p-d hybridization of noble metal halides

The eletronic band calculations of noble metal halides are studied to make the high ionic conducting origin of silver and cupper ions clear using the tight-binding method. The d bands of Ag ions are much more weakly coupled with the p bands of halogen ions, while those of Cu ions are much more strongly coupled with the p bands. The strength of p-d hybridization is discussed to connect with the activation energy for the ionic conduction. It is shown that the high ionic conductivity of AgX primary stems from combination of the deformability of the d shell and the weakness of the p-d hybridization.