The material described by CrSe2 is trigonal omega-like structured and crystallizes in the triclinic P1 space group. There are four inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one Se(1), one Se(2), one Se(3), one Se(5), one Se(7), and one Se(8) atom to form edge-sharing CrSe6 octahedra. In the second Cr site, Cr(2) is bonded to one Se(1), one Se(2), one Se(4), one Se(6), one Se(7), and one Se(8) atom to form edge-sharing CrSe6 octahedra. In the third Cr site, Cr(3) is bonded to one Se(2), one Se(3), one Se(4), one Se(5), one Se(6), and one Se(7) atom to form edge-sharing CrSe6 octahedra. In the fourth Cr site, Cr(4) is bonded to one Se(1), one Se(3), one Se(4), one Se(5), one Se(6), and one Se(8) atom to form edge-sharing CrSe6 octahedra. There are eight inequivalent Se sites. In the first Se site, Se(1) is bonded in a distorted T-shaped geometry to one Cr(1), one Cr(2), and one Cr(4) atom. In the second Se site, Se(2) is bonded in a distorted T-shaped geometry to one Cr(1), one Cr(2), and one Cr(3) atom. In the third Se site, Se(3) is bonded in a distorted T-shaped geometry to one Cr(1), one Cr(3), and one Cr(4) atom. In the fourth Se site, Se(4) is bonded in a distorted T-shaped geometry to one Cr(2), one Cr(3), and one Cr(4) atom. In the fifth Se site, Se(5) is bonded in a distorted T-shaped geometry to one Cr(1), one Cr(3), and one Cr(4) atom. In the sixth Se site, Se(6) is bonded in a distorted T-shaped geometry to one Cr(2), one Cr(3), and one Cr(4) atom. In the seventh Se site, Se(7) is bonded in a distorted T-shaped geometry to one Cr(1), one Cr(2), and one Cr(3) atom. In the eighth Se site, Se(8) is bonded in a distorted T-shaped geometry to one Cr(1), one Cr(2), and one Cr(4) atom. is represented by the CIF card [CIF]
data_CrSe2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.150
_cell_length_b   7.138
_cell_length_c   7.180
_cell_angle_alpha   59.664
_cell_angle_beta   59.722
_cell_angle_gamma   59.907
_symmetry_Int_Tables_number   1
_cell_volume   257.724
_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  0.497  0.006  0.498  1.0
  Cr  Cr1  1  0.004  0.498  0.499  1.0
  Cr  Cr2  1  0.499  0.499  0.499  1.0
  Cr  Cr3  1  0.499  0.499  0.003  1.0
  Se  Se4  1  0.250  0.252  0.252  1.0
  Se  Se5  1  0.748  0.748  0.260  1.0
  Se  Se6  1  0.257  0.746  0.749  1.0
  Se  Se7  1  0.747  0.256  0.749  1.0
  Se  Se8  1  0.747  0.254  0.250  1.0
  Se  Se9  1  0.253  0.746  0.251  1.0
  Se  Se10  1  0.250  0.252  0.746  1.0
  Se  Se11  1  0.748  0.748  0.745  1.0
[/CIF]
.
The material described by CrSe2 is trigonal omega-like structured and crystallizes in the triclinic P1 space group. There are four inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one Se(1), one Se(2), one Se(3), one Se(5), one Se(7), and one Se(8) atom to form edge-sharing CrSe6 octahedra. In the second Cr site, Cr(2) is bonded to one Se(1), one Se(2), one Se(4), one Se(6), one Se(7), and one Se(8) atom to form edge-sharing CrSe6 octahedra. In the third Cr site, Cr(3) is bonded to one Se(2), one Se(3), one Se(4), one Se(5), one Se(6), and one Se(7) atom to form edge-sharing CrSe6 octahedra. In the fourth Cr site, Cr(4) is bonded to one Se(1), one Se(3), one Se(4), one Se(5), one Se(6), and one Se(8) atom to form edge-sharing CrSe6 octahedra. There are eight inequivalent Se sites. In the first Se site, Se(1) is bonded in a distorted T-shaped geometry to one Cr(1), one Cr(2), and one Cr(4) atom. In the second Se site, Se(2) is bonded in a distorted T-shaped geometry to one Cr(1), one Cr(2), and one Cr(3) atom. In the third Se site, Se(3) is bonded in a distorted T-shaped geometry to one Cr(1), one Cr(3), and one Cr(4) atom. In the fourth Se site, Se(4) is bonded in a distorted T-shaped geometry to one Cr(2), one Cr(3), and one Cr(4) atom. In the fifth Se site, Se(5) is bonded in a distorted T-shaped geometry to one Cr(1), one Cr(3), and one Cr(4) atom. In the sixth Se site, Se(6) is bonded in a distorted T-shaped geometry to one Cr(2), one Cr(3), and one Cr(4) atom. In the seventh Se site, Se(7) is bonded in a distorted T-shaped geometry to one Cr(1), one Cr(2), and one Cr(3) atom. In the eighth Se site, Se(8) is bonded in a distorted T-shaped geometry to one Cr(1), one Cr(2), and one Cr(4) atom. is represented by the CIF card [CIF]
data_CrSe2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.150
_cell_length_b   7.138
_cell_length_c   7.180
_cell_angle_alpha   59.664
_cell_angle_beta   59.722
_cell_angle_gamma   59.907
_symmetry_Int_Tables_number   1
_cell_volume   257.724
_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  0.497  0.006  0.498  1.0
  Cr  Cr1  1  0.004  0.498  0.499  1.0
  Cr  Cr2  1  0.499  0.499  0.499  1.0
  Cr  Cr3  1  0.499  0.499  0.003  1.0
  Se  Se4  1  0.250  0.252  0.252  1.0
  Se  Se5  1  0.748  0.748  0.260  1.0
  Se  Se6  1  0.257  0.746  0.749  1.0
  Se  Se7  1  0.747  0.256  0.749  1.0
  Se  Se8  1  0.747  0.254  0.250  1.0
  Se  Se9  1  0.253  0.746  0.251  1.0
  Se  Se10  1  0.250  0.252  0.746  1.0
  Se  Se11  1  0.748  0.748  0.745  1.0
[/CIF]
.