Effect of pressure on the electrical conductivity of the molten dichlorides, bromides and iodides of cadmium, tin and lead

Abstract

The electrical conductivities of the molten dichlorides, bromides and iodides of cadmium, tin and lead have been measured as a function of pressure, at a series of temperatures up to 170 K above the respective melting points. For the cadmium halides, the conductivity increases with pressure at all temperatures, whereas the conductivity of the tin and lead halides decreases with pressure. The increase observed for the cadmium halides is attributed to an increase in the concentration of metal ions and halide ions caused by dissociation of complex ions or molecules present in the melts at low pressure. For the tin and lead halides, a reduction of ionic mobility with pressure dominates the overall effect of pressure on the conductivity; dissociation of complex ions may also be involved in the case of lead iodide, but is thought to play a relatively minor role for the remaining compounds.