The material structure described by Na2(CrSe2)3 crystallizes in the monoclinic C2/m space group. Na(1) is bonded in a 6-coordinate geometry to two equivalent Se(2) and four equivalent Se(1) atoms. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to two equivalent Se(2) and four equivalent Se(1) atoms to form edge-sharing CrSe6 octahedra. In the second Cr site, Cr(2) is bonded to two equivalent Se(2) and four equivalent Se(1) atoms to form edge-sharing CrSe6 octahedra. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded to two equivalent Na(1), one Cr(1), and two equivalent Cr(2) atoms to form a mixture of corner and edge-sharing SeNa2Cr3 square pyramids. In the second Se site, Se(2) is bonded to two equivalent Na(1), one Cr(1), and two equivalent Cr(2) atoms to form a mixture of corner and edge-sharing SeNa2Cr3 square pyramids. is represented by the CIF card [CIF]
data_Na2(CrSe2)3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.251
_cell_length_b   6.251
_cell_length_c   7.420
_cell_angle_alpha   81.942
_cell_angle_beta   81.942
_cell_angle_gamma   120.212
_symmetry_Int_Tables_number   1
_cell_volume   240.438
_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  0.166  0.834  0.500  1.0
  Na  Na1  1  0.834  0.166  0.500  1.0
  Cr  Cr2  1  0.000  0.000  0.000  1.0
  Cr  Cr3  1  0.333  0.667  0.000  1.0
  Cr  Cr4  1  0.667  0.333  0.000  1.0
  Se  Se5  1  0.932  0.598  0.203  1.0
  Se  Se6  1  0.267  0.267  0.204  1.0
  Se  Se7  1  0.598  0.932  0.203  1.0
  Se  Se8  1  0.733  0.733  0.796  1.0
  Se  Se9  1  0.068  0.402  0.797  1.0
  Se  Se10  1  0.402  0.068  0.797  1.0
[/CIF]
.
The material structure described by Na2(CrSe2)3 crystallizes in the monoclinic C2/m space group. Na(1) is bonded in a 6-coordinate geometry to two equivalent Se(2) and four equivalent Se(1) atoms. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to two equivalent Se(2) and four equivalent Se(1) atoms to form edge-sharing CrSe6 octahedra. In the second Cr site, Cr(2) is bonded to two equivalent Se(2) and four equivalent Se(1) atoms to form edge-sharing CrSe6 octahedra. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded to two equivalent Na(1), one Cr(1), and two equivalent Cr(2) atoms to form a mixture of corner and edge-sharing SeNa2Cr3 square pyramids. In the second Se site, Se(2) is bonded to two equivalent Na(1), one Cr(1), and two equivalent Cr(2) atoms to form a mixture of corner and edge-sharing SeNa2Cr3 square pyramids. is represented by the CIF card [CIF]
data_Na2(CrSe2)3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.251
_cell_length_b   6.251
_cell_length_c   7.420
_cell_angle_alpha   81.942
_cell_angle_beta   81.942
_cell_angle_gamma   120.212
_symmetry_Int_Tables_number   1
_cell_volume   240.438
_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  0.166  0.834  0.500  1.0
  Na  Na1  1  0.834  0.166  0.500  1.0
  Cr  Cr2  1  0.000  0.000  0.000  1.0
  Cr  Cr3  1  0.333  0.667  0.000  1.0
  Cr  Cr4  1  0.667  0.333  0.000  1.0
  Se  Se5  1  0.932  0.598  0.203  1.0
  Se  Se6  1  0.267  0.267  0.204  1.0
  Se  Se7  1  0.598  0.932  0.203  1.0
  Se  Se8  1  0.733  0.733  0.796  1.0
  Se  Se9  1  0.068  0.402  0.797  1.0
  Se  Se10  1  0.402  0.068  0.797  1.0
[/CIF]
.