Symmetry Coordinates and Force Field Analysis of a Heptamolybdate, Mo7O24, Model

Abstract

A complete vibrational analysis is performed for a heptamolybdate, Mo7O24, niodel of C2V symmetry. The symmetry coordinates are classified into those of (a) framework vibrations, (b) ligand vibrations, (c) framework-ligand couplings, and (d) interligand vibrations. A simple valence force field is estimated, and a relative scale for the force constants of the angles is pre­sented. Vibrational frequencies are calculated and the influence of inclusion of redundancies is investigated. The final result is compared with experimental data from infrared and Raman. In the calculation of species A1 a correlation is found to all except one of the polarized Raman frequencies.