The structure described by Cu9Se8 crystallizes in the triclinic P1 space group. There are nine inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one Se(2) and three equivalent Se(1) atoms to form a mixture of edge and corner-sharing CuSe4 tetrahedra. In the second Cu site, Cu(2) is bonded to one Se(3) and three equivalent Se(2) atoms to form a mixture of distorted edge and corner-sharing CuSe4 tetrahedra. In the third Cu site, Cu(3) is bonded to one Se(2) and three equivalent Se(3) atoms to form a mixture of distorted edge and corner-sharing CuSe4 tetrahedra. In the fourth Cu site, Cu(4) is bonded to one Se(3) and three equivalent Se(5) atoms to form corner-sharing CuSe4 tetrahedra. In the fifth Cu site, Cu(5) is bonded to one Se(5) and three equivalent Se(4) atoms to form corner-sharing CuSe4 tetrahedra. In the sixth Cu site, Cu(6) is bonded to one Se(4) and three equivalent Se(6) atoms to form corner-sharing CuSe4 tetrahedra. In the seventh Cu site, Cu(7) is bonded to one Se(6) and three equivalent Se(7) atoms to form corner-sharing CuSe4 tetrahedra. In the eighth Cu site, Cu(8) is bonded to one Se(7) and three equivalent Se(8) atoms to form corner-sharing CuSe4 tetrahedra. In the ninth Cu site, Cu(9) is bonded to one Se(8) and three equivalent Se(1) atoms to form a mixture of edge and corner-sharing CuSe4 tetrahedra. There are eight inequivalent Se sites. In the first Se site, Se(1) is bonded in a 6-coordinate geometry to three equivalent Cu(1) and three equivalent Cu(9) atoms. In the second Se site, Se(2) is bonded in a 5-coordinate geometry to one Cu(1), one Cu(3), and three equivalent Cu(2) atoms. In the third Se site, Se(3) is bonded in a 5-coordinate geometry to one Cu(2), one Cu(4), and three equivalent Cu(3) atoms. In the fourth Se site, Se(4) is bonded to one Cu(6) and three equivalent Cu(5) atoms to form corner-sharing SeCu4 tetrahedra. In the fifth Se site, Se(5) is bonded to one Cu(5) and three equivalent Cu(4) atoms to form corner-sharing SeCu4 tetrahedra. In the sixth Se site, Se(6) is bonded to one Cu(7) and three equivalent Cu(6) atoms to form corner-sharing SeCu4 tetrahedra. In the seventh Se site, Se(7) is bonded to one Cu(8) and three equivalent Cu(7) atoms to form corner-sharing SeCu4 tetrahedra. In the eighth Se site, Se(8) is bonded to one Cu(9) and three equivalent Cu(8) atoms to form corner-sharing SeCu4 tetrahedra. is represented by the Crystallographic Information File (CIF) [CIF]
data_Cu9Se8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.855
_cell_length_b   3.872
_cell_length_c   31.088
_cell_angle_alpha   60.122
_cell_angle_beta   60.154
_cell_angle_gamma   60.203
_symmetry_Int_Tables_number   1
_cell_volume   329.352
_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  0.312  0.253  0.031  1.0
  Cu  Cu1  1  0.252  0.257  0.154  1.0
  Cu  Cu2  1  0.821  0.714  0.219  1.0
  Cu  Cu3  1  0.808  0.713  0.345  1.0
  Cu  Cu4  1  0.816  0.725  0.467  1.0
  Cu  Cu5  1  0.823  0.726  0.591  1.0
  Cu  Cu6  1  0.823  0.726  0.715  1.0
  Cu  Cu7  1  0.825  0.740  0.838  1.0
  Cu  Cu8  1  0.843  0.772  0.958  1.0
  Se  Se9  1  0.073  0.010  0.995  1.0
  Se  Se10  1  0.011  0.004  0.123  1.0
  Se  Se11  1  0.062  0.966  0.251  1.0
  Se  Se12  1  0.067  0.976  0.498  1.0
  Se  Se13  1  0.063  0.971  0.374  1.0
  Se  Se14  1  0.073  0.979  0.622  1.0
  Se  Se15  1  0.078  0.984  0.744  1.0
  Se  Se16  1  0.081  1.000  0.866  1.0
[/CIF]
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The structure described by Cu9Se8 crystallizes in the triclinic P1 space group. There are nine inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one Se(2) and three equivalent Se(1) atoms to form a mixture of edge and corner-sharing CuSe4 tetrahedra. In the second Cu site, Cu(2) is bonded to one Se(3) and three equivalent Se(2) atoms to form a mixture of distorted edge and corner-sharing CuSe4 tetrahedra. In the third Cu site, Cu(3) is bonded to one Se(2) and three equivalent Se(3) atoms to form a mixture of distorted edge and corner-sharing CuSe4 tetrahedra. In the fourth Cu site, Cu(4) is bonded to one Se(3) and three equivalent Se(5) atoms to form corner-sharing CuSe4 tetrahedra. In the fifth Cu site, Cu(5) is bonded to one Se(5) and three equivalent Se(4) atoms to form corner-sharing CuSe4 tetrahedra. In the sixth Cu site, Cu(6) is bonded to one Se(4) and three equivalent Se(6) atoms to form corner-sharing CuSe4 tetrahedra. In the seventh Cu site, Cu(7) is bonded to one Se(6) and three equivalent Se(7) atoms to form corner-sharing CuSe4 tetrahedra. In the eighth Cu site, Cu(8) is bonded to one Se(7) and three equivalent Se(8) atoms to form corner-sharing CuSe4 tetrahedra. In the ninth Cu site, Cu(9) is bonded to one Se(8) and three equivalent Se(1) atoms to form a mixture of edge and corner-sharing CuSe4 tetrahedra. There are eight inequivalent Se sites. In the first Se site, Se(1) is bonded in a 6-coordinate geometry to three equivalent Cu(1) and three equivalent Cu(9) atoms. In the second Se site, Se(2) is bonded in a 5-coordinate geometry to one Cu(1), one Cu(3), and three equivalent Cu(2) atoms. In the third Se site, Se(3) is bonded in a 5-coordinate geometry to one Cu(2), one Cu(4), and three equivalent Cu(3) atoms. In the fourth Se site, Se(4) is bonded to one Cu(6) and three equivalent Cu(5) atoms to form corner-sharing SeCu4 tetrahedra. In the fifth Se site, Se(5) is bonded to one Cu(5) and three equivalent Cu(4) atoms to form corner-sharing SeCu4 tetrahedra. In the sixth Se site, Se(6) is bonded to one Cu(7) and three equivalent Cu(6) atoms to form corner-sharing SeCu4 tetrahedra. In the seventh Se site, Se(7) is bonded to one Cu(8) and three equivalent Cu(7) atoms to form corner-sharing SeCu4 tetrahedra. In the eighth Se site, Se(8) is bonded to one Cu(9) and three equivalent Cu(8) atoms to form corner-sharing SeCu4 tetrahedra. is represented by the Crystallographic Information File (CIF) [CIF]
data_Cu9Se8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.855
_cell_length_b   3.872
_cell_length_c   31.088
_cell_angle_alpha   60.122
_cell_angle_beta   60.154
_cell_angle_gamma   60.203
_symmetry_Int_Tables_number   1
_cell_volume   329.352
_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  0.312  0.253  0.031  1.0
  Cu  Cu1  1  0.252  0.257  0.154  1.0
  Cu  Cu2  1  0.821  0.714  0.219  1.0
  Cu  Cu3  1  0.808  0.713  0.345  1.0
  Cu  Cu4  1  0.816  0.725  0.467  1.0
  Cu  Cu5  1  0.823  0.726  0.591  1.0
  Cu  Cu6  1  0.823  0.726  0.715  1.0
  Cu  Cu7  1  0.825  0.740  0.838  1.0
  Cu  Cu8  1  0.843  0.772  0.958  1.0
  Se  Se9  1  0.073  0.010  0.995  1.0
  Se  Se10  1  0.011  0.004  0.123  1.0
  Se  Se11  1  0.062  0.966  0.251  1.0
  Se  Se12  1  0.067  0.976  0.498  1.0
  Se  Se13  1  0.063  0.971  0.374  1.0
  Se  Se14  1  0.073  0.979  0.622  1.0
  Se  Se15  1  0.078  0.984  0.744  1.0
  Se  Se16  1  0.081  1.000  0.866  1.0
[/CIF]
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