The vibrational frequencies of Si–H groups, SiH, SiH2, and SiH3, in substituted silane molecules, and hydrogenated amorphous solids, display shifts in frequency that can be correlated with the relative electronegativities of the silicon nearest neighbors, i.e, the substituting atoms or groups in the molecules, and the hydrogen second neighbors in the amorphous networks. In this paper, the empirical relations are extended to include a description of Si–H vibrations on semiconductor surfaces.