The compound described by Cu19Se11 crystallizes in the triclinic P1 space group. There are nineteen inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one Se(1) and three equivalent Se(2) atoms to form CuSe4 trigonal pyramids that share corners with three equivalent Cu(2)CuSe4 tetrahedra and corners with six equivalent Cu(1)Se4 trigonal pyramids. In the second Cu site, Cu(2) is bonded to one Cu(3), one Se(2), and three equivalent Se(3) atoms to form distorted CuCuSe4 tetrahedra that share corners with six equivalent Cu(2)CuSe4 tetrahedra and corners with three equivalent Cu(1)Se4 trigonal pyramids. In the third Cu site, Cu(3) is bonded in a 9-coordinate geometry to one Cu(2), three equivalent Cu(4), two equivalent Se(3), and three equivalent Se(4) atoms. In the fourth Cu site, Cu(4) is bonded in a 4-coordinate geometry to three equivalent Cu(3), one Se(3), and three equivalent Se(4) atoms. In the fifth Cu site, Cu(5) is bonded to one Cu(6), one Se(4), and three equivalent Se(5) atoms to form distorted corner-sharing CuCuSe4 tetrahedra. In the sixth Cu site, Cu(6) is bonded in a 9-coordinate geometry to one Cu(5), three equivalent Cu(7), two equivalent Se(5), and three equivalent Se(6) atoms. In the seventh Cu site, Cu(7) is bonded in a 7-coordinate geometry to three equivalent Cu(6), one Se(5), and three equivalent Se(6) atoms. In the eighth Cu site, Cu(8) is bonded to one Se(6) and three equivalent Se(7) atoms to form corner-sharing CuSe4 tetrahedra. In the ninth Cu site, Cu(9) is bonded to one Se(9) and three equivalent Se(8) atoms to form distorted CuSe4 tetrahedra that share  a cornercorner with one Cu(15)CuSe4 tetrahedra, corners with three equivalent Cu(10)Se4 tetrahedra, corners with three equivalent Cu(11)Se4 tetrahedra, corners with six equivalent Cu(9)Se4 tetrahedra, edges with three equivalent Cu(11)Se4 tetrahedra, and edges with three equivalent Cu(13)Se4 tetrahedra. In the tenth Cu site, Cu(10) is bonded to one Se(10) and three equivalent Se(9) atoms to form distorted CuSe4 tetrahedra that share corners with three equivalent Cu(13)Se4 tetrahedra, corners with three equivalent Cu(9)Se4 tetrahedra, corners with six equivalent Cu(10)Se4 tetrahedra, edges with three equivalent Cu(15)CuSe4 tetrahedra, and edges with three equivalent Cu(13)Se4 tetrahedra. In the eleventh Cu site, Cu(11) is bonded to one Se(7) and three equivalent Se(8) atoms to form a mixture of distorted edge and corner-sharing CuSe4 tetrahedra. In the twelfth Cu site, Cu(12) is bonded in a 4-coordinate geometry to three equivalent Cu(16), one Se(11), and three equivalent Se(10) atoms. In the thirteenth Cu site, Cu(13) is bonded to one Se(8) and three equivalent Se(9) atoms to form distorted CuSe4 tetrahedra that share corners with three equivalent Cu(15)CuSe4 tetrahedra, corners with three equivalent Cu(10)Se4 tetrahedra, corners with three equivalent Cu(11)Se4 tetrahedra, corners with six equivalent Cu(13)Se4 tetrahedra, edges with three equivalent Cu(10)Se4 tetrahedra, and edges with three equivalent Cu(9)Se4 tetrahedra. In the fourteenth Cu site, Cu(14) is bonded in a 4-coordinate geometry to one Cu(16), three equivalent Cu(18), one Se(1), and three equivalent Se(11) atoms. In the fifteenth Cu site, Cu(15) is bonded to one Cu(16), one Se(9), and three equivalent Se(10) atoms to form distorted CuCuSe4 tetrahedra that share  a cornercorner with one Cu(9)Se4 tetrahedra, corners with three equivalent Cu(13)Se4 tetrahedra, corners with six equivalent Cu(15)CuSe4 tetrahedra, and edges with three equivalent Cu(10)Se4 tetrahedra. In the sixteenth Cu site, Cu(16) is bonded in a 13-coordinate geometry to one Cu(14), one Cu(15), three equivalent Cu(12), three equivalent Cu(17), two equivalent Se(10), and three equivalent Se(11) atoms. In the seventeenth Cu site, Cu(17) is bonded in a distorted trigonal non-coplanar geometry to one Cu(18), three equivalent Cu(16), and three equivalent Se(11) atoms. In the eighteenth Cu site, Cu(18) is bonded in a 12-coordinate geometry to one Cu(17), three equivalent Cu(14), three equivalent Cu(19), two equivalent Se(11), and three equivalent Se(1) atoms. In the nineteenth Cu site, Cu(19) is bonded in a 3-coordinate geometry to three equivalent Cu(18), one Se(11), and three equivalent Se(1) atoms. There are eleven inequivalent Se sites. In the first Se site, Se(1) is bonded in a 8-coordinate geometry to one Cu(1), one Cu(14), three equivalent Cu(18), and three equivalent Cu(19) atoms. In the second Se site, Se(2) is bonded to one Cu(2) and three equivalent Cu(1) atoms to form corner-sharing SeCu4 trigonal pyramids. In the third Se site, Se(3) is bonded in a distorted hexagonal planar geometry to one Cu(4), two equivalent Cu(3), and three equivalent Cu(2) atoms. In the fourth Se site, Se(4) is bonded in a 4-coordinate geometry to one Cu(5), three equivalent Cu(3), and three equivalent Cu(4) atoms. In the fifth Se site, Se(5) is bonded in a 5-coordinate geometry to one Cu(7), two equivalent Cu(6), and three equivalent Cu(5) atoms. In the sixth Se site, Se(6) is bonded in a 7-coordinate geometry to one Cu(8), three equivalent Cu(6), and three equivalent Cu(7) atoms. In the seventh Se site, Se(7) is bonded to one Cu(11) and three equivalent Cu(8) atoms to form corner-sharing SeCu4 tetrahedra. In the eighth Se site, Se(8) is bonded in a 7-coordinate geometry to one Cu(13), three equivalent Cu(11), and three equivalent Cu(9) atoms. In the ninth Se site, Se(9) is bonded in a body-centered cubic geometry to one Cu(15), one Cu(9), three equivalent Cu(10), and three equivalent Cu(13) atoms. In the tenth Se site, Se(10) is bonded in a 7-coordinate geometry to one Cu(10), two equivalent Cu(16), three equivalent Cu(12), and three equivalent Cu(15) atoms. In the eleventh Se site, Se(11) is bonded in a 10-coordinate geometry to one Cu(12), one Cu(19), two equivalent Cu(18), three equivalent Cu(14), three equivalent Cu(16), and three equivalent Cu(17) atoms. is represented by the CIF card [CIF]
data_Cu19Se11
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.975
_cell_length_b   4.112
_cell_length_c   36.108
_cell_angle_alpha   90.890
_cell_angle_beta   92.552
_cell_angle_gamma   117.597
_symmetry_Int_Tables_number   1
_cell_volume   522.066
_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  0.052  0.113  0.083  1.0
  Cu  Cu1  1  0.751  0.492  0.158  1.0
  Cu  Cu2  1  0.888  0.765  0.224  1.0
  Cu  Cu3  1  0.546  0.093  0.253  1.0
  Cu  Cu4  1  0.238  0.447  0.341  1.0
  Cu  Cu5  1  0.238  0.591  0.409  1.0
  Cu  Cu6  1  0.922  0.955  0.432  1.0
  Cu  Cu7  1  0.671  0.378  0.522  1.0
  Cu  Cu8  1  0.763  0.529  0.648  1.0
  Cu  Cu9  1  0.496  0.971  0.738  1.0
  Cu  Cu10  1  0.397  0.802  0.602  1.0
  Cu  Cu11  1  0.205  0.469  0.836  1.0
  Cu  Cu12  1  0.133  0.250  0.691  1.0
  Cu  Cu13  1  0.932  0.946  0.942  1.0
  Cu  Cu14  1  0.849  0.737  0.789  1.0
  Cu  Cu15  1  0.879  0.846  0.864  1.0
  Cu  Cu16  1  0.560  0.213  0.890  1.0
  Cu  Cu17  1  0.619  0.313  0.970  1.0
  Cu  Cu18  1  0.306  0.679  0.991  1.0
  Se  Se19  1  0.987  0.047  0.012  1.0
  Se  Se20  1  0.727  0.467  0.093  1.0
  Se  Se21  1  0.436  0.883  0.184  1.0
  Se  Se22  1  0.207  0.422  0.274  1.0
  Se  Se23  1  0.914  0.818  0.363  1.0
  Se  Se24  1  0.605  0.316  0.453  1.0
  Se  Se25  1  0.347  0.736  0.537  1.0
  Se  Se26  1  0.079  0.170  0.624  1.0
  Se  Se27  1  0.815  0.614  0.719  1.0
  Se  Se28  1  0.530  0.095  0.806  1.0
  Se  Se29  1  0.241  0.577  0.909  1.0
[/CIF]
.
The compound described by Cu19Se11 crystallizes in the triclinic P1 space group. There are nineteen inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one Se(1) and three equivalent Se(2) atoms to form CuSe4 trigonal pyramids that share corners with three equivalent Cu(2)CuSe4 tetrahedra and corners with six equivalent Cu(1)Se4 trigonal pyramids. In the second Cu site, Cu(2) is bonded to one Cu(3), one Se(2), and three equivalent Se(3) atoms to form distorted CuCuSe4 tetrahedra that share corners with six equivalent Cu(2)CuSe4 tetrahedra and corners with three equivalent Cu(1)Se4 trigonal pyramids. In the third Cu site, Cu(3) is bonded in a 9-coordinate geometry to one Cu(2), three equivalent Cu(4), two equivalent Se(3), and three equivalent Se(4) atoms. In the fourth Cu site, Cu(4) is bonded in a 4-coordinate geometry to three equivalent Cu(3), one Se(3), and three equivalent Se(4) atoms. In the fifth Cu site, Cu(5) is bonded to one Cu(6), one Se(4), and three equivalent Se(5) atoms to form distorted corner-sharing CuCuSe4 tetrahedra. In the sixth Cu site, Cu(6) is bonded in a 9-coordinate geometry to one Cu(5), three equivalent Cu(7), two equivalent Se(5), and three equivalent Se(6) atoms. In the seventh Cu site, Cu(7) is bonded in a 7-coordinate geometry to three equivalent Cu(6), one Se(5), and three equivalent Se(6) atoms. In the eighth Cu site, Cu(8) is bonded to one Se(6) and three equivalent Se(7) atoms to form corner-sharing CuSe4 tetrahedra. In the ninth Cu site, Cu(9) is bonded to one Se(9) and three equivalent Se(8) atoms to form distorted CuSe4 tetrahedra that share  a cornercorner with one Cu(15)CuSe4 tetrahedra, corners with three equivalent Cu(10)Se4 tetrahedra, corners with three equivalent Cu(11)Se4 tetrahedra, corners with six equivalent Cu(9)Se4 tetrahedra, edges with three equivalent Cu(11)Se4 tetrahedra, and edges with three equivalent Cu(13)Se4 tetrahedra. In the tenth Cu site, Cu(10) is bonded to one Se(10) and three equivalent Se(9) atoms to form distorted CuSe4 tetrahedra that share corners with three equivalent Cu(13)Se4 tetrahedra, corners with three equivalent Cu(9)Se4 tetrahedra, corners with six equivalent Cu(10)Se4 tetrahedra, edges with three equivalent Cu(15)CuSe4 tetrahedra, and edges with three equivalent Cu(13)Se4 tetrahedra. In the eleventh Cu site, Cu(11) is bonded to one Se(7) and three equivalent Se(8) atoms to form a mixture of distorted edge and corner-sharing CuSe4 tetrahedra. In the twelfth Cu site, Cu(12) is bonded in a 4-coordinate geometry to three equivalent Cu(16), one Se(11), and three equivalent Se(10) atoms. In the thirteenth Cu site, Cu(13) is bonded to one Se(8) and three equivalent Se(9) atoms to form distorted CuSe4 tetrahedra that share corners with three equivalent Cu(15)CuSe4 tetrahedra, corners with three equivalent Cu(10)Se4 tetrahedra, corners with three equivalent Cu(11)Se4 tetrahedra, corners with six equivalent Cu(13)Se4 tetrahedra, edges with three equivalent Cu(10)Se4 tetrahedra, and edges with three equivalent Cu(9)Se4 tetrahedra. In the fourteenth Cu site, Cu(14) is bonded in a 4-coordinate geometry to one Cu(16), three equivalent Cu(18), one Se(1), and three equivalent Se(11) atoms. In the fifteenth Cu site, Cu(15) is bonded to one Cu(16), one Se(9), and three equivalent Se(10) atoms to form distorted CuCuSe4 tetrahedra that share  a cornercorner with one Cu(9)Se4 tetrahedra, corners with three equivalent Cu(13)Se4 tetrahedra, corners with six equivalent Cu(15)CuSe4 tetrahedra, and edges with three equivalent Cu(10)Se4 tetrahedra. In the sixteenth Cu site, Cu(16) is bonded in a 13-coordinate geometry to one Cu(14), one Cu(15), three equivalent Cu(12), three equivalent Cu(17), two equivalent Se(10), and three equivalent Se(11) atoms. In the seventeenth Cu site, Cu(17) is bonded in a distorted trigonal non-coplanar geometry to one Cu(18), three equivalent Cu(16), and three equivalent Se(11) atoms. In the eighteenth Cu site, Cu(18) is bonded in a 12-coordinate geometry to one Cu(17), three equivalent Cu(14), three equivalent Cu(19), two equivalent Se(11), and three equivalent Se(1) atoms. In the nineteenth Cu site, Cu(19) is bonded in a 3-coordinate geometry to three equivalent Cu(18), one Se(11), and three equivalent Se(1) atoms. There are eleven inequivalent Se sites. In the first Se site, Se(1) is bonded in a 8-coordinate geometry to one Cu(1), one Cu(14), three equivalent Cu(18), and three equivalent Cu(19) atoms. In the second Se site, Se(2) is bonded to one Cu(2) and three equivalent Cu(1) atoms to form corner-sharing SeCu4 trigonal pyramids. In the third Se site, Se(3) is bonded in a distorted hexagonal planar geometry to one Cu(4), two equivalent Cu(3), and three equivalent Cu(2) atoms. In the fourth Se site, Se(4) is bonded in a 4-coordinate geometry to one Cu(5), three equivalent Cu(3), and three equivalent Cu(4) atoms. In the fifth Se site, Se(5) is bonded in a 5-coordinate geometry to one Cu(7), two equivalent Cu(6), and three equivalent Cu(5) atoms. In the sixth Se site, Se(6) is bonded in a 7-coordinate geometry to one Cu(8), three equivalent Cu(6), and three equivalent Cu(7) atoms. In the seventh Se site, Se(7) is bonded to one Cu(11) and three equivalent Cu(8) atoms to form corner-sharing SeCu4 tetrahedra. In the eighth Se site, Se(8) is bonded in a 7-coordinate geometry to one Cu(13), three equivalent Cu(11), and three equivalent Cu(9) atoms. In the ninth Se site, Se(9) is bonded in a body-centered cubic geometry to one Cu(15), one Cu(9), three equivalent Cu(10), and three equivalent Cu(13) atoms. In the tenth Se site, Se(10) is bonded in a 7-coordinate geometry to one Cu(10), two equivalent Cu(16), three equivalent Cu(12), and three equivalent Cu(15) atoms. In the eleventh Se site, Se(11) is bonded in a 10-coordinate geometry to one Cu(12), one Cu(19), two equivalent Cu(18), three equivalent Cu(14), three equivalent Cu(16), and three equivalent Cu(17) atoms. is represented by the CIF card [CIF]
data_Cu19Se11
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.975
_cell_length_b   4.112
_cell_length_c   36.108
_cell_angle_alpha   90.890
_cell_angle_beta   92.552
_cell_angle_gamma   117.597
_symmetry_Int_Tables_number   1
_cell_volume   522.066
_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  0.052  0.113  0.083  1.0
  Cu  Cu1  1  0.751  0.492  0.158  1.0
  Cu  Cu2  1  0.888  0.765  0.224  1.0
  Cu  Cu3  1  0.546  0.093  0.253  1.0
  Cu  Cu4  1  0.238  0.447  0.341  1.0
  Cu  Cu5  1  0.238  0.591  0.409  1.0
  Cu  Cu6  1  0.922  0.955  0.432  1.0
  Cu  Cu7  1  0.671  0.378  0.522  1.0
  Cu  Cu8  1  0.763  0.529  0.648  1.0
  Cu  Cu9  1  0.496  0.971  0.738  1.0
  Cu  Cu10  1  0.397  0.802  0.602  1.0
  Cu  Cu11  1  0.205  0.469  0.836  1.0
  Cu  Cu12  1  0.133  0.250  0.691  1.0
  Cu  Cu13  1  0.932  0.946  0.942  1.0
  Cu  Cu14  1  0.849  0.737  0.789  1.0
  Cu  Cu15  1  0.879  0.846  0.864  1.0
  Cu  Cu16  1  0.560  0.213  0.890  1.0
  Cu  Cu17  1  0.619  0.313  0.970  1.0
  Cu  Cu18  1  0.306  0.679  0.991  1.0
  Se  Se19  1  0.987  0.047  0.012  1.0
  Se  Se20  1  0.727  0.467  0.093  1.0
  Se  Se21  1  0.436  0.883  0.184  1.0
  Se  Se22  1  0.207  0.422  0.274  1.0
  Se  Se23  1  0.914  0.818  0.363  1.0
  Se  Se24  1  0.605  0.316  0.453  1.0
  Se  Se25  1  0.347  0.736  0.537  1.0
  Se  Se26  1  0.079  0.170  0.624  1.0
  Se  Se27  1  0.815  0.614  0.719  1.0
  Se  Se28  1  0.530  0.095  0.806  1.0
  Se  Se29  1  0.241  0.577  0.909  1.0
[/CIF]
.