The material structure described by Al2O3 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to one O(2), two equivalent O(1), and two equivalent O(3) atoms to form AlO5 trigonal bipyramids that share corners with four equivalent Al(2)O4 tetrahedra,  an edgeedge with one Al(2)O4 tetrahedra, and edges with two equivalent Al(1)O5 trigonal bipyramids. In the second Al site, Al(2) is bonded to one O(1), one O(3), and two equivalent O(2) atoms to form AlO4 tetrahedra that share corners with two equivalent Al(2)O4 tetrahedra, corners with four equivalent Al(1)O5 trigonal bipyramids, and  an edgeedge with one Al(1)O5 trigonal bipyramid. There are three inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Al(2) and two equivalent Al(1) atoms. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Al(1) and two equivalent Al(2) atoms. In the third O site, O(3) is bonded in a distorted T-shaped geometry to one Al(2) and two equivalent Al(1) atoms. is represented by the CIF card [CIF]
data_Al2O3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.504
_cell_length_b   8.240
_cell_length_c   5.419
_cell_angle_alpha   90.000
_cell_angle_beta   58.597
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   209.767
_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  0.948  0.043  0.284  1.0
  Al  Al1  1  0.948  0.457  0.784  1.0
  Al  Al2  1  0.534  0.344  0.704  1.0
  Al  Al3  1  0.466  0.844  0.796  1.0
  Al  Al4  1  0.534  0.156  0.204  1.0
  Al  Al5  1  0.466  0.656  0.296  1.0
  Al  Al6  1  0.052  0.543  0.216  1.0
  Al  Al7  1  0.052  0.957  0.716  1.0
  O  O8  1  0.174  0.109  0.432  1.0
  O  O9  1  0.320  0.705  0.081  1.0
  O  O10  1  0.174  0.391  0.932  1.0
  O  O11  1  0.250  0.480  0.422  1.0
  O  O12  1  0.750  0.980  0.078  1.0
  O  O13  1  0.320  0.795  0.581  1.0
  O  O14  1  0.680  0.205  0.419  1.0
  O  O15  1  0.250  0.020  0.922  1.0
  O  O16  1  0.750  0.520  0.578  1.0
  O  O17  1  0.826  0.609  0.068  1.0
  O  O18  1  0.680  0.295  0.919  1.0
  O  O19  1  0.826  0.891  0.568  1.0
[/CIF]
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The material structure described by Al2O3 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to one O(2), two equivalent O(1), and two equivalent O(3) atoms to form AlO5 trigonal bipyramids that share corners with four equivalent Al(2)O4 tetrahedra,  an edgeedge with one Al(2)O4 tetrahedra, and edges with two equivalent Al(1)O5 trigonal bipyramids. In the second Al site, Al(2) is bonded to one O(1), one O(3), and two equivalent O(2) atoms to form AlO4 tetrahedra that share corners with two equivalent Al(2)O4 tetrahedra, corners with four equivalent Al(1)O5 trigonal bipyramids, and  an edgeedge with one Al(1)O5 trigonal bipyramid. There are three inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Al(2) and two equivalent Al(1) atoms. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Al(1) and two equivalent Al(2) atoms. In the third O site, O(3) is bonded in a distorted T-shaped geometry to one Al(2) and two equivalent Al(1) atoms. is represented by the CIF card [CIF]
data_Al2O3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.504
_cell_length_b   8.240
_cell_length_c   5.419
_cell_angle_alpha   90.000
_cell_angle_beta   58.597
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   209.767
_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  0.948  0.043  0.284  1.0
  Al  Al1  1  0.948  0.457  0.784  1.0
  Al  Al2  1  0.534  0.344  0.704  1.0
  Al  Al3  1  0.466  0.844  0.796  1.0
  Al  Al4  1  0.534  0.156  0.204  1.0
  Al  Al5  1  0.466  0.656  0.296  1.0
  Al  Al6  1  0.052  0.543  0.216  1.0
  Al  Al7  1  0.052  0.957  0.716  1.0
  O  O8  1  0.174  0.109  0.432  1.0
  O  O9  1  0.320  0.705  0.081  1.0
  O  O10  1  0.174  0.391  0.932  1.0
  O  O11  1  0.250  0.480  0.422  1.0
  O  O12  1  0.750  0.980  0.078  1.0
  O  O13  1  0.320  0.795  0.581  1.0
  O  O14  1  0.680  0.205  0.419  1.0
  O  O15  1  0.250  0.020  0.922  1.0
  O  O16  1  0.750  0.520  0.578  1.0
  O  O17  1  0.826  0.609  0.068  1.0
  O  O18  1  0.680  0.295  0.919  1.0
  O  O19  1  0.826  0.891  0.568  1.0
[/CIF]
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