Structure and Stability of βAlumina Type Phases

Polycrystalline β“alumina isomorphs have been produced by ion exchange of Na β“alumina in various molten salts or salt vapors. The exchanged samples were heated to determine their stable structure after thermal decomposition. The stable structures are classified according to the cation on the conduction plane. Cation size and charge are believed to be the critical factors determining the stable structure.