Al2O3 crystallizes in the monoclinic C2/m space group. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to two equivalent O(1) and three equivalent O(2) atoms to form a mixture of distorted corner and edge-sharing AlO5 trigonal bipyramids. In the second Al site, Al(2) is bonded to one O(1), one O(2), and three equivalent O(3) atoms to form a mixture of corner and edge-sharing AlO5 trigonal bipyramids. There are three inequivalent O sites. In the first O site, O(1) is bonded in a T-shaped geometry to one Al(2) and two equivalent Al(1) atoms. In the second O site, O(2) is bonded to one Al(2) and three equivalent Al(1) atoms to form a mixture of distorted corner and edge-sharing OAl4 trigonal pyramids. In the third O site, O(3) is bonded in a T-shaped geometry to three equivalent Al(2) atoms.
Al2O3 crystallizes in the monoclinic C2/m space group. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to two equivalent O(1) and three equivalent O(2) atoms to form a mixture of distorted corner and edge-sharing AlO5 trigonal bipyramids. There is one shorter (1.79 Å) and one longer (1.83 Å) Al(1)-O(1) bond length. There are two shorter (1.81 Å) and one longer (2.13 Å) Al(1)-O(2) bond length. In the second Al site, Al(2) is bonded to one O(1), one O(2), and three equivalent O(3) atoms to form a mixture of corner and edge-sharing AlO5 trigonal bipyramids. The Al(2)-O(1) bond length is 1.77 Å. The Al(2)-O(2) bond length is 1.95 Å. There are two shorter (1.79 Å) and one longer (1.90 Å) Al(2)-O(3) bond length. There are three inequivalent O sites. In the first O site, O(1) is bonded in a T-shaped geometry to one Al(2) and two equivalent Al(1) atoms. In the second O site, O(2) is bonded to one Al(2) and three equivalent Al(1) atoms to form a mixture of distorted corner and edge-sharing OAl4 trigonal pyramids. In the third O site, O(3) is bonded in a T-shaped geometry to three equivalent Al(2) atoms.