The compound described by NaCr2O4 crystallizes in the orthorhombic Pmmn space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 6-coordinate geometry to two equivalent O(3) and four equivalent O(1) atoms. In the second Na site, Na(2) is bonded in a 6-coordinate geometry to two equivalent O(2) and four equivalent O(1) atoms. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(2), one O(3), and four equivalent O(1) 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 Na(1), one Na(2), one Cr(2), and two equivalent Cr(1) atoms to form ONa2Cr3 trigonal bipyramids that share corners with five equivalent O(1)Na2Cr3 trigonal bipyramids, corners with two equivalent O(3)NaCr3 trigonal pyramids, edges with four equivalent O(1)Na2Cr3 trigonal bipyramids, and edges with two equivalent O(3)NaCr3 trigonal pyramids. In the second O site, O(2) is bonded in a distorted rectangular see-saw-like geometry to one Na(2), one Cr(1), and two equivalent Cr(2) atoms. In the third O site, O(3) is bonded to one Na(1), one Cr(1), and two equivalent Cr(2) atoms to form distorted ONaCr3 trigonal pyramids that share corners with four equivalent O(1)Na2Cr3 trigonal bipyramids, corners with three equivalent O(3)NaCr3 trigonal pyramids, and edges with four equivalent O(1)Na2Cr3 trigonal bipyramids. is represented by the CIF file [CIF]
data_NaCr2O4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.094
_cell_length_b   5.948
_cell_length_c   11.388
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   345.057
_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
  Na  Na0  1  0.030  0.500  0.000  1.0
  Na  Na1  1  0.356  0.500  0.500  1.0
  Na  Na2  1  0.644  0.000  0.000  1.0
  Na  Na3  1  0.970  0.000  0.500  1.0
  Cr  Cr4  1  0.003  0.000  0.756  1.0
  Cr  Cr5  1  0.997  0.500  0.744  1.0
  Cr  Cr6  1  0.003  0.000  0.244  1.0
  Cr  Cr7  1  0.997  0.500  0.256  1.0
  Cr  Cr8  1  0.500  0.250  0.750  1.0
  Cr  Cr9  1  0.500  0.750  0.750  1.0
  Cr  Cr10  1  0.500  0.750  0.250  1.0
  Cr  Cr11  1  0.500  0.250  0.250  1.0
  O  O12  1  0.159  0.752  0.342  1.0
  O  O13  1  0.159  0.752  0.658  1.0
  O  O14  1  0.159  0.248  0.342  1.0
  O  O15  1  0.159  0.248  0.658  1.0
  O  O16  1  0.328  0.000  0.840  1.0
  O  O17  1  0.328  0.000  0.160  1.0
  O  O18  1  0.316  0.500  0.834  1.0
  O  O19  1  0.316  0.500  0.166  1.0
  O  O20  1  0.684  0.000  0.334  1.0
  O  O21  1  0.684  0.000  0.666  1.0
  O  O22  1  0.672  0.500  0.340  1.0
  O  O23  1  0.672  0.500  0.660  1.0
  O  O24  1  0.841  0.748  0.158  1.0
  O  O25  1  0.841  0.252  0.158  1.0
  O  O26  1  0.841  0.748  0.842  1.0
  O  O27  1  0.841  0.252  0.842  1.0
[/CIF]
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The compound described by NaCr2O4 crystallizes in the orthorhombic Pmmn space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 6-coordinate geometry to two equivalent O(3) and four equivalent O(1) atoms. In the second Na site, Na(2) is bonded in a 6-coordinate geometry to two equivalent O(2) and four equivalent O(1) atoms. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(2), one O(3), and four equivalent O(1) 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 Na(1), one Na(2), one Cr(2), and two equivalent Cr(1) atoms to form ONa2Cr3 trigonal bipyramids that share corners with five equivalent O(1)Na2Cr3 trigonal bipyramids, corners with two equivalent O(3)NaCr3 trigonal pyramids, edges with four equivalent O(1)Na2Cr3 trigonal bipyramids, and edges with two equivalent O(3)NaCr3 trigonal pyramids. In the second O site, O(2) is bonded in a distorted rectangular see-saw-like geometry to one Na(2), one Cr(1), and two equivalent Cr(2) atoms. In the third O site, O(3) is bonded to one Na(1), one Cr(1), and two equivalent Cr(2) atoms to form distorted ONaCr3 trigonal pyramids that share corners with four equivalent O(1)Na2Cr3 trigonal bipyramids, corners with three equivalent O(3)NaCr3 trigonal pyramids, and edges with four equivalent O(1)Na2Cr3 trigonal bipyramids. is represented by the CIF file [CIF]
data_NaCr2O4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.094
_cell_length_b   5.948
_cell_length_c   11.388
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   345.057
_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
  Na  Na0  1  0.030  0.500  0.000  1.0
  Na  Na1  1  0.356  0.500  0.500  1.0
  Na  Na2  1  0.644  0.000  0.000  1.0
  Na  Na3  1  0.970  0.000  0.500  1.0
  Cr  Cr4  1  0.003  0.000  0.756  1.0
  Cr  Cr5  1  0.997  0.500  0.744  1.0
  Cr  Cr6  1  0.003  0.000  0.244  1.0
  Cr  Cr7  1  0.997  0.500  0.256  1.0
  Cr  Cr8  1  0.500  0.250  0.750  1.0
  Cr  Cr9  1  0.500  0.750  0.750  1.0
  Cr  Cr10  1  0.500  0.750  0.250  1.0
  Cr  Cr11  1  0.500  0.250  0.250  1.0
  O  O12  1  0.159  0.752  0.342  1.0
  O  O13  1  0.159  0.752  0.658  1.0
  O  O14  1  0.159  0.248  0.342  1.0
  O  O15  1  0.159  0.248  0.658  1.0
  O  O16  1  0.328  0.000  0.840  1.0
  O  O17  1  0.328  0.000  0.160  1.0
  O  O18  1  0.316  0.500  0.834  1.0
  O  O19  1  0.316  0.500  0.166  1.0
  O  O20  1  0.684  0.000  0.334  1.0
  O  O21  1  0.684  0.000  0.666  1.0
  O  O22  1  0.672  0.500  0.340  1.0
  O  O23  1  0.672  0.500  0.660  1.0
  O  O24  1  0.841  0.748  0.158  1.0
  O  O25  1  0.841  0.252  0.158  1.0
  O  O26  1  0.841  0.748  0.842  1.0
  O  O27  1  0.841  0.252  0.842  1.0
[/CIF]
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