Predicting the Stability of Hypervalent Molecules

Tracy A. Mitchell, Debbie Finocchio, and Jeremy Kua

Department of Chemistry, University of San Diego, San Diego, CA 92110

Abstract

In this exercise, students use concepts in thermochemistry such as bond energy, ionization potentials, and electron affinities to predict the relative stability of two hypervalent molecules (PF₅ and PH₅) relative to their respective non-hypervalent counterparts. Students will use experimental data from the Internet as well as collected data from their own computer calculations. A novel part of this exercise is to predict a priori if a hypervalent molecule should be stable based only on information gathered from stable non-hypervalent molecules. In addition, students will see how resonance structures can successfully describe bonding in hypervalent molecules without exceeding the octet rule.

Journal of Chemical Education, 2007, 84, 629                             Full Text (PDF)

-- ThanhTruong - 11 Jul 2007