Myths and reality of hypervalent molecules. The electronic structure of FClO(x), x = 1-3, Cl3PO, Cl3PCH2, Cl3CClO, and C(ClO)4.

In the present work we examine a series of hypervalent molecules, namely, FClO(x) (x = 1-3), Cl(3)PO, Cl(3)PCH(2), Cl(3)CClO, and C(ClO)(4), through single-reference [CCSD(T)] and multireference (MRCI) ab initio methods, the principal aim being the deciphering of their binding pattern. Our electronic structure calculations consistently show that the bonding occurs through an electron pair transfer from the Cl or P atoms of the molecules considered to the (1)D state of the O atom(s). We strongly believe that the term "hypervalency" when viewed from an unbiased side and with a critical eye reveals a simple chemical bonding situation that is in conformity with a scientific parsimony that dissolves the mythology of an enormous class of molecular systems that are categorized under the term hypervalent.