The material structure described by Cr2AlO4 crystallizes in the triclinic P-1 space group. There are four inequivalent Cr sites. In the first Cr site, Cr(1) is bonded in a distorted square co-planar geometry to two equivalent O(2) and two equivalent O(3) atoms. In the second Cr site, Cr(2) is bonded in a distorted square co-planar geometry to two equivalent O(1) and two equivalent O(4) atoms. In the third Cr site, Cr(3) is bonded in a square co-planar geometry to two equivalent O(2) and two equivalent O(4) atoms. In the fourth Cr site, Cr(4) is bonded in a square co-planar geometry to two equivalent O(1) and two equivalent O(3) atoms. Al(1) is bonded to one O(3), one O(4), two equivalent O(1), and two equivalent O(2) atoms to form distorted edge-sharing AlO6 pentagonal pyramids. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Cr(2), one Cr(4), and two equivalent Al(1) atoms to form a mixture of distorted edge and corner-sharing OAl2Cr2 tetrahedra. In the second O site, O(2) is bonded to one Cr(1), one Cr(3), and two equivalent Al(1) atoms to form a mixture of distorted edge and corner-sharing OAl2Cr2 trigonal pyramids. In the third O site, O(3) is bonded in a trigonal non-coplanar geometry to one Cr(1), one Cr(4), and one Al(1) atom. In the fourth O site, O(4) is bonded in a trigonal non-coplanar geometry to one Cr(2), one Cr(3), and one Al(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_AlCr2O4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.500
_cell_length_b   5.278
_cell_length_c   6.337
_cell_angle_alpha   111.389
_cell_angle_beta   112.652
_cell_angle_gamma   97.769
_symmetry_Int_Tables_number   1
_cell_volume   149.722
_cell_formula_units_Z   2
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  0.930  0.181  0.862  1.0
  Al  Al1  1  0.070  0.819  0.138  1.0
  Cr  Cr2  1  0.500  0.000  0.000  1.0
  Cr  Cr3  1  0.500  0.500  0.000  1.0
  Cr  Cr4  1  0.000  0.500  0.500  1.0
  Cr  Cr5  1  0.500  0.500  0.500  1.0
  O  O6  1  0.745  0.476  0.835  1.0
  O  O7  1  0.086  0.861  0.831  1.0
  O  O8  1  0.255  0.524  0.165  1.0
  O  O9  1  0.914  0.139  0.169  1.0
  O  O10  1  0.433  0.093  0.298  1.0
  O  O11  1  0.871  0.701  0.299  1.0
  O  O12  1  0.129  0.299  0.701  1.0
  O  O13  1  0.567  0.907  0.702  1.0
[/CIF]
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The material structure described by Cr2AlO4 crystallizes in the triclinic P-1 space group. There are four inequivalent Cr sites. In the first Cr site, Cr(1) is bonded in a distorted square co-planar geometry to two equivalent O(2) and two equivalent O(3) atoms. In the second Cr site, Cr(2) is bonded in a distorted square co-planar geometry to two equivalent O(1) and two equivalent O(4) atoms. In the third Cr site, Cr(3) is bonded in a square co-planar geometry to two equivalent O(2) and two equivalent O(4) atoms. In the fourth Cr site, Cr(4) is bonded in a square co-planar geometry to two equivalent O(1) and two equivalent O(3) atoms. Al(1) is bonded to one O(3), one O(4), two equivalent O(1), and two equivalent O(2) atoms to form distorted edge-sharing AlO6 pentagonal pyramids. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Cr(2), one Cr(4), and two equivalent Al(1) atoms to form a mixture of distorted edge and corner-sharing OAl2Cr2 tetrahedra. In the second O site, O(2) is bonded to one Cr(1), one Cr(3), and two equivalent Al(1) atoms to form a mixture of distorted edge and corner-sharing OAl2Cr2 trigonal pyramids. In the third O site, O(3) is bonded in a trigonal non-coplanar geometry to one Cr(1), one Cr(4), and one Al(1) atom. In the fourth O site, O(4) is bonded in a trigonal non-coplanar geometry to one Cr(2), one Cr(3), and one Al(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_AlCr2O4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.500
_cell_length_b   5.278
_cell_length_c   6.337
_cell_angle_alpha   111.389
_cell_angle_beta   112.652
_cell_angle_gamma   97.769
_symmetry_Int_Tables_number   1
_cell_volume   149.722
_cell_formula_units_Z   2
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  0.930  0.181  0.862  1.0
  Al  Al1  1  0.070  0.819  0.138  1.0
  Cr  Cr2  1  0.500  0.000  0.000  1.0
  Cr  Cr3  1  0.500  0.500  0.000  1.0
  Cr  Cr4  1  0.000  0.500  0.500  1.0
  Cr  Cr5  1  0.500  0.500  0.500  1.0
  O  O6  1  0.745  0.476  0.835  1.0
  O  O7  1  0.086  0.861  0.831  1.0
  O  O8  1  0.255  0.524  0.165  1.0
  O  O9  1  0.914  0.139  0.169  1.0
  O  O10  1  0.433  0.093  0.298  1.0
  O  O11  1  0.871  0.701  0.299  1.0
  O  O12  1  0.129  0.299  0.701  1.0
  O  O13  1  0.567  0.907  0.702  1.0
[/CIF]
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