Structure property relationships and cationic doping in [Ca24Al28O64]4+ framework: A review

Abstract

Ca12Al14O33 (C12A7, 12CaO·7Al2O3, or [Ca12Al14O32]2+:O2–) is a material with a clathrate cage framework, positively charged and stabilized by anions occluded within 17% of the cages. The occluded anion is modular and can be elemental, polyatomic, and electronic in nature. This review focuses on the electride C12A7 ([Ca24Al28O64]4+:(4 *∂) e–(2 ∂)O2–), where O2– anions are replaced with electrons, and compliments previous structural and electronic property reviews to illuminate the structure–property relationships. Electride formation is updated with new findings in carbonaceous reduction methods. Most importantly, an extensive compilation of cationic doped C12A7 isostructural compounds is presented as motivation to study doped C12A7 electrides. Cationic dopants have profound impacts on the electronic properties due to changes in the density of states, localized electron behavior, and structural distortions.