Fused salt systems containing oxides have received the most attention to date, because of their occurrence in minerals and ores and their application to ceramics. The next most widely studied of group of compounds are the metal halides, particularly the metal chlorides. Despite the fact that many of the metal chlorides are hygroscopic, the salts lend themselves to experimentation because a large majority undergo stable solid-liquid transformations below 1000 degrees C, are generally ionic, and are relatively non-corrosive
