Kinetics of the formation of precipitates and the physicochemical properties of technetium-99 and rhenium sulfides according to small-angle X-ray scattering and ultramicrocentrifugation data

Resumo

The interaction of technetium and rhenium with sulfides in aqueous solutions was studied by small-angle X-ray scattering and ultramicrocentrifugation. It was shown that, although the stoichiometry of technetium sulfide corresponds to the formula Tc₂S_7–x, the oxidation state of technetium in it is +4 and the excess sulfur is bound into a disulfide group so that its formula can correctly be written as [Tc₃(µ³-S)(µ²-S₂)₃(S₂)_(3n–n)/n)]_n. The determination of the solubility of technetium sulfide is complicated by its tendency to form colloids, which was the reason why the above methods were chosen to find features of its formation and describe its solubility in solutions.