On the Role of d Orbital Hybridization in the Chemistry Curriculum

John Morrison Galbraith

Department of Chemistry, Biochemistry, and Physics, Marist College, Poughkeepsi, NY 12601

Abstract

Modern valence bond theory has been used to enforce sp³d² hybridization in SF₆. Alternative bonding schemes with no d-orbital contribution are presented and yield lower total energies in agreement with previous studies discounting the role of sp³d² hybrid orbitals. Therefore, the use of d-orbital hybridization to describe hypervalent molecules should be removed from the general chemistry curriculum. Instead, bonding in SF₆ can serve as a good example of the role of theory in chemistry, nicely illustrating that no theory provides all the right answers all the time. More detailed valence bond and molecular orbital descriptions can be reserved for advanced courses. A more in depth look at SF₆ highlights the similarities between molecular orbital and valence bond theories and the importance of resonance mixing of covalent and ionic valence bond structures as well as fragment orbital mixing in order to make delocalized molecular orbitals.

Journal of Chemical Education, 2007, 84, 783                  Full Text (PDF)

-- ThanhTruong - 11 Jul 2007