Mid-, far-infrared and raman spectra of uranyl complexes in aqueous solutions

Abstract

Vibrational spectra have been obtained for aqueous solution of UO 2C10 4, Na 3[UO 2F 5], [NH 4] 3[UO 2F 5], UO 2F 2, [Bu 4N] 2[UO 2Cl 4], UO 2Cl 2, UO(NO 3) 2, Rb [UO 2(NO 3) 3], [Pr 4N] [UO 2(NO 3) 3], UO 2(O 2CCH 3) 2, [Pr 4N] [UO 2(O 2CCH 3) 3] and UO 2SO 4 over a range of solution composition. The residual absorptions of H 2O after water subtraction suggest that some water molecules are bound to [UO 2] 2+. There was no evidence of perchlorate coordination, but besides solvated [UO 2] 2+ ion formation of weak [UO 2F] + and [UO 2Cl] + complexes have been established. The four nitrate stretching features do not refer neither to bidentate nor to monodentate ligand, but both monodentate and bidentate linkage of acetate to uranyl were established for acetate complexes. The main species present in UO 2SO 4 solution can be ascribed to a monodentate sulphate. From uranyl frequencies force constants and UO bond distances were calculated for solvated complexes.