Knowledge Bank

The vibrational spectra of various pentahalide metal complexes including $NbCl5,NbBr5,MoF5$ and $MoCl5$ have been interpreted in details through normal coordinate analysis based on $D3h$ symmetry. The obtained values of force constants for each compound indicate the weakening of the axial M-X' compared with the equatorial M-X bonds. These values are discussed in view of the donding and structures of these compounds.