Symmetry Rule for Predicting the Structures of Molecules. II. Structure of X2Yn Molecules

Using the second-order Jahn–Teller effect as a criterion, molecular shapes are predicted for molecules with the formulas X2Y2, X2Y4, and X2Y6. The method is remarkably successful, the only failure being the inability to predict the correct angle of rotation about single bonds. However, this is a necessary failure.