Lone Pairs of Electrons

The theory developed so far explains only the bonding pattern and shapes of molecules whose electronic structure consists of just two types of substructure: atomic cores and single bonds. This is not enough. The idea of a ‘lone pair’ of electrons is all-pervasive as a factor in the theory of the shapes and reactivities of molecules. It proves to be just as necessary to understand the effect that bond formation has on the ‘non-bonding’ electrons of atoms as it is to have a theory of how chemical bonds form.