The Infrared Spectra of the Methyl Chlorosilanes

Abstract

The infrared spectra of the series SiCl₄ through SiMe₄ have been obtained in the gas phase over the range 2–25 microns using CaF₂, NaCl, and KBr prisms. The spectra are compared with Raman data for these compounds, and vibrational assignments are made. The methyl band at about 8 microns is shown to be associated with the symmetrical CH₃ deformation, the bands around 12 microns with the methyl rocking and Si–C stretching vibrations, and the bands between 16 and 25 microns with the SiCl stretching modes. A comparison of frequencies for the members of the series has made it possible to assign fundamentals for all motions except those involving torsion of the Me group around its axis.