The material described by Cr2Se3 crystallizes in the triclinic P-1 space group. There are four inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one Se(1), one Se(3), one Se(4), one Se(6), and two equivalent Se(2) atoms to form a mixture of edge, face, and corner-sharing CrSe6 octahedra. The corner-sharing octahedral tilt angles range from 46-52°. In the second Cr site, Cr(2) is bonded to one Se(2), one Se(6), two equivalent Se(1), and two equivalent Se(4) atoms to form a mixture of edge, face, and corner-sharing CrSe6 octahedra. The corner-sharing octahedral tilt angles range from 47-52°. In the third Cr site, Cr(3) is bonded to one Se(1), one Se(2), one Se(3), one Se(6), and two equivalent Se(5) atoms to form a mixture of edge and corner-sharing CrSe6 octahedra. The corner-sharing octahedral tilt angles range from 48-52°. In the fourth Cr site, Cr(4) is bonded to one Se(2), one Se(4), one Se(5), one Se(6), and two equivalent Se(3) atoms to form a mixture of edge, face, and corner-sharing CrSe6 octahedra. The corner-sharing octahedral tilt angles range from 46-52°. There are six inequivalent Se sites. In the first Se site, Se(1) is bonded in a rectangular see-saw-like geometry to one Cr(1), one Cr(3), and two equivalent Cr(2) atoms. In the second Se site, Se(2) is bonded to one Cr(2), one Cr(3), one Cr(4), and two equivalent Cr(1) atoms to form distorted SeCr5 square pyramids that share  a cornercorner with one Se(3)Cr4 trigonal pyramid,  an edgeedge with one Se(2)Cr5 square pyramid, and edges with two equivalent Se(3)Cr4 trigonal pyramids. In the third Se site, Se(3) is bonded to one Cr(1), one Cr(3), and two equivalent Cr(4) atoms to form SeCr4 trigonal pyramids that share  a cornercorner with one Se(2)Cr5 square pyramid, edges with two equivalent Se(2)Cr5 square pyramids, and  an edgeedge with one Se(3)Cr4 trigonal pyramid. In the fourth Se site, Se(4) is bonded in a rectangular see-saw-like geometry to one Cr(1), one Cr(4), and two equivalent Cr(2) atoms. In the fifth Se site, Se(5) is bonded in a distorted T-shaped geometry to one Cr(4) and two equivalent Cr(3) atoms. In the sixth Se site, Se(6) is bonded in a rectangular see-saw-like geometry to one Cr(1), one Cr(2), one Cr(3), and one Cr(4) atom. is represented by the CIF card [CIF]
data_Cr2Se3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.962
_cell_length_b   7.306
_cell_length_c   8.605
_cell_angle_alpha   89.548
_cell_angle_beta   104.115
_cell_angle_gamma   106.183
_symmetry_Int_Tables_number   1
_cell_volume   406.838
_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  0.831  0.330  0.330  1.0
  Cr  Cr1  1  0.169  0.670  0.670  1.0
  Cr  Cr2  1  0.527  0.750  0.498  1.0
  Cr  Cr3  1  0.843  0.075  0.843  1.0
  Cr  Cr4  1  0.180  0.407  0.153  1.0
  Cr  Cr5  1  0.473  0.250  0.502  1.0
  Cr  Cr6  1  0.820  0.593  0.847  1.0
  Cr  Cr7  1  0.157  0.925  0.157  1.0
  Se  Se8  1  0.543  0.023  0.312  1.0
  Se  Se9  1  0.876  0.349  0.640  1.0
  Se  Se10  1  0.209  0.682  0.972  1.0
  Se  Se11  1  0.457  0.977  0.688  1.0
  Se  Se12  1  0.791  0.318  0.028  1.0
  Se  Se13  1  0.124  0.651  0.360  1.0
  Se  Se14  1  0.443  0.494  0.694  1.0
  Se  Se15  1  0.781  0.824  0.031  1.0
  Se  Se16  1  0.104  0.152  0.353  1.0
  Se  Se17  1  0.557  0.506  0.306  1.0
  Se  Se18  1  0.896  0.848  0.647  1.0
  Se  Se19  1  0.219  0.176  0.969  1.0
[/CIF]
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The material described by Cr2Se3 crystallizes in the triclinic P-1 space group. There are four inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one Se(1), one Se(3), one Se(4), one Se(6), and two equivalent Se(2) atoms to form a mixture of edge, face, and corner-sharing CrSe6 octahedra. The corner-sharing octahedral tilt angles range from 46-52°. In the second Cr site, Cr(2) is bonded to one Se(2), one Se(6), two equivalent Se(1), and two equivalent Se(4) atoms to form a mixture of edge, face, and corner-sharing CrSe6 octahedra. The corner-sharing octahedral tilt angles range from 47-52°. In the third Cr site, Cr(3) is bonded to one Se(1), one Se(2), one Se(3), one Se(6), and two equivalent Se(5) atoms to form a mixture of edge and corner-sharing CrSe6 octahedra. The corner-sharing octahedral tilt angles range from 48-52°. In the fourth Cr site, Cr(4) is bonded to one Se(2), one Se(4), one Se(5), one Se(6), and two equivalent Se(3) atoms to form a mixture of edge, face, and corner-sharing CrSe6 octahedra. The corner-sharing octahedral tilt angles range from 46-52°. There are six inequivalent Se sites. In the first Se site, Se(1) is bonded in a rectangular see-saw-like geometry to one Cr(1), one Cr(3), and two equivalent Cr(2) atoms. In the second Se site, Se(2) is bonded to one Cr(2), one Cr(3), one Cr(4), and two equivalent Cr(1) atoms to form distorted SeCr5 square pyramids that share  a cornercorner with one Se(3)Cr4 trigonal pyramid,  an edgeedge with one Se(2)Cr5 square pyramid, and edges with two equivalent Se(3)Cr4 trigonal pyramids. In the third Se site, Se(3) is bonded to one Cr(1), one Cr(3), and two equivalent Cr(4) atoms to form SeCr4 trigonal pyramids that share  a cornercorner with one Se(2)Cr5 square pyramid, edges with two equivalent Se(2)Cr5 square pyramids, and  an edgeedge with one Se(3)Cr4 trigonal pyramid. In the fourth Se site, Se(4) is bonded in a rectangular see-saw-like geometry to one Cr(1), one Cr(4), and two equivalent Cr(2) atoms. In the fifth Se site, Se(5) is bonded in a distorted T-shaped geometry to one Cr(4) and two equivalent Cr(3) atoms. In the sixth Se site, Se(6) is bonded in a rectangular see-saw-like geometry to one Cr(1), one Cr(2), one Cr(3), and one Cr(4) atom. is represented by the CIF card [CIF]
data_Cr2Se3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.962
_cell_length_b   7.306
_cell_length_c   8.605
_cell_angle_alpha   89.548
_cell_angle_beta   104.115
_cell_angle_gamma   106.183
_symmetry_Int_Tables_number   1
_cell_volume   406.838
_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  0.831  0.330  0.330  1.0
  Cr  Cr1  1  0.169  0.670  0.670  1.0
  Cr  Cr2  1  0.527  0.750  0.498  1.0
  Cr  Cr3  1  0.843  0.075  0.843  1.0
  Cr  Cr4  1  0.180  0.407  0.153  1.0
  Cr  Cr5  1  0.473  0.250  0.502  1.0
  Cr  Cr6  1  0.820  0.593  0.847  1.0
  Cr  Cr7  1  0.157  0.925  0.157  1.0
  Se  Se8  1  0.543  0.023  0.312  1.0
  Se  Se9  1  0.876  0.349  0.640  1.0
  Se  Se10  1  0.209  0.682  0.972  1.0
  Se  Se11  1  0.457  0.977  0.688  1.0
  Se  Se12  1  0.791  0.318  0.028  1.0
  Se  Se13  1  0.124  0.651  0.360  1.0
  Se  Se14  1  0.443  0.494  0.694  1.0
  Se  Se15  1  0.781  0.824  0.031  1.0
  Se  Se16  1  0.104  0.152  0.353  1.0
  Se  Se17  1  0.557  0.506  0.306  1.0
  Se  Se18  1  0.896  0.848  0.647  1.0
  Se  Se19  1  0.219  0.176  0.969  1.0
[/CIF]
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