The material described by Cr2Se3 crystallizes in the trigonal R-3 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 corner and edge-sharing CrSe6 octahedra. The corner-sharing octahedral tilt angles are 45°. In the second Cr site, Cr(2) 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 45-50°. 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 CIF card [CIF]
data_Cr2Se3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.929
_cell_length_b   6.929
_cell_length_c   6.929
_cell_angle_alpha   54.396
_cell_angle_beta   54.396
_cell_angle_gamma   54.398
_symmetry_Int_Tables_number   1
_cell_volume   204.479
_cell_formula_units_Z   2
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  0.000  0.000  0.000  1.0
  Cr  Cr1  1  0.500  0.500  0.500  1.0
  Cr  Cr2  1  0.324  0.324  0.324  1.0
  Cr  Cr3  1  0.676  0.676  0.676  1.0
  Se  Se4  1  0.596  0.904  0.262  1.0
  Se  Se5  1  0.262  0.596  0.904  1.0
  Se  Se6  1  0.904  0.262  0.596  1.0
  Se  Se7  1  0.404  0.096  0.738  1.0
  Se  Se8  1  0.738  0.404  0.096  1.0
  Se  Se9  1  0.096  0.738  0.404  1.0
[/CIF]
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The material described by Cr2Se3 crystallizes in the trigonal R-3 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 corner and edge-sharing CrSe6 octahedra. The corner-sharing octahedral tilt angles are 45°. In the second Cr site, Cr(2) 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 45-50°. 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 CIF card [CIF]
data_Cr2Se3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.929
_cell_length_b   6.929
_cell_length_c   6.929
_cell_angle_alpha   54.396
_cell_angle_beta   54.396
_cell_angle_gamma   54.398
_symmetry_Int_Tables_number   1
_cell_volume   204.479
_cell_formula_units_Z   2
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  0.000  0.000  0.000  1.0
  Cr  Cr1  1  0.500  0.500  0.500  1.0
  Cr  Cr2  1  0.324  0.324  0.324  1.0
  Cr  Cr3  1  0.676  0.676  0.676  1.0
  Se  Se4  1  0.596  0.904  0.262  1.0
  Se  Se5  1  0.262  0.596  0.904  1.0
  Se  Se6  1  0.904  0.262  0.596  1.0
  Se  Se7  1  0.404  0.096  0.738  1.0
  Se  Se8  1  0.738  0.404  0.096  1.0
  Se  Se9  1  0.096  0.738  0.404  1.0
[/CIF]
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