The Use of Molecular Modeling and VSEPR Theory in the Undergraduate Curriculum to Predict the Three-Dimensional Structure of Molecules

Abstract

This paper illustrates how valence shell electron pair repulsion (VSEPR) theory and molecular modeling can be used in a complimentary fashion in the undergraduate curriculum to predict the three-dimensional structure of molecules. Students use the familiar VSEPR model to sketch the three-dimensional structures of molecules predicted by a comparison of the relative magnitudes of electrostatic repulsion between electron pair domains on the central atom. Despite the simplicity and elegance of the VSEPR model, however, students often have difficulty visualizing the three-dimensional shapes of molecules and learning the more subtle features of the model, such as the bond length and bond angle deviations from ideal geometry that accompany the presence of lone pair or multiple bond domains or that result from differences in the electronegativity of the bonded atoms, partial charges and molecular dipole moments, and site preferences in the trigonal bipyramidal electron geometry. Students therefore also employ a m...