Theoretical Aspects of Main Group Multiple Bonded Systems

Abstract

Computational data on homonuclear multiple bonding between elements of group 13 and heavier elements of group 14 are reviewed. For R n EER n , there is an increased tendency of bending the RER planes ( n = 2) or the RE bonds ( n = 1) toward the EE axis upon descending a group. This is related to the mixing of the valence σ–π orbitals reflecting the tendency of the heavier elements to retain nonbonding character for their n s 2 orbital. As a result, the bond orders are also reduced and the EE interaction weakened.