The material described by Al2O3 is Corundum-like structured and crystallizes in the trigonal P-31c space group. There are three inequivalent Al sites. In the first Al site, Al(1) is bonded to six equivalent O(1) atoms to form a mixture of distorted corner, face, and edge-sharing AlO6 octahedra. The corner-sharing octahedral tilt angles are 53°. In the second Al site, Al(2) is bonded to six equivalent O(1) atoms to form a mixture of corner and face-sharing AlO6 octahedra. The corner-sharing octahedral tilt angles range from 44-53°. In the third Al site, Al(3) is bonded to six equivalent O(1) atoms to form a mixture of corner and edge-sharing AlO6 octahedra. The corner-sharing octahedral tilt angles are 44°. O(1) is bonded to one Al(2), one Al(3), and two equivalent Al(1) atoms to form a mixture of corner and edge-sharing OAl4 trigonal pyramids. is represented by the CIF card [CIF]
data_Al2O3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.793
_cell_length_b   4.793
_cell_length_c   8.967
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   178.396
_cell_formula_units_Z   4
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
loop_
 _atom_site_type_symbol
 _atom_site_label
 _atom_site_symmetry_multiplicity
 _atom_site_fract_x
 _atom_site_fract_y
 _atom_site_fract_z
 _atom_site_occupancy
  Al  Al0  1  0.333  0.667  0.963  1.0
  Al  Al1  1  0.333  0.667  0.250  1.0
  Al  Al2  1  1.000  1.000  1.000  1.0
  Al  Al3  1  1.000  0.000  0.500  1.0
  Al  Al4  1  0.333  0.667  0.537  1.0
  Al  Al5  1  0.667  0.333  0.037  1.0
  Al  Al6  1  0.667  0.333  0.750  1.0
  Al  Al7  1  0.667  0.333  0.463  1.0
  O  O8  1  0.032  0.677  0.112  1.0
  O  O9  1  0.968  0.645  0.612  1.0
  O  O10  1  0.032  0.355  0.388  1.0
  O  O11  1  0.968  0.323  0.888  1.0
  O  O12  1  0.323  0.355  0.112  1.0
  O  O13  1  0.355  0.323  0.612  1.0
  O  O14  1  0.323  0.968  0.388  1.0
  O  O15  1  0.355  0.032  0.888  1.0
  O  O16  1  0.645  0.677  0.388  1.0
  O  O17  1  0.677  0.645  0.888  1.0
  O  O18  1  0.645  0.968  0.112  1.0
  O  O19  1  0.677  0.032  0.612  1.0
[/CIF]
.
The material described by Al2O3 is Corundum-like structured and crystallizes in the trigonal P-31c space group. There are three inequivalent Al sites. In the first Al site, Al(1) is bonded to six equivalent O(1) atoms to form a mixture of distorted corner, face, and edge-sharing AlO6 octahedra. The corner-sharing octahedral tilt angles are 53°. In the second Al site, Al(2) is bonded to six equivalent O(1) atoms to form a mixture of corner and face-sharing AlO6 octahedra. The corner-sharing octahedral tilt angles range from 44-53°. In the third Al site, Al(3) is bonded to six equivalent O(1) atoms to form a mixture of corner and edge-sharing AlO6 octahedra. The corner-sharing octahedral tilt angles are 44°. O(1) is bonded to one Al(2), one Al(3), and two equivalent Al(1) atoms to form a mixture of corner and edge-sharing OAl4 trigonal pyramids. is represented by the CIF card [CIF]
data_Al2O3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.793
_cell_length_b   4.793
_cell_length_c   8.967
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   178.396
_cell_formula_units_Z   4
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
loop_
 _atom_site_type_symbol
 _atom_site_label
 _atom_site_symmetry_multiplicity
 _atom_site_fract_x
 _atom_site_fract_y
 _atom_site_fract_z
 _atom_site_occupancy
  Al  Al0  1  0.333  0.667  0.963  1.0
  Al  Al1  1  0.333  0.667  0.250  1.0
  Al  Al2  1  1.000  1.000  1.000  1.0
  Al  Al3  1  1.000  0.000  0.500  1.0
  Al  Al4  1  0.333  0.667  0.537  1.0
  Al  Al5  1  0.667  0.333  0.037  1.0
  Al  Al6  1  0.667  0.333  0.750  1.0
  Al  Al7  1  0.667  0.333  0.463  1.0
  O  O8  1  0.032  0.677  0.112  1.0
  O  O9  1  0.968  0.645  0.612  1.0
  O  O10  1  0.032  0.355  0.388  1.0
  O  O11  1  0.968  0.323  0.888  1.0
  O  O12  1  0.323  0.355  0.112  1.0
  O  O13  1  0.355  0.323  0.612  1.0
  O  O14  1  0.323  0.968  0.388  1.0
  O  O15  1  0.355  0.032  0.888  1.0
  O  O16  1  0.645  0.677  0.388  1.0
  O  O17  1  0.677  0.645  0.888  1.0
  O  O18  1  0.645  0.968  0.112  1.0
  O  O19  1  0.677  0.032  0.612  1.0
[/CIF]
.