The material structure described by BaCr2O4 crystallizes in the orthorhombic Pmmn space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 6-coordinate geometry to two equivalent O(1) and four equivalent O(3) atoms. In the second Ba site, Ba(2) is bonded in a 6-coordinate geometry to two equivalent O(2) and four equivalent O(3) atoms. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(1), one O(2), and four equivalent O(3) atoms to form edge-sharing CrO6 octahedra. In the second Cr site, Cr(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form edge-sharing CrO6 octahedra. There are three inequivalent O sites. In the first O site, O(1) is bonded to one Ba(1), one Cr(1), and two equivalent Cr(2) atoms to form distorted OBaCr3 trigonal pyramids that share corners with four equivalent O(3)Ba2Cr3 trigonal bipyramids, corners with three equivalent O(1)BaCr3 trigonal pyramids, corners with three equivalent O(2)BaCr3 trigonal pyramids, edges with four equivalent O(3)Ba2Cr3 trigonal bipyramids, and  an edgeedge with one O(2)BaCr3 trigonal pyramid. In the second O site, O(2) is bonded to one Ba(2), one Cr(1), and two equivalent Cr(2) atoms to form OBaCr3 trigonal pyramids that share corners with four equivalent O(3)Ba2Cr3 trigonal bipyramids, corners with three equivalent O(1)BaCr3 trigonal pyramids, corners with three equivalent O(2)BaCr3 trigonal pyramids, edges with four equivalent O(3)Ba2Cr3 trigonal bipyramids, and  an edgeedge with one O(1)BaCr3 trigonal pyramid. In the third O site, O(3) is bonded to one Ba(1), one Ba(2), one Cr(2), and two equivalent Cr(1) atoms to form distorted OBa2Cr3 trigonal bipyramids that share corners with five equivalent O(3)Ba2Cr3 trigonal bipyramids, corners with two equivalent O(1)BaCr3 trigonal pyramids, corners with two equivalent O(2)BaCr3 trigonal pyramids, edges with four equivalent O(3)Ba2Cr3 trigonal bipyramids, edges with two equivalent O(1)BaCr3 trigonal pyramids, and edges with two equivalent O(2)BaCr3 trigonal pyramids. is represented by the Crystallographic Information File (CIF) [CIF]
data_BaCr2O4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.191
_cell_length_b   5.978
_cell_length_c   12.327
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   382.525
_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
  Ba  Ba0  1  0.866  0.250  0.750  1.0
  Ba  Ba1  1  0.133  0.750  0.250  1.0
  Ba  Ba2  1  0.554  0.250  0.250  1.0
  Ba  Ba3  1  0.445  0.750  0.750  1.0
  Cr  Cr4  1  0.498  0.250  0.505  1.0
  Cr  Cr5  1  0.498  0.250  0.995  1.0
  Cr  Cr6  1  0.502  0.750  0.495  1.0
  Cr  Cr7  1  0.502  0.750  0.005  1.0
  Cr  Cr8  1  0.000  0.500  0.500  1.0
  Cr  Cr9  1  0.000  1.000  0.000  1.0
  Cr  Cr10  1  0.000  1.000  0.500  1.0
  Cr  Cr11  1  0.000  0.500  0.000  1.0
  O  O12  1  0.831  0.750  0.416  1.0
  O  O13  1  0.831  0.750  0.084  1.0
  O  O14  1  0.169  0.250  0.584  1.0
  O  O15  1  0.169  0.250  0.916  1.0
  O  O16  1  0.167  0.750  0.579  1.0
  O  O17  1  0.167  0.750  0.921  1.0
  O  O18  1  0.833  0.250  0.421  1.0
  O  O19  1  0.833  0.250  0.079  1.0
  O  O20  1  0.666  0.503  0.586  1.0
  O  O21  1  0.666  0.997  0.914  1.0
  O  O22  1  0.335  0.003  0.414  1.0
  O  O23  1  0.335  0.497  0.086  1.0
  O  O24  1  0.335  0.497  0.414  1.0
  O  O25  1  0.335  0.003  0.086  1.0
  O  O26  1  0.666  0.997  0.586  1.0
  O  O27  1  0.666  0.503  0.914  1.0
[/CIF]
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The material structure described by BaCr2O4 crystallizes in the orthorhombic Pmmn space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 6-coordinate geometry to two equivalent O(1) and four equivalent O(3) atoms. In the second Ba site, Ba(2) is bonded in a 6-coordinate geometry to two equivalent O(2) and four equivalent O(3) atoms. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(1), one O(2), and four equivalent O(3) atoms to form edge-sharing CrO6 octahedra. In the second Cr site, Cr(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form edge-sharing CrO6 octahedra. There are three inequivalent O sites. In the first O site, O(1) is bonded to one Ba(1), one Cr(1), and two equivalent Cr(2) atoms to form distorted OBaCr3 trigonal pyramids that share corners with four equivalent O(3)Ba2Cr3 trigonal bipyramids, corners with three equivalent O(1)BaCr3 trigonal pyramids, corners with three equivalent O(2)BaCr3 trigonal pyramids, edges with four equivalent O(3)Ba2Cr3 trigonal bipyramids, and  an edgeedge with one O(2)BaCr3 trigonal pyramid. In the second O site, O(2) is bonded to one Ba(2), one Cr(1), and two equivalent Cr(2) atoms to form OBaCr3 trigonal pyramids that share corners with four equivalent O(3)Ba2Cr3 trigonal bipyramids, corners with three equivalent O(1)BaCr3 trigonal pyramids, corners with three equivalent O(2)BaCr3 trigonal pyramids, edges with four equivalent O(3)Ba2Cr3 trigonal bipyramids, and  an edgeedge with one O(1)BaCr3 trigonal pyramid. In the third O site, O(3) is bonded to one Ba(1), one Ba(2), one Cr(2), and two equivalent Cr(1) atoms to form distorted OBa2Cr3 trigonal bipyramids that share corners with five equivalent O(3)Ba2Cr3 trigonal bipyramids, corners with two equivalent O(1)BaCr3 trigonal pyramids, corners with two equivalent O(2)BaCr3 trigonal pyramids, edges with four equivalent O(3)Ba2Cr3 trigonal bipyramids, edges with two equivalent O(1)BaCr3 trigonal pyramids, and edges with two equivalent O(2)BaCr3 trigonal pyramids. is represented by the Crystallographic Information File (CIF) [CIF]
data_BaCr2O4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.191
_cell_length_b   5.978
_cell_length_c   12.327
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   382.525
_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
  Ba  Ba0  1  0.866  0.250  0.750  1.0
  Ba  Ba1  1  0.133  0.750  0.250  1.0
  Ba  Ba2  1  0.554  0.250  0.250  1.0
  Ba  Ba3  1  0.445  0.750  0.750  1.0
  Cr  Cr4  1  0.498  0.250  0.505  1.0
  Cr  Cr5  1  0.498  0.250  0.995  1.0
  Cr  Cr6  1  0.502  0.750  0.495  1.0
  Cr  Cr7  1  0.502  0.750  0.005  1.0
  Cr  Cr8  1  0.000  0.500  0.500  1.0
  Cr  Cr9  1  0.000  1.000  0.000  1.0
  Cr  Cr10  1  0.000  1.000  0.500  1.0
  Cr  Cr11  1  0.000  0.500  0.000  1.0
  O  O12  1  0.831  0.750  0.416  1.0
  O  O13  1  0.831  0.750  0.084  1.0
  O  O14  1  0.169  0.250  0.584  1.0
  O  O15  1  0.169  0.250  0.916  1.0
  O  O16  1  0.167  0.750  0.579  1.0
  O  O17  1  0.167  0.750  0.921  1.0
  O  O18  1  0.833  0.250  0.421  1.0
  O  O19  1  0.833  0.250  0.079  1.0
  O  O20  1  0.666  0.503  0.586  1.0
  O  O21  1  0.666  0.997  0.914  1.0
  O  O22  1  0.335  0.003  0.414  1.0
  O  O23  1  0.335  0.497  0.086  1.0
  O  O24  1  0.335  0.497  0.414  1.0
  O  O25  1  0.335  0.003  0.086  1.0
  O  O26  1  0.666  0.997  0.586  1.0
  O  O27  1  0.666  0.503  0.914  1.0
[/CIF]
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