Raman Spectra of Liquid MgCl2 and Liquid MgCl2–KCl System

Abstract

Raman spectra of molten MgCl2, MgCl2–KCl, and MgCl2–2KCl were recorded, at 730°, 525°, and 475°C, respectively, using a Cary 81 Raman spectrophotometer. Liquid MgCl2 exhibits three Raman lines with frequencies 269, 214, and 142 cm−1, which are explainable on the basis of the presence of MgCl64— ions with octahedral configuration. Liquid MgCl2–KCl exhibits four Raman lines with frequencies 451, 250, 208, and 158 cm−1; and their polarization characteristics indicate the existence of MgCl3− ions with pyramidal configuration C3v. The Raman spectrum of liquid MgCl2–2KCl is almost similar to that of liquid MgCl2–KCl. Force constants for the various Mg–Cl ionic species were calculated using generalized valence forces.