Materials Data on Al2O3 by Materials Project

Abstract

Al2O3 crystallizes in the triclinic P-1 space group. The structure is two-dimensional and consists of one Al2O3 sheet oriented in the (0, 0, 1) direction. there are two inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded in a trigonal non-coplanar geometry to three O2- atoms. There is one shorter (1.81 Å) and two longer (1.82 Å) Al–O bond length. In the second Al3+ site, Al3+ is bonded to five O2- atoms to form distorted edge-sharing AlO5 square pyramids. There are a spread of Al–O bond distances ranging from 1.80–1.93 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Al3+ and one O2- atom. The O–O bond length is 1.49 Å. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to three Al3+ atoms. In the third O2- site, O2- is bonded in a trigonal planar geometry to three Al3+ atoms.