The material described by Cu4Se3 crystallizes in the trigonal R-3m space group. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to three equivalent Se(1) and three equivalent Se(2) atoms to form a mixture of edge and corner-sharing CuSe6 octahedra. The corner-sharing octahedra are not tilted. In the second Cu site, Cu(2) is bonded in a 7-coordinate geometry to three equivalent Cu(2) and four equivalent Se(1) atoms. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded to three equivalent Cu(1) and four equivalent Cu(2) atoms to form distorted SeCu7 pentagonal bipyramids that share corners with three equivalent Se(2)Cu6 octahedra, edges with three equivalent Se(2)Cu6 octahedra, and edges with nine equivalent Se(1)Cu7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 3°. In the second Se site, Se(2) is bonded to six equivalent Cu(1) atoms to form SeCu6 octahedra that share corners with six equivalent Se(1)Cu7 pentagonal bipyramids, edges with six equivalent Se(2)Cu6 octahedra, and edges with six equivalent Se(1)Cu7 pentagonal bipyramids. is represented by the Crystallographic Information File (CIF) [CIF]
data_Cu4Se3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.776
_cell_length_b   3.776
_cell_length_c   9.872
_cell_angle_alpha   101.025
_cell_angle_beta   101.025
_cell_angle_gamma   60.000
_symmetry_Int_Tables_number   1
_cell_volume   118.871
_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
  Cu  Cu0  1  0.369  0.369  0.106  1.0
  Cu  Cu1  1  0.894  0.894  0.681  1.0
  Cu  Cu2  1  0.131  0.131  0.394  1.0
  Cu  Cu3  1  0.606  0.606  0.819  1.0
  Se  Se4  1  0.982  0.982  0.945  1.0
  Se  Se5  1  0.518  0.518  0.555  1.0
  Se  Se6  1  0.750  0.750  0.250  1.0
[/CIF]
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The material described by Cu4Se3 crystallizes in the trigonal R-3m space group. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to three equivalent Se(1) and three equivalent Se(2) atoms to form a mixture of edge and corner-sharing CuSe6 octahedra. The corner-sharing octahedra are not tilted. In the second Cu site, Cu(2) is bonded in a 7-coordinate geometry to three equivalent Cu(2) and four equivalent Se(1) atoms. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded to three equivalent Cu(1) and four equivalent Cu(2) atoms to form distorted SeCu7 pentagonal bipyramids that share corners with three equivalent Se(2)Cu6 octahedra, edges with three equivalent Se(2)Cu6 octahedra, and edges with nine equivalent Se(1)Cu7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 3°. In the second Se site, Se(2) is bonded to six equivalent Cu(1) atoms to form SeCu6 octahedra that share corners with six equivalent Se(1)Cu7 pentagonal bipyramids, edges with six equivalent Se(2)Cu6 octahedra, and edges with six equivalent Se(1)Cu7 pentagonal bipyramids. is represented by the Crystallographic Information File (CIF) [CIF]
data_Cu4Se3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.776
_cell_length_b   3.776
_cell_length_c   9.872
_cell_angle_alpha   101.025
_cell_angle_beta   101.025
_cell_angle_gamma   60.000
_symmetry_Int_Tables_number   1
_cell_volume   118.871
_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
  Cu  Cu0  1  0.369  0.369  0.106  1.0
  Cu  Cu1  1  0.894  0.894  0.681  1.0
  Cu  Cu2  1  0.131  0.131  0.394  1.0
  Cu  Cu3  1  0.606  0.606  0.819  1.0
  Se  Se4  1  0.982  0.982  0.945  1.0
  Se  Se5  1  0.518  0.518  0.555  1.0
  Se  Se6  1  0.750  0.750  0.250  1.0
[/CIF]
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