Electrode Behavior and the Determination of Defect Energies from Measurements of Ionic Conductivity in NaCl Crystals

Reported values given by different observers for the enthalpy of cation vacancy migration in alkali halides show a much greater spread than might be expected from the quoted instrumental accuracies. The customary types of electrodes used in this kind of investigation have therefore been examined in terms of durability and the repeatability and linearity of the results obtained using them. A type of electrode is described which gives superior performance in these respects to that usually reported. A careful determination of defect energies from ionic conductivity measurements in NaCl was undertaken using this electrode arrangement, and the results are compared with those quoted by other investigators.