Reactivity and catalytic activity of copper chlorides. Part 4.—Electrical properties and acceptor levels produced in CuCl by Cl2 gas

Abstract

Studies of electrical conductivity, thermoelectric power and transport numbers in CuCl, pure or after exposure to Cl2 gas, in the range 24–240°C, have shown that all phenomena observed are caused by electronic rather than ionic conduction, except in pure CuCl above about 140°C. Two acceptor levels are identified, at 0.51 and 0.88 eV above the valence band. The former is attributed to cation vacancies; the latter, tentatively, to anion interstitials. For high concentrations of cation vacancies, the conduction below 100°C is predominantly by electrons in a narrow band at the acceptor level, the activation energy of this “hopping” process being 0.36 eV. The difference between the two acceptor levels is briefly discussed in terms of ligand field splitting of the Cu 3d orbitals.