The Raman Scattering of Uranyl and Transuranium V, VI, and VII Ions

The Raman scattering of U(VI), Np(VI), Pu(VI), Am(VI), and Np(V), Am(V) in HClO 4 solutions and Np(VII) in a NaOH medium is reported. Direct observation of the polarized ν 1 vibration (D ∞h symmetry) is observed for the transuranium MO 2 n+ ions in the V and VI oxidation states. The spectroscopic evidence is consistent with a linear MO 2 n+ structure for the Np(VII) ion in basic solutions. The trend of the ν 1 frequency and the MO stretching force constants with the oxidation is discussed and is correlated with the bond strengths and the stability of the MO 2 n+ ions.