The structure described by CaCr2O4 crystallizes in the orthorhombic Imma space group. Ca(1) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form CaO6 octahedra that share corners with six equivalent Cr(2)O6 octahedra, edges with two equivalent Ca(1)O6 octahedra, edges with two equivalent Cr(2)O6 octahedra, and edges with four equivalent Cr(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 9-14°. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form CrO6 octahedra that share edges with two equivalent Cr(1)O6 octahedra, edges with four equivalent Ca(1)O6 octahedra, and edges with four equivalent Cr(2)O6 octahedra. In the second Cr site, Cr(2) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form CrO6 octahedra that share corners with six equivalent Ca(1)O6 octahedra, edges with two equivalent Ca(1)O6 octahedra, edges with two equivalent Cr(2)O6 octahedra, and edges with four equivalent Cr(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 9-14°. There are two inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to one Ca(1), one Cr(2), and two equivalent Cr(1) atoms. In the second O site, O(2) is bonded to two equivalent Ca(1), one Cr(1), and two equivalent Cr(2) atoms to form a mixture of edge and corner-sharing OCa2Cr3 square pyramids. is represented by the CIF card [CIF]
data_CaCr2O4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.180
_cell_length_b   6.180
_cell_length_c   6.180
_cell_angle_alpha   119.483
_cell_angle_beta   118.603
_cell_angle_gamma   91.667
_symmetry_Int_Tables_number   1
_cell_volume   169.214
_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
  Ca  Ca0  1  0.000  0.500  0.500  1.0
  Ca  Ca1  1  0.500  0.500  0.000  1.0
  Cr  Cr2  1  0.000  0.500  0.000  1.0
  Cr  Cr3  1  0.000  0.000  0.000  1.0
  Cr  Cr4  1  0.000  0.000  0.500  1.0
  Cr  Cr5  1  0.500  0.000  0.500  1.0
  O  O6  1  0.777  0.236  0.542  1.0
  O  O7  1  0.764  0.235  0.972  1.0
  O  O8  1  0.194  0.236  0.958  1.0
  O  O9  1  0.236  0.208  0.472  1.0
  O  O10  1  0.806  0.764  0.042  1.0
  O  O11  1  0.236  0.765  0.028  1.0
  O  O12  1  0.764  0.792  0.528  1.0
  O  O13  1  0.223  0.764  0.458  1.0
[/CIF]
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The structure described by CaCr2O4 crystallizes in the orthorhombic Imma space group. Ca(1) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form CaO6 octahedra that share corners with six equivalent Cr(2)O6 octahedra, edges with two equivalent Ca(1)O6 octahedra, edges with two equivalent Cr(2)O6 octahedra, and edges with four equivalent Cr(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 9-14°. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form CrO6 octahedra that share edges with two equivalent Cr(1)O6 octahedra, edges with four equivalent Ca(1)O6 octahedra, and edges with four equivalent Cr(2)O6 octahedra. In the second Cr site, Cr(2) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form CrO6 octahedra that share corners with six equivalent Ca(1)O6 octahedra, edges with two equivalent Ca(1)O6 octahedra, edges with two equivalent Cr(2)O6 octahedra, and edges with four equivalent Cr(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 9-14°. There are two inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to one Ca(1), one Cr(2), and two equivalent Cr(1) atoms. In the second O site, O(2) is bonded to two equivalent Ca(1), one Cr(1), and two equivalent Cr(2) atoms to form a mixture of edge and corner-sharing OCa2Cr3 square pyramids. is represented by the CIF card [CIF]
data_CaCr2O4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.180
_cell_length_b   6.180
_cell_length_c   6.180
_cell_angle_alpha   119.483
_cell_angle_beta   118.603
_cell_angle_gamma   91.667
_symmetry_Int_Tables_number   1
_cell_volume   169.214
_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
  Ca  Ca0  1  0.000  0.500  0.500  1.0
  Ca  Ca1  1  0.500  0.500  0.000  1.0
  Cr  Cr2  1  0.000  0.500  0.000  1.0
  Cr  Cr3  1  0.000  0.000  0.000  1.0
  Cr  Cr4  1  0.000  0.000  0.500  1.0
  Cr  Cr5  1  0.500  0.000  0.500  1.0
  O  O6  1  0.777  0.236  0.542  1.0
  O  O7  1  0.764  0.235  0.972  1.0
  O  O8  1  0.194  0.236  0.958  1.0
  O  O9  1  0.236  0.208  0.472  1.0
  O  O10  1  0.806  0.764  0.042  1.0
  O  O11  1  0.236  0.765  0.028  1.0
  O  O12  1  0.764  0.792  0.528  1.0
  O  O13  1  0.223  0.764  0.458  1.0
[/CIF]
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