Infrared and polarized Raman spectra of Cu(HSeO3)2 · H2O single crystal

Abstract

Infrared and polarized Raman spectra of Cu(HSeO3)2 · H2O single crystal have been recorded and analysed. The appearance of non-degenerate SeOH stretching vibrations in the αxz and αyz polarizations of Raman spectra indicate distortion of the HSeO3− ion in the Cu(HSeO3)2 · H2O crystal. The low wavenumber values obtained for the symmetric and asymmetric stretching vibrations of the HSeO3− ion are consistent with the strong hydrogen bonding and the influence of Jahn-Teller distortion as predicted in X-ray diffraction data. The shifting of the stretching and bending vibrations of the hydroxyl groups and water molecules from the free state values also confirms the strong hydrogen bonding in this crystal. Broad bands observed for both stretching and bending regions become sharp in the Raman spectrum recorded at 77 K. A doublet appears for the SeOH stretching mode at this temperature indicating the settling of protons in an ordered position and the absence of intrabond proton tunnelling.