The Bond Valence Model as a Tool for Teaching Inorganic Chemistry: The Ionic Model Revisited

The ionic model is shown to give a good description of most inorganic materials, such as salts, ceramics, and minerals, regardless of the covalent or ionic character of their bonds. The virtue of the model is its ability to treat chemical bonding using simple electrostatic theory, all the quantum mechanical effects being contained in a short-range potential that is treated empirically. By exploiting the properties of the electrostatic field, a rigorous but simple and intuitive bond model is developed (the bond valence model).This paper shows how the model can be used to explore the structural, chemical, and physical properties of inorganic compounds, including their stability and solubility. The online version of the paper explores further application, showing how the model can be used to understand hydrogen bonding, the factors that determine coordination number, and the unusual chemistry and physics of the new high-tech inorganic solids. The simplicity of the model, the insights it provides without the need for extensive computation, and its wide range of applicability make it particularly useful in teaching as well as research.