THE NEARLY OCTAHEDRAL HEXAMETHYLSULFUR AND HEXAMETHYLSELENIUM MOLECULES - LIGHTER COUNTERPARTS TO THE RECENTLY SYNTHESIZED HEXAMETHYLTELLURIUM

Self-consistent-field molecular orbital theory has been applied to the hypervalent molecules hexamethylsulfur and hexamethylselenium. Using a double-zeta basis set augmented by d-like polarization functions on the central atom, one minimum of D3 symmetry is predicted for each com pound. It is noted that these minima are only slightly distorted from octahedral ligand coordination. Molecular geometries, vibrational freq uencies, and infrared intensities are predicted. Comparisons are made between these predictions and the predictions from the same level of t heory applied to the dimethylchalcogens. The results of a preliminary investigation of hexamethyltellurium are also included.