Observed and DFT-calculated IR spectra of n-Bu4M (M = Si, Ge, Sn, Pb), (CEI3CH2CH2 (CD2)-C-13)(4)Sn, and n-BuAuPPh(3)d(15) are reported and assigned. The asymmetric CH stretching vibration of the CH2 group adjacent to the metal atom appears as a distinct shoulder at similar to 2934 cm(-1), whereas for other CH2 groups it is located at similar to 2922 cm(-1). The characteristic peak at similar to 2899 cm(-1) is attributed to an overtone of a symmetric CH2 bend at similar to 1445 cm(-1). In n-BuAuPPh3-d(15) the CH stretching vibrations of the butyl group are shifted to lower frequencies by similar to 10 cm(-1), and two possible rationalizations are offered.