Periclase Solid Solutions Containing Li+1 and R+3 Ions

Recent work on phase equilibria diagrams has shown that periclase can take R+3 (Cr+3, Al+3, and Fe+3) in solid solution at elevated temperatures. In order to retain electrical neutrality, 2R(+3) and a vacancy replaces 3Mg(+2) in the periclase lattices. When Li+1 is added to MgO/R2O3 compositions, one Li+1 and one R+3 replaces 2 Mg+2 to form a solid solution which is stable at room temperature. These periclase solid solutions are more stable under conditions of temperature fluctuations and hydration than periclase/R2O3 solid solutions without lithia.