Direct Synthesis of Powdery Inorganic Electride [Ca24Al28O64]4+(e−)4 and Determination of Oxygen Stoichiometry

We found a method for direct synthesis of C12A7 electride [Ca24Al28O64]4+(e−)4 powders from Ca12Al14O33 (C12A7), CaAl2O4 (CA), and Ca metal; C12A7 and CA were synthesized from CaCO3 and Al2O3. The chemical composition of the powders agrees with that of C12A7 lacking the encaged O2− ions, and the electron concentration was almost equal to the theoretical value of positive charge density of C12A7 cage skeleton.