Interpretation of the terminal ν(CO) spectra of some M5 transition metal carbonyl clusters

The ν(CO) spectra of 31 M5 transition metal carbonyl clusters are interpreted in terms of the spherical harmonic and tensor harmonic models. It seems that the former is that which is generally applicable but that the splittings of the (spherical) P mode are larger than had previously been considered indicative of this model. An explanation in terms of the cluster asymmetry is suggested.