Information derived from a study of \u27isolated\u27 CH stretching
frequencies, measured in partially deuterated organic and organemetallic compounds, is reviewed. This includes CH bond lengths and dissociation energies, and HCH angles in methyl groups, Excellent agreement is found between CH bond length differences predicted from VCH\u27s values and those calculated by ab initio methods. V\u27sCH data also agree with the results of high overtone, local mode studies in distinguishing differences in CH bond strengths. The former however are based on spectra which are easier to assign
to specific bonds. They also enable one to understand the spectra
of normal, undeuterated molecules in the CH stretching region,
through \u27energy factored force field\u27 calculations. Reference is made to situations involvlng free internal rotation of methyl groups, and to studies of other \u27isolated\u27 MH bonds (M = N, Si, Ge, Sn)
