The Rise and Fall of Classical VB Theory

The simple mathematical machinery developed in the last Section was used to great effect, throughout the thirties and forties, in applications ranging from the prediction of molecular geometries and the estimation of heats of formation to the detailed discussion of bond properties and even to the theoretical study of chemical reactions. In all these areas Pauling was a leading pioneer. 

To illustrate such applications and to introduce other important developments during this period, one example must suffice, namely that provided by the water molecule. 

Let us start by listing the guiding concepts underlying the application of VB theory in its classical form  

The inherent defects of VB theory in its classical semi-empirical form are closely related to the premises listed above. They are  

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