Materials Data on Al2O3 by Materials Project

Al2O3 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. Al3+ is bonded to five O2- atoms to form a mixture of edge and corner-sharing AlO5 trigonal bipyramids. There are a spread of Al–O bond distances ranging from 1.78–2.02 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a T-shaped geometry to three equivalent Al3+ atoms. In the second O2- site, O2- is bonded in a see-saw-like geometry to four equivalent Al3+ atoms.

三氧化二铝（Al₂O₃）结晶于单斜晶系C2/c空间群，其结构为三维网状结构。三价铝离子（Al³⁺）与五个二价氧离子（O²⁻）形成配位键，构成以共享棱与共享角方式连接的AlO₅三角双锥混合结构单元。Al-O键的键长分布范围为1.78~2.02埃（Å）。体系中存在两类不等价的二价氧离子位点：在第一类氧离子位点中，O²⁻以T型配位几何与三个等价的Al³⁺原子配位；在第二类氧离子位点中，O²⁻以类跷跷板配位几何与四个等价的Al³⁺原子配位。