Ionic Conductivity of Lead Chloride Crystals

Abstract

The ionic conductivity of single crystals of pure and KCl- and NaCl-doped PbCl₂ has been measured between 90 and 400°C. The thermal disorder appears to be of unassociated Schottky defects. The expressions for the “mobility” μ and the “concentration” x_n⁰ of anion vacancies have been determined from a comparison between the observed isothermals and those predicted from the simple theory of Koch and Wagner in which association effects are omitted. The experimental expressions are
μ=(2.6×10⁻¹⁄T)exp(−0.20±0.03⁄kT) cm² volt⁻¹ sec⁻¹
and x_n⁰=2.7×10²exp(−0.51±0.05⁄kT) in mole fraction, where kT is expressed in electron-volt. These are the first results, expressed as a function of temperature, for anion vacancies in PbCl₂ crystals.