A study of uranium speciation in acetate solutions at temperatures from 25 to 250 degrees C

We report U L3-edge XAS analysis results from a study of the speciation of U(VI) in acetate solutions between 25 and 250 degrees C, at pH's between 1.82 and 2.57 and [acetate]:[U] ratios of 0.5 to 50. At 25 degrees C in excess acetate there are at least two acetate ligands in the equatorial plane with a U-O bond distance of 2.44 A. At elevated temperatures with excess acetate, acetate is still coordinated but the speciation mixture appears more complicated. Less evidence exists for acetate coordination when [acetate]:[U] ratio is unity or below. pH within this limited range appears to have little effect on the uranyl speciation.