The hydrolysis of uranium(VI) in sulfate media

The hydrolysis of uranium(VI) has been investigated in 0.10 and 1.0 mol dm(-3) Na2SO4 using the potentiometric titration technique. Analysis of the data indicates the presence of the following uranyl hydrolysis species: (UO2)(2)(OH)(2)(2+), (UO2)(3)(OH)(4)(2+), (UO2)(4)(OH)(7)(+) and (UO2)(5)(OH)(8)(2+) in both media, and additionally, UO2OH+ and (UO2)(3)(OH)(5)(+) in the lower ionic strength only. The data were used to calculate stability constants for ternary uranyl hydroxo-sulfate complexes. These constants were found to be in excellent agreement with those found in an earlier study at a higher Na2SO4 concentration (1.5 mol dm(-3)).