Raman spectroscopic evidence for colinear arrangement in the solid state of thermochromic distibanes

Abstract

The IR and Raman spectra of the compounds (CH3)2Sb-Sb(CH3)2 (I), [(CH3)3Si]2Sb-Sb[Si(CH3)3]2 (II), [(CH3)3Si]2As-As[Si(CH3)3]2 (III) and (C6H5)2Sb-Sb(C6H5)2 (IV) have been studied in the liquid and solid states. Given assignments for I to III are based on normal coordinate analyses, and force constants are reported. The solid state Raman spectra of I and II exhibit strong lines near 50 cm−1, which are assigned to the longitudinal acoustic mode of an infinite linear chain of Sb atoms. Intermolecular Sb…Sb force constants, 0.125 and 0.18 N cm−1, are determined for I and II respectively.