Theoretical chemistry of the 7p series of superheavy elements II. the relativistic molecular orbital and Kappa Valence methods

Abstract

The relativistic generalizations of both molecular orbital and spin-valence (the Kappa valence method) theories are used to investigate the covalent bonds that can be formed by the ground relativistic configuration of a heavy element containing a non-closed subshell of p ¯ or p valence electrons. Both theories predict that p ¯ -H and p -H bonds are not greatly weakened compared with normal covalent α bonds and that covalent com pounds based on the p 2 relativistic configuration will be bent with an equilibrium interbond angle of 90°. Both p ¯ -H and p-H bonds are predicted by the Kappa valence method to be a mixture of a normal covalent a bond and the triplet bond formed by the interaction of two electrons occupying orthogonal orbitals. This method predicts that the bond formed between a heavy element and a group of rather different electronegativity may be weakened by relativity more than a p ¯ -H or p-H bond because only the non-orthogonal Heitler-London singlet portion of such a bond can be stabilized by ionic-covalent resonance.