The Vibrational Spectra and Rotational Isomerism of Methylvinylsilane and Allylsilane

Abstract
The infrared and Raman spectra have been measured for methylvinylsilane, CH2=CHSiH2(–D2)CH3, and allylsilane, CH2=CHCH2SiH3(–D3). The fundamental vibrations have been assigned, and the normal coordinate treatment for possible molecular forms has been carried out. For methylvinylsilane, the cis and skew forms coexist in the gaseous and liquid states, while only the former persists in the solid state. In the liquid state the cis form is more stable by 0.66±0.05 kcal/mol than the skew form. For allylsilane, the form near the skew form predominantly exists in the gaseous, liquid, and solid states.