The material structure described by Cr2Se3 crystallizes in the trigonal P-31c space group. There are three inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to six equivalent Se(1) atoms to form a mixture of face and corner-sharing CrSe6 octahedra. The corner-sharing octahedral tilt angles range from 46-50°. In the second Cr site, Cr(2) is bonded to six equivalent Se(1) atoms to form a mixture of corner and edge-sharing CrSe6 octahedra. The corner-sharing octahedral tilt angles are 46°. In the third Cr site, Cr(3) is bonded to six equivalent Se(1) atoms to form a mixture of face, corner, and edge-sharing CrSe6 octahedra. The corner-sharing octahedral tilt angles are 50°. Se(1) is bonded in a rectangular see-saw-like geometry to one Cr(1), one Cr(2), and two equivalent Cr(3) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_Cr2Se3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.336
_cell_length_b   6.336
_cell_length_c   11.773
_cell_angle_alpha   90.003
_cell_angle_beta   89.999
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   409.370
_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
  Cr  Cr0  1  0.667  0.333  0.750  1.0
  Cr  Cr1  1  0.333  0.667  0.250  1.0
  Cr  Cr2  1  0.000  1.000  0.500  1.0
  Cr  Cr3  1  0.000  1.000  1.000  1.0
  Cr  Cr4  1  0.667  0.333  0.487  1.0
  Cr  Cr5  1  0.333  0.667  0.987  1.0
  Cr  Cr6  1  0.333  0.667  0.513  1.0
  Cr  Cr7  1  0.667  0.333  0.013  1.0
  Se  Se8  1  0.342  0.326  0.881  1.0
  Se  Se9  1  0.674  0.016  0.881  1.0
  Se  Se10  1  0.984  0.658  0.881  1.0
  Se  Se11  1  0.658  0.984  0.381  1.0
  Se  Se12  1  0.016  0.674  0.381  1.0
  Se  Se13  1  0.326  0.342  0.381  1.0
  Se  Se14  1  0.658  0.674  0.119  1.0
  Se  Se15  1  0.326  0.984  0.119  1.0
  Se  Se16  1  0.016  0.342  0.119  1.0
  Se  Se17  1  0.342  0.016  0.619  1.0
  Se  Se18  1  0.984  0.326  0.619  1.0
  Se  Se19  1  0.674  0.658  0.619  1.0
[/CIF]
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The material structure described by Cr2Se3 crystallizes in the trigonal P-31c space group. There are three inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to six equivalent Se(1) atoms to form a mixture of face and corner-sharing CrSe6 octahedra. The corner-sharing octahedral tilt angles range from 46-50°. In the second Cr site, Cr(2) is bonded to six equivalent Se(1) atoms to form a mixture of corner and edge-sharing CrSe6 octahedra. The corner-sharing octahedral tilt angles are 46°. In the third Cr site, Cr(3) is bonded to six equivalent Se(1) atoms to form a mixture of face, corner, and edge-sharing CrSe6 octahedra. The corner-sharing octahedral tilt angles are 50°. Se(1) is bonded in a rectangular see-saw-like geometry to one Cr(1), one Cr(2), and two equivalent Cr(3) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_Cr2Se3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.336
_cell_length_b   6.336
_cell_length_c   11.773
_cell_angle_alpha   90.003
_cell_angle_beta   89.999
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   409.370
_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
  Cr  Cr0  1  0.667  0.333  0.750  1.0
  Cr  Cr1  1  0.333  0.667  0.250  1.0
  Cr  Cr2  1  0.000  1.000  0.500  1.0
  Cr  Cr3  1  0.000  1.000  1.000  1.0
  Cr  Cr4  1  0.667  0.333  0.487  1.0
  Cr  Cr5  1  0.333  0.667  0.987  1.0
  Cr  Cr6  1  0.333  0.667  0.513  1.0
  Cr  Cr7  1  0.667  0.333  0.013  1.0
  Se  Se8  1  0.342  0.326  0.881  1.0
  Se  Se9  1  0.674  0.016  0.881  1.0
  Se  Se10  1  0.984  0.658  0.881  1.0
  Se  Se11  1  0.658  0.984  0.381  1.0
  Se  Se12  1  0.016  0.674  0.381  1.0
  Se  Se13  1  0.326  0.342  0.381  1.0
  Se  Se14  1  0.658  0.674  0.119  1.0
  Se  Se15  1  0.326  0.984  0.119  1.0
  Se  Se16  1  0.016  0.342  0.119  1.0
  Se  Se17  1  0.342  0.016  0.619  1.0
  Se  Se18  1  0.984  0.326  0.619  1.0
  Se  Se19  1  0.674  0.658  0.619  1.0
[/CIF]
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