Infrared spectra in the SiH stretching region are reported for SiH3CH2Cl, SiHD2CH2Cl, SiH3Et, SiHD2Et, SiHDEtMe, SiHDEt2, SiHEt3, (SiH3)2CH2, (SiHD2)(SiD3)CH2, SiH3CH=CH2 and SiHD2CH=CH2 in the gas phase, and for SiH3CH2Cl, SiH3Et, SiHEt3 and SiHMe3 in hydrocarbon solvents. The presence of several types of SiH bond in the gas phase is diagnosed in all cases except those of disilyl methane and vinyl silane. These reflect the differing β effects of halogen and methyl groups. For the alkyl silanes, νSiH = 2125.8 + 41.0 Σσ*, for selected frequencies.

SiH stretching overtones have been studied in the infrared spectrum up to Δν = 5 for SiH4, (CH3)2SiH2 and (CH3) 3SiH and for Δν = 3 in CH3SiH3. The data for (CH3)2SiH2 and (CH33SiH necessitate a cubic term in the term value equation whose presence can explain the existing discordance between spectroscopically predicted and experimental values of Do(Si-H) in Methyl silanes. Earlier “local-mode” model predictions for the spectrum Of SiH4 are accurate with respect to frequencies, but not to intensity.