The material structure described by NaCr3O8 crystallizes in the monoclinic C2/m space group. Na(1) is bonded to two equivalent O(2) and four equivalent O(3) atoms to form NaO6 octahedra that share corners with six equivalent Cr(2)O4 tetrahedra and edges with two equivalent Cr(1)O6 octahedra. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to two equivalent O(1) and four equivalent O(3) atoms to form CrO6 octahedra that share corners with six equivalent Cr(2)O4 tetrahedra and edges with two equivalent Na(1)O6 octahedra. In the second Cr site, Cr(2) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form CrO4 tetrahedra that share corners with three equivalent Na(1)O6 octahedra and corners with three equivalent Cr(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 34-63°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Cr(1) and one Cr(2) atom. In the second O site, O(2) is bonded in a distorted bent 120 degrees geometry to one Na(1) and one Cr(2) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Na(1), one Cr(1), and one Cr(2) atom. is represented by the CIF file [CIF]
data_NaCr3O8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.165
_cell_length_b   5.165
_cell_length_c   7.028
_cell_angle_alpha   90.083
_cell_angle_beta   90.083
_cell_angle_gamma   64.986
_symmetry_Int_Tables_number   1
_cell_volume   169.903
_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
  Cr  Cr0  1  1.000  1.000  0.500  1.0
  Cr  Cr1  1  0.643  0.643  0.724  1.0
  Cr  Cr2  1  0.357  0.357  0.276  1.0
  Na  Na3  1  0.000  1.000  1.000  1.0
  O  O4  1  0.776  0.776  0.556  1.0
  O  O5  1  0.224  0.224  0.444  1.0
  O  O6  1  0.278  0.278  0.068  1.0
  O  O7  1  0.722  0.722  0.932  1.0
  O  O8  1  0.720  0.215  0.296  1.0
  O  O9  1  0.785  0.280  0.704  1.0
  O  O10  1  0.280  0.785  0.704  1.0
  O  O11  1  0.215  0.720  0.296  1.0
[/CIF]
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The material structure described by NaCr3O8 crystallizes in the monoclinic C2/m space group. Na(1) is bonded to two equivalent O(2) and four equivalent O(3) atoms to form NaO6 octahedra that share corners with six equivalent Cr(2)O4 tetrahedra and edges with two equivalent Cr(1)O6 octahedra. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to two equivalent O(1) and four equivalent O(3) atoms to form CrO6 octahedra that share corners with six equivalent Cr(2)O4 tetrahedra and edges with two equivalent Na(1)O6 octahedra. In the second Cr site, Cr(2) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form CrO4 tetrahedra that share corners with three equivalent Na(1)O6 octahedra and corners with three equivalent Cr(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 34-63°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Cr(1) and one Cr(2) atom. In the second O site, O(2) is bonded in a distorted bent 120 degrees geometry to one Na(1) and one Cr(2) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Na(1), one Cr(1), and one Cr(2) atom. is represented by the CIF file [CIF]
data_NaCr3O8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.165
_cell_length_b   5.165
_cell_length_c   7.028
_cell_angle_alpha   90.083
_cell_angle_beta   90.083
_cell_angle_gamma   64.986
_symmetry_Int_Tables_number   1
_cell_volume   169.903
_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
  Cr  Cr0  1  1.000  1.000  0.500  1.0
  Cr  Cr1  1  0.643  0.643  0.724  1.0
  Cr  Cr2  1  0.357  0.357  0.276  1.0
  Na  Na3  1  0.000  1.000  1.000  1.0
  O  O4  1  0.776  0.776  0.556  1.0
  O  O5  1  0.224  0.224  0.444  1.0
  O  O6  1  0.278  0.278  0.068  1.0
  O  O7  1  0.722  0.722  0.932  1.0
  O  O8  1  0.720  0.215  0.296  1.0
  O  O9  1  0.785  0.280  0.704  1.0
  O  O10  1  0.280  0.785  0.704  1.0
  O  O11  1  0.215  0.720  0.296  1.0
[/CIF]
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