Domain-averaged Fermi holes -: a new means of visualization of chemical bonds.: Bonding in hypervalent molecules

The nature of bonding in several hypervalent molecules was analyzed at the uh initio SCF level using the recently proposed methodology based on the analysis of domain-averaged Fermi holes. The results of the analysis demonstrate that, for sufficiently flexible basis sets. the expansion of the valence shell does indeed take place for second row central atoms in PF5, SF4, and SF6. On the other hand, no such expansion was observed for the first row N atom in NF5.