The Raman and far-infrared spectra of some solid selenium and tellurium tetrahalides

Abstract

The Raman and far-infrared spectra of solid selenium and tellurium tetrachlorides and tellurium tetrabromide are reported. The infrared spectra of selenium tetrabromide and the mixed halides SeClBr₃ and SeCl₃Br were also studied. Three possible structures for these compounds were considered: a simple ionic formulation MX₃⁺X^– of C_3v symmetry, a covalent MX₄ molecule of C_2v symmetry, and a distorted ionic structure of C_s symmetry resulting from interionic charge-transfer. The vibrational spectra suggest a C_2v covalent structure.