The stereochemistry of pentavalent antimony compounds

Abstract

A survey of the crystal chemistry of simple and complex pentavalent antimony compounds is presented. It follows from the analysis of structural data that "closed" polyhedra with coordination numbers 4, 5, and 6 without additional bonds of antimony with farther removed atoms are, as a rule, formed around the pentavalent antimony atom. The coordination number four with a tetrahedral configuration is extremely rarely encountered. The coordination number five with the configuration of a trigonal bipyramid is characteristic for simple halides and also for organometallic compounds of pentavalent antimony. The coordination number six (octahedral form) is found in complex halides, halides with additional donor ligands, and likewise in all oxygen compounds. The interatomic Sb-ligand distances in the trigonal bipyramid are non-equivalent: the bonds to the three ligands located in the equatorial plane of the molecule are more stable than those to the two "peaks." The Sb-halogen distances in octahedral complexes may vary over a wide range even when the "bridge" atoms are excluded from consideration. The scattering of interatomic Sb-O distances in the oxygen compounds, is, as a rule, small.