Vibrational spectra and normal coordinate analysis of neptunium (IV) borohydride and neptunium (IV) borodeuteride

Abstract

Solid state, low temperature IR (25–7400 cm−1) and Raman (100–2600 cm−1) spectra were obtained for Np(BH4)4 and Np(BD4)4 from which most of the allowed fundamentals were assigned based on the Td molecular structure. Those assignments were used in a normal coordinate analysis to derive a simple force field using eight primary and five interaction constants. This field is very similar to those found for Zr(BH4)4 and Hf(BH4)4. Isotopic impurity, overtone, and combination bands were identified in the IR spectra with the help of the normal coordinate calculations. Near IR spectra of Zr(BH4)4 and Zr(BD4)4 were taken in the range 7400–4000 cm−1 and the observed absorption bands were assigned as either overtone or combination levels.