Electron density distribution, polarizability and bonding in the octahedral clusters 6Mo6S8(CN)696$minus;, 6Re6S8(CN)694$minus; and Rh6(CO)16

Abstract

The geometrical structure and bonding in [Mo6S8(CN)12]6−, [Re6S8(CN)6]4− and Rh6(CO)16 clusters were studied on the basis of quantum chemical calculations. The main attention was paid to the study of electron density distribution and polarizabilities for these compounds. There is noticeable electron density in the inner part of the M6 octahedrons as well as on the edges and faces of the M6S8 polyhedrons. These observations lead to a model of the electronic structure of the clusters with octahedral cores, in which the mobile electrons are moving in a potential well of spherical symmetry. The resulting one electron states are classified according to the orbital quantum number l (1s, 1p, 1d, 1f and so on). Subsequent crystal field splitting leads to a calculated succession of one electron states of Oh point group symmetry. The high values of the calculated polarizabilities of the compounds under consideration are in accord with the suggested model.