Configuration of the SO=4 ion in the cubic phase of Li2SO4 from band shape studies of the ν3 mode

Abstract

A Raman spectroscopic study of the molecular ν3 band in the plastic phase of Li2SO4 is presented. The analysis of the band shape and the depolarization ratio vs frequency suggests a prevalence of C3v configurations around the sulfate tetrahedra. Spectroscopic evidence from the pretransitional region in the monoclinic phase and a similar analysis of the ν3 band in the melt reinforce this hypothesis. These data are compared with structural results and a computer modeling of the possible orientational distribution of the SO2−4 tetrahedra in the plastic phase.