The crystal structure described by Al2O3 crystallizes in the trigonal R3m space group. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to three equivalent O(2) and three equivalent O(3) atoms to form AlO6 octahedra that share corners with six equivalent Al(2)O5 trigonal bipyramids and edges with six equivalent Al(1)O6 octahedra. In the second Al site, Al(2) is bonded to one O(2), one O(3), and three equivalent O(1) atoms to form AlO5 trigonal bipyramids that share corners with six equivalent Al(1)O6 octahedra and corners with six equivalent Al(2)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 61-62°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to three equivalent Al(2) 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 edge and corner-sharing OAl4 tetrahedra. In the third O site, O(3) is bonded to one Al(2) and three equivalent Al(1) atoms to form a mixture of edge and corner-sharing OAl4 tetrahedra. is represented by the Crystallographic Information File (CIF) [CIF]
data_Al2O3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.002
_cell_length_b   6.021
_cell_length_c   3.002
_cell_angle_alpha   104.433
_cell_angle_beta   60.000
_cell_angle_gamma   104.433
_symmetry_Int_Tables_number   1
_cell_volume   44.998
_cell_formula_units_Z   1
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  0.193  0.579  0.193  1.0
  Al  Al1  1  0.693  0.080  0.693  1.0
  O  O2  1  0.028  0.085  0.028  1.0
  O  O3  1  0.582  0.746  0.582  1.0
  O  O4  1  0.807  0.420  0.807  1.0
[/CIF]
.
The crystal structure described by Al2O3 crystallizes in the trigonal R3m space group. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to three equivalent O(2) and three equivalent O(3) atoms to form AlO6 octahedra that share corners with six equivalent Al(2)O5 trigonal bipyramids and edges with six equivalent Al(1)O6 octahedra. In the second Al site, Al(2) is bonded to one O(2), one O(3), and three equivalent O(1) atoms to form AlO5 trigonal bipyramids that share corners with six equivalent Al(1)O6 octahedra and corners with six equivalent Al(2)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 61-62°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to three equivalent Al(2) 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 edge and corner-sharing OAl4 tetrahedra. In the third O site, O(3) is bonded to one Al(2) and three equivalent Al(1) atoms to form a mixture of edge and corner-sharing OAl4 tetrahedra. is represented by the Crystallographic Information File (CIF) [CIF]
data_Al2O3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.002
_cell_length_b   6.021
_cell_length_c   3.002
_cell_angle_alpha   104.433
_cell_angle_beta   60.000
_cell_angle_gamma   104.433
_symmetry_Int_Tables_number   1
_cell_volume   44.998
_cell_formula_units_Z   1
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  0.193  0.579  0.193  1.0
  Al  Al1  1  0.693  0.080  0.693  1.0
  O  O2  1  0.028  0.085  0.028  1.0
  O  O3  1  0.582  0.746  0.582  1.0
  O  O4  1  0.807  0.420  0.807  1.0
[/CIF]
.