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 an alysis of domain-averaged Fermi holes. The results of the analysis demonstr ate that, for sufficiently flexible basis sets. the expansion of the valenc e shell does indeed take place for second row central atoms in PF5, SF4, an d SF6. On the other hand, no such expansion was observed for the first row N atom in NF5.