Materials Data on Al2O3 by Materials Project

Abstract

Al2O3 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are twelve inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded in a trigonal planar geometry to three O2- atoms. There is two shorter (1.69 Å) and one longer (1.70 Å) Al–O bond length. In the second Al3+ site, Al3+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of Al–O bond distances ranging from 1.68–1.70 Å. In the third Al3+ site, Al3+ is bonded to five O2- atoms to form AlO5 trigonal bipyramids that share a cornercorner with one AlO4 tetrahedra, corners with two equivalent AlO4 trigonal pyramids, an edgeedge with one AlO4 tetrahedra, and edges with two equivalent AlO5 trigonal bipyramids. There are a spread of Al–O bond distances ranging from 1.76–1.97 Å. In the fourth Al3+ site, Al3+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of Al–O bond distances ranging from 1.68–1.70 Å. In the fifth Al3+ site, Al3+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of Al–O bond distances ranging from 1.67–1.73 Å. In the sixth Al3+ site, Al3+ is bonded to four O2- atoms to form a mixture of distorted edge and corner-sharing AlO4 tetrahedra. There are a spread of Al–O bond distances ranging from 1.74–1.84 Å. In the seventh Al3+ site, Al3+ is bonded to five O2- atoms to form a mixture of distorted edge and corner-sharing AlO5 trigonal bipyramids. There are a spread of Al–O bond distances ranging from 1.79–2.02 Å. In the eighth Al3+ site, Al3+ is bonded to five O2- atoms to form distorted AlO5 trigonal bipyramids that share corners with two equivalent AlO4 tetrahedra, corners with two AlO4 trigonal pyramids, edges with two equivalent AlO5 trigonal bipyramids, and an edgeedge with one AlO4 trigonal pyramid. There are a spread of Al–O bond distances ranging from 1.77–2.03 Å. In the ninth Al3+ site, Al3+ is bonded to four O2- atoms to form distorted AlO4 trigonal pyramids that share corners with four AlO5 trigonal bipyramids, corners with two equivalent AlO4 trigonal pyramids, and an edgeedge with one AlO5 trigonal bipyramid. There is three shorter (1.78 Å) and one longer (1.85 Å) Al–O bond length. In the tenth Al3+ site, Al3+ is bonded to four O2- atoms to form distorted AlO4 trigonal pyramids that share corners with two AlO5 trigonal bipyramids, corners with two equivalent AlO4 trigonal pyramids, and an edgeedge with one AlO5 trigonal bipyramid. There are a spread of Al–O bond distances ranging from 1.75–1.85 Å. In the eleventh Al3+ site, Al3+ is bonded in a distorted see-saw-like geometry to four O2- atoms. There are a spread of Al–O bond distances ranging from 1.76–1.83 Å. In the twelfth Al3+ site, Al3+ is bonded to four O2- atoms to form corner-sharing AlO4 tetrahedra. There are a spread of Al–O bond distances ranging from 1.72–1.79 Å. There are eighteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 120 degrees geometry to two Al3+ atoms. In the second O2- site, O2- is bonded in a bent 150 degrees geometry to two Al3+ atoms. In the third O2- site, O2- is bonded in a bent 150 degrees geometry to two Al3+ atoms. In the fourth O2- site, O2- is bonded in a bent 150 degrees geometry to two Al3+ atoms. In the fifth O2- site, O2- is bonded in a distorted trigonal planar geometry to three Al3+ atoms. In the sixth O2- site, O2- is bonded in a bent 120 degrees geometry to two Al3+ atoms. In the seventh O2- site, O2- is bonded in a distorted trigonal planar geometry to three Al3+ atoms. In the eighth O2- site, O2- is bonded in a T-shaped geometry to three Al3+ atoms. In the ninth O2- site, O2- is bonded in a T-shaped geometry to three Al3+ atoms. In the tenth O2- site, O2- is bonded in a distorted trigonal planar geometry to three Al3+ atoms. In the eleventh O2- site, O2- is bonded in a distorted trigonal planar geometry to three Al3+ atoms. In the twelfth O2- site, O2- is bonded in a distorted trigonal planar geometry to three Al3+ atoms. In the thirteenth O2- site, O2- is bonded in a distorted trigonal planar geometry to three Al3+ atoms. In the fourteenth O2- site, O2- is bonded in a T-shaped geometry to three Al3+ atoms. In the fifteenth O2- site, O2- is bonded in a distorted T-shaped geometry to three Al3+ atoms. In the sixteenth O2- site, O2- is bonded in a bent 150 degrees geometry to two Al3+ atoms. In the seventeenth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to three Al3+ atoms. In the eighteenth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two Al3+ atoms.