Pseudo one-electron bonds and atomic valencies for some increased-valence and non-paired spatial orbital valence bond structures

Abstract

The expression for the A-atom valence is reformulated for the one-electron A-Y bond of the valence-bond structure Y ̇ ·A–B with a ( y) 1( ψ ya ) 1( ψ ab ) 2 orbital configuration. With atomic orbital overlap integrals omitted from all normalisation constants, it is calculated that the maximum value for the A-atom valence 1.354, is almost identical to the value of 1.352 reported previously [Theochem. 634 (2003) 265]. The theory is applied to the non-paired spatial orbital structure Y ̇ ·A· B ̇ with a ( y) 1( ψ ya ) 1( ψ ab ) 1( b) 1 configuration, to obtain a maximum value of 1.155 for its A-atom valence. Thus relative to the Lewis structure Ÿ A —B, both valence-bond structures exhibit increased-valence or electronic hypervalence. The V ay for the increased-valence structure, and either the V ay or the V ab for the non-paired spatial orbital structure, can range between 0 and unity in value. Therefore their associated one-electron bonds are pseudo one-electron bonds.