Corundum (structure)

Structure

The corundum structure has the space group R3c. 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.