Al2O3 is Corundum-like structured and crystallizes in the orthorhombic Pbca space group. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to one O(1), two equivalent O(3), and three equivalent O(2) atoms to form a mixture of face, corner, and edge-sharing AlO6 octahedra. The corner-sharing octahedral tilt angles range from 47-61°. In the second Al site, Al(2) is bonded to one O(2), two equivalent O(3), and three equivalent O(1) atoms to form a mixture of face, corner, and edge-sharing AlO6 octahedra. The corner-sharing octahedral tilt angles range from 48-70°. There are three inequivalent O sites. In the first O site, O(1) is bonded to one Al(1) and three equivalent Al(2) atoms to form a mixture of distorted corner and edge-sharing OAl4 tetrahedra. 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 to two equivalent Al(1) and two equivalent Al(2) atoms to form a mixture of distorted corner and edge-sharing OAl4 trigonal pyramids.
Al2O3 is Corundum-like structured and crystallizes in the orthorhombic Pbca space group. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to one O(1), two equivalent O(3), and three equivalent O(2) atoms to form a mixture of face, corner, and edge-sharing AlO6 octahedra. The corner-sharing octahedral tilt angles range from 47-61°. The Al(1)-O(1) bond length is 1.97 Å. There is one shorter (1.83 Å) and one longer (1.95 Å) Al(1)-O(3) bond length. There are a spread of Al(1)-O(2) bond distances ranging from 1.85-1.93 Å. In the second Al site, Al(2) is bonded to one O(2), two equivalent O(3), and three equivalent O(1) atoms to form a mixture of face, corner, and edge-sharing AlO6 octahedra. The corner-sharing octahedral tilt angles range from 48-70°. The Al(2)-O(2) bond length is 1.99 Å. There is one shorter (1.87 Å) and one longer (1.96 Å) Al(2)-O(3) bond length. There are a spread of Al(2)-O(1) bond distances ranging from 1.87-2.02 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded to one Al(1) and three equivalent Al(2) atoms to form a mixture of distorted corner and edge-sharing OAl4 tetrahedra. 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 to two equivalent Al(1) and two equivalent Al(2) atoms to form a mixture of distorted corner and edge-sharing OAl4 trigonal pyramids.