The crystal structure described by Na3Cr is beta Cu3Ti-like structured and crystallizes in the tetragonal I4/mmm space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to eight equivalent Na(2) and four equivalent Cr(1) atoms to form distorted NaNa8Cr4 cuboctahedra that share corners with four equivalent Na(1)Na8Cr4 cuboctahedra, corners with eight equivalent Cr(1)Na12 cuboctahedra, corners with sixteen equivalent Na(2)Na4Cr4 cuboctahedra, edges with eight equivalent Na(2)Na4Cr4 cuboctahedra, edges with eight equivalent Na(1)Na8Cr4 cuboctahedra, faces with four equivalent Na(1)Na8Cr4 cuboctahedra, and faces with six equivalent Cr(1)Na12 cuboctahedra. In the second Na site, Na(2) is bonded to four equivalent Na(1) and four equivalent Cr(1) atoms to form distorted NaNa4Cr4 cuboctahedra that share corners with eight equivalent Na(2)Na4Cr4 cuboctahedra, corners with eight equivalent Na(1)Na8Cr4 cuboctahedra, corners with eight equivalent Cr(1)Na12 cuboctahedra, edges with four equivalent Na(1)Na8Cr4 cuboctahedra, edges with four equivalent Cr(1)Na12 cuboctahedra, edges with twelve equivalent Na(2)Na4Cr4 cuboctahedra, and faces with six equivalent Na(2)Na4Cr4 cuboctahedra. Cr(1) is bonded to four equivalent Na(1) and eight equivalent Na(2) atoms to form CrNa12 cuboctahedra that share corners with four equivalent Cr(1)Na12 cuboctahedra, corners with eight equivalent Na(1)Na8Cr4 cuboctahedra, corners with sixteen equivalent Na(2)Na4Cr4 cuboctahedra, edges with eight equivalent Na(2)Na4Cr4 cuboctahedra, edges with eight equivalent Cr(1)Na12 cuboctahedra, faces with four equivalent Cr(1)Na12 cuboctahedra, and faces with six equivalent Na(1)Na8Cr4 cuboctahedra. is represented by the Crystallographic Information File (CIF) [CIF]
data_Na3Cr
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.968
_cell_length_b   5.968
_cell_length_c   5.968
_cell_angle_alpha   130.920
_cell_angle_beta   130.920
_cell_angle_gamma   71.940
_symmetry_Int_Tables_number   1
_cell_volume   118.677
_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
  Na  Na0  1  0.500  0.500  0.000  1.0
  Na  Na1  1  0.250  0.750  0.500  1.0
  Na  Na2  1  0.750  0.250  0.500  1.0
  Cr  Cr3  1  0.000  0.000  0.000  1.0
[/CIF]
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The crystal structure described by Na3Cr is beta Cu3Ti-like structured and crystallizes in the tetragonal I4/mmm space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to eight equivalent Na(2) and four equivalent Cr(1) atoms to form distorted NaNa8Cr4 cuboctahedra that share corners with four equivalent Na(1)Na8Cr4 cuboctahedra, corners with eight equivalent Cr(1)Na12 cuboctahedra, corners with sixteen equivalent Na(2)Na4Cr4 cuboctahedra, edges with eight equivalent Na(2)Na4Cr4 cuboctahedra, edges with eight equivalent Na(1)Na8Cr4 cuboctahedra, faces with four equivalent Na(1)Na8Cr4 cuboctahedra, and faces with six equivalent Cr(1)Na12 cuboctahedra. In the second Na site, Na(2) is bonded to four equivalent Na(1) and four equivalent Cr(1) atoms to form distorted NaNa4Cr4 cuboctahedra that share corners with eight equivalent Na(2)Na4Cr4 cuboctahedra, corners with eight equivalent Na(1)Na8Cr4 cuboctahedra, corners with eight equivalent Cr(1)Na12 cuboctahedra, edges with four equivalent Na(1)Na8Cr4 cuboctahedra, edges with four equivalent Cr(1)Na12 cuboctahedra, edges with twelve equivalent Na(2)Na4Cr4 cuboctahedra, and faces with six equivalent Na(2)Na4Cr4 cuboctahedra. Cr(1) is bonded to four equivalent Na(1) and eight equivalent Na(2) atoms to form CrNa12 cuboctahedra that share corners with four equivalent Cr(1)Na12 cuboctahedra, corners with eight equivalent Na(1)Na8Cr4 cuboctahedra, corners with sixteen equivalent Na(2)Na4Cr4 cuboctahedra, edges with eight equivalent Na(2)Na4Cr4 cuboctahedra, edges with eight equivalent Cr(1)Na12 cuboctahedra, faces with four equivalent Cr(1)Na12 cuboctahedra, and faces with six equivalent Na(1)Na8Cr4 cuboctahedra. is represented by the Crystallographic Information File (CIF) [CIF]
data_Na3Cr
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.968
_cell_length_b   5.968
_cell_length_c   5.968
_cell_angle_alpha   130.920
_cell_angle_beta   130.920
_cell_angle_gamma   71.940
_symmetry_Int_Tables_number   1
_cell_volume   118.677
_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
  Na  Na0  1  0.500  0.500  0.000  1.0
  Na  Na1  1  0.250  0.750  0.500  1.0
  Na  Na2  1  0.750  0.250  0.500  1.0
  Cr  Cr3  1  0.000  0.000  0.000  1.0
[/CIF]
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