The material described by CrAlO3 crystallizes in the hexagonal P6_3cm space group. Cr(1) is bonded to one O(2), one O(3), one O(4), and two equivalent O(1) atoms to form CrO5 trigonal bipyramids that share corners with four equivalent Al(1)O6 octahedra and corners with six equivalent Cr(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 61-67°. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to three equivalent O(3) and three equivalent O(4) atoms to form distorted AlO6 octahedra that share corners with six equivalent Cr(1)O5 trigonal bipyramids and edges with three equivalent Al(1)O6 octahedra. In the second Al site, Al(2) is bonded in a 6-coordinate geometry to three equivalent O(3) and three equivalent O(4) atoms. There are four inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to three equivalent Cr(1) atoms. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to three equivalent Cr(1) atoms. In the third O site, O(3) is bonded to one Cr(1), one Al(2), and two equivalent Al(1) atoms to form a mixture of edge and corner-sharing OAl3Cr tetrahedra. In the fourth O site, O(4) is bonded to one Cr(1), one Al(2), and two equivalent Al(1) atoms to form a mixture of edge and corner-sharing OAl3Cr tetrahedra. is represented by the CIF card [CIF]
data_AlCrO3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.516
_cell_length_b   5.516
_cell_length_c   11.631
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   306.475
_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  0.667  0.333  0.249  1.0
  Al  Al1  1  0.333  0.667  0.749  1.0
  Al  Al2  1  0.667  0.333  0.749  1.0
  Al  Al3  1  0.333  0.667  0.249  1.0
  Al  Al4  1  0.000  0.000  0.754  1.0
  Al  Al5  1  0.000  0.000  0.254  1.0
  Cr  Cr6  1  0.669  0.000  0.501  1.0
  Cr  Cr7  1  0.669  0.669  0.001  1.0
  Cr  Cr8  1  0.000  0.331  0.001  1.0
  Cr  Cr9  1  0.000  0.669  0.501  1.0
  Cr  Cr10  1  0.331  0.331  0.501  1.0
  Cr  Cr11  1  0.331  0.000  0.001  1.0
  O  O12  1  0.667  0.333  0.019  1.0
  O  O13  1  0.333  0.667  0.519  1.0
  O  O14  1  0.667  0.333  0.519  1.0
  O  O15  1  0.333  0.667  0.019  1.0
  O  O16  1  0.000  0.000  0.971  1.0
  O  O17  1  0.000  0.000  0.471  1.0
  O  O18  1  0.355  0.000  0.828  1.0
  O  O19  1  0.355  0.355  0.328  1.0
  O  O20  1  0.000  0.645  0.328  1.0
  O  O21  1  0.000  0.355  0.828  1.0
  O  O22  1  0.645  0.645  0.828  1.0
  O  O23  1  0.645  0.000  0.328  1.0
  O  O24  1  0.314  0.000  0.175  1.0
  O  O25  1  0.314  0.314  0.675  1.0
  O  O26  1  0.000  0.686  0.675  1.0
  O  O27  1  0.000  0.314  0.175  1.0
  O  O28  1  0.686  0.686  0.175  1.0
  O  O29  1  0.686  0.000  0.675  1.0
[/CIF]
.
The material described by CrAlO3 crystallizes in the hexagonal P6_3cm space group. Cr(1) is bonded to one O(2), one O(3), one O(4), and two equivalent O(1) atoms to form CrO5 trigonal bipyramids that share corners with four equivalent Al(1)O6 octahedra and corners with six equivalent Cr(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 61-67°. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to three equivalent O(3) and three equivalent O(4) atoms to form distorted AlO6 octahedra that share corners with six equivalent Cr(1)O5 trigonal bipyramids and edges with three equivalent Al(1)O6 octahedra. In the second Al site, Al(2) is bonded in a 6-coordinate geometry to three equivalent O(3) and three equivalent O(4) atoms. There are four inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to three equivalent Cr(1) atoms. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to three equivalent Cr(1) atoms. In the third O site, O(3) is bonded to one Cr(1), one Al(2), and two equivalent Al(1) atoms to form a mixture of edge and corner-sharing OAl3Cr tetrahedra. In the fourth O site, O(4) is bonded to one Cr(1), one Al(2), and two equivalent Al(1) atoms to form a mixture of edge and corner-sharing OAl3Cr tetrahedra. is represented by the CIF card [CIF]
data_AlCrO3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.516
_cell_length_b   5.516
_cell_length_c   11.631
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   306.475
_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  0.667  0.333  0.249  1.0
  Al  Al1  1  0.333  0.667  0.749  1.0
  Al  Al2  1  0.667  0.333  0.749  1.0
  Al  Al3  1  0.333  0.667  0.249  1.0
  Al  Al4  1  0.000  0.000  0.754  1.0
  Al  Al5  1  0.000  0.000  0.254  1.0
  Cr  Cr6  1  0.669  0.000  0.501  1.0
  Cr  Cr7  1  0.669  0.669  0.001  1.0
  Cr  Cr8  1  0.000  0.331  0.001  1.0
  Cr  Cr9  1  0.000  0.669  0.501  1.0
  Cr  Cr10  1  0.331  0.331  0.501  1.0
  Cr  Cr11  1  0.331  0.000  0.001  1.0
  O  O12  1  0.667  0.333  0.019  1.0
  O  O13  1  0.333  0.667  0.519  1.0
  O  O14  1  0.667  0.333  0.519  1.0
  O  O15  1  0.333  0.667  0.019  1.0
  O  O16  1  0.000  0.000  0.971  1.0
  O  O17  1  0.000  0.000  0.471  1.0
  O  O18  1  0.355  0.000  0.828  1.0
  O  O19  1  0.355  0.355  0.328  1.0
  O  O20  1  0.000  0.645  0.328  1.0
  O  O21  1  0.000  0.355  0.828  1.0
  O  O22  1  0.645  0.645  0.828  1.0
  O  O23  1  0.645  0.000  0.328  1.0
  O  O24  1  0.314  0.000  0.175  1.0
  O  O25  1  0.314  0.314  0.675  1.0
  O  O26  1  0.000  0.686  0.675  1.0
  O  O27  1  0.000  0.314  0.175  1.0
  O  O28  1  0.686  0.686  0.175  1.0
  O  O29  1  0.686  0.000  0.675  1.0
[/CIF]
.