The Raman Spectra of Some Thermochromic Tetraiodomercurates

Abstract
The Raman Spectra of the thermochromic tetraiodomercurates of Ag(I), Cu(I), Hg(I), Tl(I), Hg(II) and Pb(II) have been obtained below and above the transition temperature. The spectra are interpreted in terms of the known crystal structures. The Hg2HgI4 shows an interesting behaviour towards light irradiation which has been interpreted in terms of mixed valence states model.