Corundum is the name for a structure prototype in inorganic solids, derived from the namesake polymorph of aluminum oxide (α-Al2O3). Other compounds, especially among the inorganic solids, exist in corundum structure, either in ambient or other conditions. Corundum structures are associated with metal-insulator transition, ferroelectricity, polar magnetism, and magnetoelectric effects.
Structure The corundum structure has the space group . It typically exists in binary compounds of the type A2B3, where A is metallic and B is nonmetallic, including sesquioxides (A2O3), sesquisulfides (A2S3), etc. When A is nonmetallic and B is metallic, the structure becomes the antiphase of corundum, called the anticorundum structure type, with examples including β-Ca3N2 and borates. Ternary and multinary compounds can also exists in the corundum structure. The corundum-like structure with the composition A2BB'O6 is called double corundum. A list of examples are tabulated below.
+ Materials that exist in the corundum structure Chemical formula Alternative name Material type Reference Al2O3 α-Al2O3 or corundum Oxide V2O3 Oxide Cr2O3 α-Cr2O3 Oxide Fe2O3 α-Fe2O3 or hematite Oxide Ga2O3 α-Ga2O3 Oxide In2O3 rh-In2O3 Oxide Ti2O3 α-Ti2O3 Oxide Mn2O3 ε-Mn2O3 Oxide Rh2O3 Oxide Ir2O3 α-Ir2O3 Oxide Tl2O3 Oxide Ca3N2 β-Ca3N2 Nitride In2S3 ε-In2S3 Sulfide Tm2S3 E-Tm2S3 or ε-Tm2S3 Sulfide Yb2S3 E-Yb2S3 or ε-Yb2S3 Sulfide Lu2S3 E-Lu2S3 or ε-Lu2S3 Sulfide Cr2(CN2)3 Carbodiimide Yb2(CN2)3 Carbodiimide Ca3(BO3)2 Borate Sr3(BO3)2 Borate Eu3(BO3)2 Borate ScFeO3 Ferrite GaFeO3 Ferrite InFeO3 Ferrite CrTiO3 Titanate NiCrO3 Chromite InVO3 Vanadate Ni3TeO6 Double oxide Ni2InSbO6 Double oxide Ni2ScSbO6 Double oxide Mn2FeMoO6 Double oxide Mn2FeWO6 Double oxide Co4Ta2O9 Triple oxide
See also Corundum Ilmenite Perovskite (structure)
References