Molten salts have been used for many centuries in metal extraction, glass manufacture, and, more recently, in applications such as fused salt electrolysis. Usually dissociated into ions, they are often good solvents for oxides, carbides, nitrides, and metals. Their high thermal stability, low vapor pressure, good thermal and electrical conductivity, and low viscosity may be expected to confer on them an increasing technological importance in the future, and as a result research on their physical and chemical properties has grown markedly in recent years. Thermodynamic and transport properties [l-41 have been surveyed within the last decade, and Sundermeyer [5] has also reviewed their use as reaction media. A selection of catalytic reactions has been discussed by Kenney [6].