Corundum is the name for a structure prototype in inorganic solids, derived from the namesake polymorph of aluminum oxide (ñ-Al<sub>2</sub>O<sub>3</sub>). 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.
The corundum structure has the space group . It typically exists in binary compounds of the type A<sub>2</sub>B<sub>3</sub>, where A is metallic and B is nonmetallic, including sesquioxides (A<sub>2</sub>O<sub>3</sub>), sesquisulfides (A<sub>2</sub>S<sub>3</sub>), etc. When A is nonmetallic and B is metallic, the structure becomes the antiphase of corundum, called the anticorundum structure type, with examples including ò-Ca<sub>3</sub>N<sub>2</sub> and borates. Ternary and multinary compounds can also exists in the corundum structure. The corundum-like structure with the composition A<sub>2</sub>BB'O<sub>6</sub> is called double corundum. A list of examples are tabulated below.