Uranous iodide

U is also found in the Soviet Union where there are sources in Karelia, near Dnepropetrovsk, the Kirghiz Soviet Republic and in Transcaucasia Whereas once U ores were processed for their Ra content, Ra has now lost its commercial importance and it is considered a contaminant. Only two U ores have been processed extensively, pitchblende and carnotite. The general procedure is to solubilize the U with an acid, convert the ion to a complex carbonate (thereby removing the Fe, A1 and Mn), ppt the Pb and Cu as the sulfide, and finally, to recover the U as the ammonium uranate and hence, as the oxide U metal can be obtained from the oxide or the halide by reduction with alkali metals or alkaline earth metals. U, being highly electropositive, cannot be deposited electrolytically from aq solns. Thermal decompn of the tetra-iodide is possible (Ref 1)... 

Haissinsky and Duflo 18) and Preve and Montamal 19) report similar phenomena. They have studied, among other reactions, the benzene oxidation in alkaline solution, yielding phenol, the potassium iodide oxidation in aqueous solution, and the uranous sulfate oxidation in aqueous solution. 

In the case of potassium iodide and uranous sulfate oxidation induced by radiation, the effect of the presence of various solids such as CoS, Th02, and Nb206, which are catalysts for these reactions in the absence of radiation, has been investigated. The increase of the oxidation of uranous sulfate always remains small, and never exceeds a factor of two, whereas in the case of potassium iodide oxidation the presence of ThOa increases the G from 3.2 to 10. For purposes of general interpretation these authors resort to the above mentioned Vesselovsky theory. 

Pure uranous compounds may be prepared by precipitating U(OH)4 from aqueous solution with ammonium hydroxide and dissolving the precipitate in the appropriate acid. Uranous sulfate, the most common salt, is soluble in water, as are the chloride, bromide, and iodide. Uranous nitrate is unstable, gradually undergoing oxidation to uranyl nitrate with liberation of oxides of nitrogen. 

Tetravalent plutonium in aq soln is reduced to the trivalent form by sulfur dioxide, hydroxylamine hydrochloride, hydrazine hydrochloride, the uranous ion, the iodide ion by shaking with mercury in chloride soln electrolytically at a platinum cathode. Tetravalent salts are pink or greenish form complexes very readily. 

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