The Electrical Conductivity of Molten Lithium Sulphate with Small Quantities of Foreign Cations

Abstract

The electrical conductivity of molten lithium sulphate with small quantities of foreign cations (Na+, K+, Rb+, Cs+, Mn++, Cd++ and Ba++) has been measured from 700 to 950°C. The temperature dependence of the specific conductivity can in all cases with good accuracy be described by straight lines. The decrease in the specific conductivity is approximately proportional to the volume of the foreign cation. If it is assumed that the cations are moving in groups, the number of ions in each di group is found to be 2.7. The change in free volume of molten lithium sulphate, when a small quantity of foreign ions is added, seems to have little importance for the change in electrical conductivity. An estimation of the mobility of Cd++ ions indicates the existens of Wagner effect in molten lithium sulphate.