Recent developments in the bond valence model of inorganic bonding

The valences of bonds can be predicted from the bonding network using (by analogy with electrical networks) Kirchhoff-like equations which lead to the definition of a new atomic property, the Valence Potential. The computer algorithm used in this prediction indicates that the electrons on any ion tend to be shared equally between all the bonds and that, despite appearances to the contrary, the rules of bonding around cations and anions are identical. These rules are the basis of a number of structure prediction and modelling techniques which make use of the correlation between bond valence and bond length. A three parameter equation is proposed to describe this relation for those bonds (e.g. H-O, Na-O, Tl-O) which occur with a wide range of lengths and for which, therefore, the usual two parameter equations are not adequate.