Protonic conductivity in layered SnCl2· 2H2O single crystal

Abstract

The electric conductivity of stannous chloride dihydrate single crystals, measured both with injecting and with metallic electrodes, shows two contributions: a critical, frequency dependent behaviour around the phase transition temperature and a temperature activated process, both in the disordered phase and in the ordered phase. This second process causes a very large conductivity which, along the c direction and at room temperature, results of the order of 10^–6Ω^–1 cm^–1. The conduction shows ohmic behaviour at low fields and non-ohmic behaviour at higher fields (space–charge–limited current). Arguments in favour of protonic conduction are given and a model is proposed to interpret the conduction mechanism.