The material structure described by Al2O3 crystallizes in the monoclinic P2_1/m space group. There are six inequivalent Al sites. In the first Al site, Al(1) is bonded to one O(4), two equivalent O(1), and three equivalent O(3) atoms to form a mixture of corner and edge-sharing AlO6 octahedra. The corner-sharing octahedral tilt angles are 19°. In the second Al site, Al(2) is bonded in a 4-coordinate geometry to one O(4), two equivalent O(2), and three equivalent O(1) atoms. In the third Al site, Al(3) is bonded to one O(3), one O(7), two equivalent O(4), and two equivalent O(6) atoms to form a mixture of corner and edge-sharing AlO6 octahedra. The corner-sharing octahedral tilt angles range from 19-52°. In the fourth Al site, Al(4) is bonded in a 6-coordinate geometry to one O(2), one O(8), two equivalent O(5), and two equivalent O(6) atoms. In the fifth Al site, Al(5) is bonded to one O(5), two equivalent O(7), and three equivalent O(9) atoms to form a mixture of corner and edge-sharing AlO6 octahedra. The corner-sharing octahedral tilt angles are 52°. In the sixth Al site, Al(6) is bonded in a 6-coordinate geometry to one O(6), one O(9), two equivalent O(7), and two equivalent O(8) atoms. There are nine inequivalent O sites. In the first O site, O(1) is bonded in a 5-coordinate geometry to two equivalent Al(1) and three equivalent Al(2) atoms. In the second O site, O(2) is bonded in a trigonal planar geometry to one Al(4) and two equivalent Al(2) atoms. In the third O site, O(3) is bonded to one Al(3) and three equivalent Al(1) atoms to form a mixture of corner and edge-sharing OAl4 trigonal pyramids. In the fourth O site, O(4) is bonded to one Al(1), one Al(2), and two equivalent Al(3) atoms to form a mixture of corner and edge-sharing OAl4 trigonal pyramids. In the fifth O site, O(5) is bonded in a trigonal planar geometry to one Al(5) and two equivalent Al(4) atoms. In the sixth O site, O(6) is bonded in a 5-coordinate geometry to one Al(6), two equivalent Al(3), and two equivalent Al(4) atoms. In the seventh O site, O(7) is bonded in a 5-coordinate geometry to one Al(3), two equivalent Al(5), and two equivalent Al(6) atoms. In the eighth O site, O(8) is bonded in a trigonal non-coplanar geometry to one Al(4) and two equivalent Al(6) atoms. In the ninth O site, O(9) is bonded to one Al(6) and three equivalent Al(5) atoms to form a mixture of corner and edge-sharing OAl4 trigonal pyramids. is represented by the Crystallographic Information File (CIF) [CIF]
data_Al2O3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   2.914
_cell_length_b   7.114
_cell_length_c   13.842
_cell_angle_alpha   77.122
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   279.726
_cell_formula_units_Z   6
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  0.250  0.826  0.028  1.0
  Al  Al1  1  0.250  0.438  0.113  1.0
  Al  Al2  1  0.750  0.802  0.213  1.0
  Al  Al3  1  0.750  0.187  0.298  1.0
  Al  Al4  1  0.250  0.467  0.412  1.0
  Al  Al5  1  0.250  0.849  0.398  1.0
  Al  Al6  1  0.750  0.151  0.602  1.0
  Al  Al7  1  0.750  0.533  0.588  1.0
  Al  Al8  1  0.250  0.813  0.702  1.0
  Al  Al9  1  0.250  0.198  0.787  1.0
  Al  Al10  1  0.750  0.562  0.887  1.0
  Al  Al11  1  0.750  0.174  0.972  1.0
  O  O12  1  0.750  0.658  0.002  1.0
  O  O13  1  0.750  0.315  0.168  1.0
  O  O14  1  0.750  0.959  0.078  1.0
  O  O15  1  0.250  0.667  0.160  1.0
  O  O16  1  0.250  0.305  0.330  1.0
  O  O17  1  0.250  0.945  0.257  1.0
  O  O18  1  0.750  0.642  0.345  1.0
  O  O19  1  0.750  0.987  0.407  1.0
  O  O20  1  0.750  0.354  0.496  1.0
  O  O21  1  0.250  0.646  0.504  1.0
  O  O22  1  0.250  0.013  0.593  1.0
  O  O23  1  0.250  0.358  0.655  1.0
  O  O24  1  0.750  0.055  0.743  1.0
  O  O25  1  0.750  0.695  0.670  1.0
  O  O26  1  0.750  0.333  0.840  1.0
  O  O27  1  0.250  0.041  0.922  1.0
  O  O28  1  0.250  0.685  0.832  1.0
  O  O29  1  0.250  0.342  0.998  1.0
[/CIF]
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The material structure described by Al2O3 crystallizes in the monoclinic P2_1/m space group. There are six inequivalent Al sites. In the first Al site, Al(1) is bonded to one O(4), two equivalent O(1), and three equivalent O(3) atoms to form a mixture of corner and edge-sharing AlO6 octahedra. The corner-sharing octahedral tilt angles are 19°. In the second Al site, Al(2) is bonded in a 4-coordinate geometry to one O(4), two equivalent O(2), and three equivalent O(1) atoms. In the third Al site, Al(3) is bonded to one O(3), one O(7), two equivalent O(4), and two equivalent O(6) atoms to form a mixture of corner and edge-sharing AlO6 octahedra. The corner-sharing octahedral tilt angles range from 19-52°. In the fourth Al site, Al(4) is bonded in a 6-coordinate geometry to one O(2), one O(8), two equivalent O(5), and two equivalent O(6) atoms. In the fifth Al site, Al(5) is bonded to one O(5), two equivalent O(7), and three equivalent O(9) atoms to form a mixture of corner and edge-sharing AlO6 octahedra. The corner-sharing octahedral tilt angles are 52°. In the sixth Al site, Al(6) is bonded in a 6-coordinate geometry to one O(6), one O(9), two equivalent O(7), and two equivalent O(8) atoms. There are nine inequivalent O sites. In the first O site, O(1) is bonded in a 5-coordinate geometry to two equivalent Al(1) and three equivalent Al(2) atoms. In the second O site, O(2) is bonded in a trigonal planar geometry to one Al(4) and two equivalent Al(2) atoms. In the third O site, O(3) is bonded to one Al(3) and three equivalent Al(1) atoms to form a mixture of corner and edge-sharing OAl4 trigonal pyramids. In the fourth O site, O(4) is bonded to one Al(1), one Al(2), and two equivalent Al(3) atoms to form a mixture of corner and edge-sharing OAl4 trigonal pyramids. In the fifth O site, O(5) is bonded in a trigonal planar geometry to one Al(5) and two equivalent Al(4) atoms. In the sixth O site, O(6) is bonded in a 5-coordinate geometry to one Al(6), two equivalent Al(3), and two equivalent Al(4) atoms. In the seventh O site, O(7) is bonded in a 5-coordinate geometry to one Al(3), two equivalent Al(5), and two equivalent Al(6) atoms. In the eighth O site, O(8) is bonded in a trigonal non-coplanar geometry to one Al(4) and two equivalent Al(6) atoms. In the ninth O site, O(9) is bonded to one Al(6) and three equivalent Al(5) atoms to form a mixture of corner and edge-sharing OAl4 trigonal pyramids. is represented by the Crystallographic Information File (CIF) [CIF]
data_Al2O3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   2.914
_cell_length_b   7.114
_cell_length_c   13.842
_cell_angle_alpha   77.122
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   279.726
_cell_formula_units_Z   6
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  0.250  0.826  0.028  1.0
  Al  Al1  1  0.250  0.438  0.113  1.0
  Al  Al2  1  0.750  0.802  0.213  1.0
  Al  Al3  1  0.750  0.187  0.298  1.0
  Al  Al4  1  0.250  0.467  0.412  1.0
  Al  Al5  1  0.250  0.849  0.398  1.0
  Al  Al6  1  0.750  0.151  0.602  1.0
  Al  Al7  1  0.750  0.533  0.588  1.0
  Al  Al8  1  0.250  0.813  0.702  1.0
  Al  Al9  1  0.250  0.198  0.787  1.0
  Al  Al10  1  0.750  0.562  0.887  1.0
  Al  Al11  1  0.750  0.174  0.972  1.0
  O  O12  1  0.750  0.658  0.002  1.0
  O  O13  1  0.750  0.315  0.168  1.0
  O  O14  1  0.750  0.959  0.078  1.0
  O  O15  1  0.250  0.667  0.160  1.0
  O  O16  1  0.250  0.305  0.330  1.0
  O  O17  1  0.250  0.945  0.257  1.0
  O  O18  1  0.750  0.642  0.345  1.0
  O  O19  1  0.750  0.987  0.407  1.0
  O  O20  1  0.750  0.354  0.496  1.0
  O  O21  1  0.250  0.646  0.504  1.0
  O  O22  1  0.250  0.013  0.593  1.0
  O  O23  1  0.250  0.358  0.655  1.0
  O  O24  1  0.750  0.055  0.743  1.0
  O  O25  1  0.750  0.695  0.670  1.0
  O  O26  1  0.750  0.333  0.840  1.0
  O  O27  1  0.250  0.041  0.922  1.0
  O  O28  1  0.250  0.685  0.832  1.0
  O  O29  1  0.250  0.342  0.998  1.0
[/CIF]
.