Correlation between the observed infrared stretching frequency and the bond character of the Si–H bond

It is shown that the empirical correlation between the infrared (IR) stretching frequency of the Si–H bond in substituted silane molecules (SiH3R1, SiH2R1R2, and SiHR1R2R3 with Ri the substituted molecular fragment) can be understood on a fundamental basis as the dependence of frequency on the bond order (S component) of the bond.