The compound described by Cr3AlO8 is trigonal omega-derived structured and crystallizes in the trigonal R-3m space group. Cr(1) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form CrO6 octahedra that share edges with two equivalent Al(1)O6 octahedra and edges with four equivalent Cr(1)O6 octahedra. Al(1) is bonded to six equivalent O(2) atoms to form AlO6 octahedra that share edges with six equivalent Cr(1)O6 octahedra. There are two inequivalent O sites. In the first O site, O(1) is bonded in a distorted T-shaped geometry to three equivalent Cr(1) atoms. In the second O site, O(2) is bonded in a distorted trigonal non-coplanar geometry to two equivalent Cr(1) and one Al(1) atom. is represented by the CIF card [CIF]
data_AlCr3O8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.833
_cell_length_b   5.833
_cell_length_c   5.833
_cell_angle_alpha   60.480
_cell_angle_beta   60.480
_cell_angle_gamma   60.480
_symmetry_Int_Tables_number   1
_cell_volume   141.882
_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  0.500  0.500  0.500  1.0
  Cr  Cr1  1  0.000  0.500  0.500  1.0
  Cr  Cr2  1  0.500  0.500  0.000  1.0
  Cr  Cr3  1  0.500  0.000  0.500  1.0
  O  O4  1  0.265  0.265  0.265  1.0
  O  O5  1  0.696  0.268  0.268  1.0
  O  O6  1  0.268  0.268  0.696  1.0
  O  O7  1  0.268  0.696  0.268  1.0
  O  O8  1  0.735  0.735  0.735  1.0
  O  O9  1  0.304  0.732  0.732  1.0
  O  O10  1  0.732  0.732  0.304  1.0
  O  O11  1  0.732  0.304  0.732  1.0
[/CIF]
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The compound described by Cr3AlO8 is trigonal omega-derived structured and crystallizes in the trigonal R-3m space group. Cr(1) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form CrO6 octahedra that share edges with two equivalent Al(1)O6 octahedra and edges with four equivalent Cr(1)O6 octahedra. Al(1) is bonded to six equivalent O(2) atoms to form AlO6 octahedra that share edges with six equivalent Cr(1)O6 octahedra. There are two inequivalent O sites. In the first O site, O(1) is bonded in a distorted T-shaped geometry to three equivalent Cr(1) atoms. In the second O site, O(2) is bonded in a distorted trigonal non-coplanar geometry to two equivalent Cr(1) and one Al(1) atom. is represented by the CIF card [CIF]
data_AlCr3O8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.833
_cell_length_b   5.833
_cell_length_c   5.833
_cell_angle_alpha   60.480
_cell_angle_beta   60.480
_cell_angle_gamma   60.480
_symmetry_Int_Tables_number   1
_cell_volume   141.882
_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  0.500  0.500  0.500  1.0
  Cr  Cr1  1  0.000  0.500  0.500  1.0
  Cr  Cr2  1  0.500  0.500  0.000  1.0
  Cr  Cr3  1  0.500  0.000  0.500  1.0
  O  O4  1  0.265  0.265  0.265  1.0
  O  O5  1  0.696  0.268  0.268  1.0
  O  O6  1  0.268  0.268  0.696  1.0
  O  O7  1  0.268  0.696  0.268  1.0
  O  O8  1  0.735  0.735  0.735  1.0
  O  O9  1  0.304  0.732  0.732  1.0
  O  O10  1  0.732  0.732  0.304  1.0
  O  O11  1  0.732  0.304  0.732  1.0
[/CIF]
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