrated form upon neutralization of acidic or basic solution of gallium salt. Also, it is prepared by thermal decomposition of gallium salts. Gallium oxide hydroxide, GaOOH [20665-52-5] on calcinations at high temperatures yields beta- Ga203. 

In general, the electrodeless lamp contains a small amount of mercury and a neutral starter gas. The mercury pressures during its operation are in the 5-20 bar range, which is higher than for arc lamps, with pressures only in the 1-2 bar range. The characteristics of fhe lamp can be modified by fhe addition of mefal halides in confrolled quanfifies to the gas. The frequently used D or V lamps contain iron or gallium salts, respectively. Some characteristics of microwave-powered lamps are in Table 3.1. 

The purification of the gallium salt solutions is carried out by solvent extraction and/or by ion exchange. The most effective extractants are dialkyl-phosphates in sulfate medium and ethers, ketones (qv), alcohols, and trialkyl-phosphates in chloride medium. Electrorefining, ie, anodic dissolution and simultaneous cathodic deposition, is also used to purify metallic gallium. 

It should be pointed out here that all the platinum complexes which are active anticancer agents are also efficient inducers. Those complexes which are not active, do not cause lysis. So far, there is a complete isomorphism between the set of active anticancer complexes and the set of efficient inducers. Earlier, we had believed that a good correlation existed between anticancer active complexes and the filament-forming complexes. After a while, however, exceptions in both classes occurred which decreased our faith in this correlation. The correlation of lytic induction and anticancer activity has held up well. In fact, when R. Adamson at the National Cancer Institute reported the anticancer activity of gallium salts, we tested these and, indeed, they did induce lysis in lysogenic bacteria. 

While the tetrahaloaluminates are unstable under acid conditions, the gallium analogs are readily extracted from aqueous solutions of gallium salts, into ethers, by 8M HCl the resulting ether phase contains [GaCL ] ions. This suggests the presence of a series of equilibria (equation 25) ... 

Extraction.2 — (a) To extract gallium from an ore, the material is ground to a fine powder, dissolved in aqua regia, and the excess acid expelled by heating. Cool, add zinc, and filter off the precipitated metals, then boil for a long time with zinc, when a basic gallium salt is precipitated along with aluminium, iron, zinc, etc. 

Rasey JS, Nelson NJ and Larson SM (1981) Relationship of iron metabolism to tumor cell toxicity of stable gallium salts. Int J Nucl Med Biol 8 303 —... 

Other onium salts described in the literature include tripenylpyrylium tetrakis(perfluorophenyl)gallate and antimonite, reported by Nickers et al., They are claimed to be efficient photoinitiators for the cationic polymerization of epoxy compounds. The gallium salt can be illustrated as follows ... 

The gallium salt produces long-chain polyphosphate as well ... 

The stable oxide is Ga Oj, gallic oxide. This is soluble in HCl, H SO, and aqueous alkali hydroxide and ammonia, but if it has been previously strongly heated, it dissolves in these media only extremely slowly. Barium carbonate precipitates the hydroxide from aqueous solutions of gallium salts. The hydroxide dissolves is aqueous acids and alkalis. 

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