Structural Factors Involved in Ionic Adsorption

This paper deals with the adsorption of simple inorganic anions on metallic electrodes. Thesis was made that adsorption may be regarded as a co-ordination reaction similar to complex formation in solution. Pearson\u27s Principle of Soft and Hard Acids and Bases (SHAE) was applied. It suggests that adsorption i1s a typical soft co-ordination reaction (i. e. metal surfaces are soft acceptors) in which an electron pair on the anion is shared with a vacant orbital on a surface metal atom. Thus soft anions and electrodes with high cpJI or E. A. adsorb strongest. Variations in adsorption order of anions and electrodes can be understood in terms of the symmetry of surface and anion orbitals and by the change in the balance between solvation and bonding energies which can occur on electrodes of different bonding propensity