The combination of the three types of vibrational spectroscopy, infrared, Raman, and inelastic neutron scattering, has enabled all of the internal, and most of the external, modes of Mg2FeH6 and Mg2FeD6 to be observed and assigned, as well as some of the modes of Mg2FeD5H. As an aid to the assignment, a reliable, empirical force field has been developed. The spectra also show evidence for a dynamic distortion of the hexahydrido complex, an effect that is not observed for the deuterated species.