The compound described by K3TaNbCu3S8 crystallizes in the monoclinic C2 space group. There are three inequivalent K sites. In the first K site, K(1) is bonded in a body-centered cubic geometry to one S(3), one S(4), one S(7), one S(8), two equivalent S(5), and two equivalent S(6) atoms. In the second K site, K(2) is bonded in a 7-coordinate geometry to one S(2), one S(4), two equivalent S(1), and three equivalent S(7) atoms. In the third K site, K(3) is bonded in a 7-coordinate geometry to one S(1), one S(3), two equivalent S(2), and three equivalent S(8) atoms. Ta(1) is bonded to one S(1), one S(3), one S(5), and one S(7) atom to form TaS4 tetrahedra that share  an edgeedge with one Cu(3)S4 tetrahedra and edges with two equivalent Cu(1)S4 tetrahedra. Nb(1) is bonded to one S(2), one S(4), one S(6), and one S(8) atom to form NbS4 tetrahedra that share  an edgeedge with one Cu(4)S4 tetrahedra and edges with two equivalent Cu(2)S4 tetrahedra. There are four inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one S(1), one S(3), one S(5), and one S(7) atom to form distorted CuS4 tetrahedra that share corners with two equivalent Cu(3)S4 tetrahedra and edges with two equivalent Ta(1)S4 tetrahedra. In the second Cu site, Cu(2) is bonded to one S(2), one S(4), one S(6), and one S(8) atom to form distorted CuS4 tetrahedra that share corners with two equivalent Cu(4)S4 tetrahedra and edges with two equivalent Nb(1)S4 tetrahedra. In the third Cu site, Cu(3) is bonded to two equivalent S(3) and two equivalent S(5) atoms to form distorted CuS4 tetrahedra that share corners with four equivalent Cu(1)S4 tetrahedra and edges with two equivalent Ta(1)S4 tetrahedra. In the fourth Cu site, Cu(4) is bonded to two equivalent S(4) and two equivalent S(6) atoms to form distorted CuS4 tetrahedra that share corners with four equivalent Cu(2)S4 tetrahedra and edges with two equivalent Nb(1)S4 tetrahedra. There are eight inequivalent S sites. In the first S site, S(1) is bonded in a 5-coordinate geometry to one K(3), two equivalent K(2), one Ta(1), and one Cu(1) atom. In the second S site, S(2) is bonded in a 5-coordinate geometry to one K(2), two equivalent K(3), one Nb(1), and one Cu(2) atom. In the third S site, S(3) is bonded in a 5-coordinate geometry to one K(1), one K(3), one Ta(1), one Cu(1), and one Cu(3) atom. In the fourth S site, S(4) is bonded in a 5-coordinate geometry to one K(1), one K(2), one Nb(1), one Cu(2), and one Cu(4) atom. In the fifth S site, S(5) is bonded in a 5-coordinate geometry to two equivalent K(1), one Ta(1), one Cu(1), and one Cu(3) atom. In the sixth S site, S(6) is bonded in a 5-coordinate geometry to two equivalent K(1), one Nb(1), one Cu(2), and one Cu(4) atom. In the seventh S site, S(7) is bonded to one K(1), three equivalent K(2), one Ta(1), and one Cu(1) atom to form distorted SK4TaCu octahedra that share  a cornercorner with one S(8)K4NbCu octahedra, corners with two equivalent S(7)K4TaCu octahedra, and edges with two equivalent S(7)K4TaCu octahedra. The corner-sharing octahedral tilt angles range from 0-69°. In the eighth S site, S(8) is bonded to one K(1), three equivalent K(3), one Nb(1), and one Cu(2) atom to form distorted SK4NbCu octahedra that share  a cornercorner with one S(7)K4TaCu octahedra, corners with two equivalent S(8)K4NbCu octahedra, and edges with two equivalent S(8)K4NbCu octahedra. The corner-sharing octahedral tilt angles range from 0-69°. is represented by the Crystallographic Information File (CIF) [CIF]
data_K3TaNbCu3S8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   12.246
_cell_length_b   12.246
_cell_length_c   14.485
_cell_angle_alpha   60.506
_cell_angle_beta   60.506
_cell_angle_gamma   26.372
_symmetry_Int_Tables_number   1
_cell_volume   832.500
_cell_formula_units_Z   2
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
  K  K0  1  0.500  0.500  0.250  1.0
  K  K1  1  0.500  0.500  0.750  1.0
  K  K2  1  0.150  0.233  0.155  1.0
  K  K3  1  0.767  0.850  0.845  1.0
  K  K4  1  0.849  0.767  0.345  1.0
  K  K5  1  0.233  0.151  0.655  1.0
  Ta  Ta6  1  0.090  0.658  0.030  1.0
  Ta  Ta7  1  0.342  0.910  0.970  1.0
  Nb  Nb8  1  0.910  0.342  0.470  1.0
  Nb  Nb9  1  0.658  0.090  0.530  1.0
  Cu  Cu10  1  0.593  0.161  0.032  1.0
  Cu  Cu11  1  0.839  0.407  0.968  1.0
  Cu  Cu12  1  0.407  0.839  0.468  1.0
  Cu  Cu13  1  0.161  0.593  0.532  1.0
  Cu  Cu14  1  0.219  0.781  0.000  1.0
  Cu  Cu15  1  0.781  0.219  0.500  1.0
  S  S16  1  0.759  0.821  0.140  1.0
  S  S17  1  0.179  0.241  0.860  1.0
  S  S18  1  0.243  0.176  0.360  1.0
  S  S19  1  0.824  0.757  0.640  1.0
  S  S20  1  0.358  0.460  0.123  1.0
  S  S21  1  0.540  0.642  0.877  1.0
  S  S22  1  0.640  0.541  0.377  1.0
  S  S23  1  0.459  0.360  0.623  1.0
  S  S24  1  0.940  0.981  0.911  1.0
  S  S25  1  0.019  0.060  0.089  1.0
  S  S26  1  0.061  0.018  0.589  1.0
  S  S27  1  0.982  0.939  0.411  1.0
  S  S28  1  0.311  0.377  0.937  1.0
  S  S29  1  0.623  0.689  0.063  1.0
  S  S30  1  0.687  0.626  0.563  1.0
  S  S31  1  0.374  0.313  0.437  1.0
[/CIF]
.
The compound described by K3TaNbCu3S8 crystallizes in the monoclinic C2 space group. There are three inequivalent K sites. In the first K site, K(1) is bonded in a body-centered cubic geometry to one S(3), one S(4), one S(7), one S(8), two equivalent S(5), and two equivalent S(6) atoms. In the second K site, K(2) is bonded in a 7-coordinate geometry to one S(2), one S(4), two equivalent S(1), and three equivalent S(7) atoms. In the third K site, K(3) is bonded in a 7-coordinate geometry to one S(1), one S(3), two equivalent S(2), and three equivalent S(8) atoms. Ta(1) is bonded to one S(1), one S(3), one S(5), and one S(7) atom to form TaS4 tetrahedra that share  an edgeedge with one Cu(3)S4 tetrahedra and edges with two equivalent Cu(1)S4 tetrahedra. Nb(1) is bonded to one S(2), one S(4), one S(6), and one S(8) atom to form NbS4 tetrahedra that share  an edgeedge with one Cu(4)S4 tetrahedra and edges with two equivalent Cu(2)S4 tetrahedra. There are four inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one S(1), one S(3), one S(5), and one S(7) atom to form distorted CuS4 tetrahedra that share corners with two equivalent Cu(3)S4 tetrahedra and edges with two equivalent Ta(1)S4 tetrahedra. In the second Cu site, Cu(2) is bonded to one S(2), one S(4), one S(6), and one S(8) atom to form distorted CuS4 tetrahedra that share corners with two equivalent Cu(4)S4 tetrahedra and edges with two equivalent Nb(1)S4 tetrahedra. In the third Cu site, Cu(3) is bonded to two equivalent S(3) and two equivalent S(5) atoms to form distorted CuS4 tetrahedra that share corners with four equivalent Cu(1)S4 tetrahedra and edges with two equivalent Ta(1)S4 tetrahedra. In the fourth Cu site, Cu(4) is bonded to two equivalent S(4) and two equivalent S(6) atoms to form distorted CuS4 tetrahedra that share corners with four equivalent Cu(2)S4 tetrahedra and edges with two equivalent Nb(1)S4 tetrahedra. There are eight inequivalent S sites. In the first S site, S(1) is bonded in a 5-coordinate geometry to one K(3), two equivalent K(2), one Ta(1), and one Cu(1) atom. In the second S site, S(2) is bonded in a 5-coordinate geometry to one K(2), two equivalent K(3), one Nb(1), and one Cu(2) atom. In the third S site, S(3) is bonded in a 5-coordinate geometry to one K(1), one K(3), one Ta(1), one Cu(1), and one Cu(3) atom. In the fourth S site, S(4) is bonded in a 5-coordinate geometry to one K(1), one K(2), one Nb(1), one Cu(2), and one Cu(4) atom. In the fifth S site, S(5) is bonded in a 5-coordinate geometry to two equivalent K(1), one Ta(1), one Cu(1), and one Cu(3) atom. In the sixth S site, S(6) is bonded in a 5-coordinate geometry to two equivalent K(1), one Nb(1), one Cu(2), and one Cu(4) atom. In the seventh S site, S(7) is bonded to one K(1), three equivalent K(2), one Ta(1), and one Cu(1) atom to form distorted SK4TaCu octahedra that share  a cornercorner with one S(8)K4NbCu octahedra, corners with two equivalent S(7)K4TaCu octahedra, and edges with two equivalent S(7)K4TaCu octahedra. The corner-sharing octahedral tilt angles range from 0-69°. In the eighth S site, S(8) is bonded to one K(1), three equivalent K(3), one Nb(1), and one Cu(2) atom to form distorted SK4NbCu octahedra that share  a cornercorner with one S(7)K4TaCu octahedra, corners with two equivalent S(8)K4NbCu octahedra, and edges with two equivalent S(8)K4NbCu octahedra. The corner-sharing octahedral tilt angles range from 0-69°. is represented by the Crystallographic Information File (CIF) [CIF]
data_K3TaNbCu3S8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   12.246
_cell_length_b   12.246
_cell_length_c   14.485
_cell_angle_alpha   60.506
_cell_angle_beta   60.506
_cell_angle_gamma   26.372
_symmetry_Int_Tables_number   1
_cell_volume   832.500
_cell_formula_units_Z   2
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
  K  K0  1  0.500  0.500  0.250  1.0
  K  K1  1  0.500  0.500  0.750  1.0
  K  K2  1  0.150  0.233  0.155  1.0
  K  K3  1  0.767  0.850  0.845  1.0
  K  K4  1  0.849  0.767  0.345  1.0
  K  K5  1  0.233  0.151  0.655  1.0
  Ta  Ta6  1  0.090  0.658  0.030  1.0
  Ta  Ta7  1  0.342  0.910  0.970  1.0
  Nb  Nb8  1  0.910  0.342  0.470  1.0
  Nb  Nb9  1  0.658  0.090  0.530  1.0
  Cu  Cu10  1  0.593  0.161  0.032  1.0
  Cu  Cu11  1  0.839  0.407  0.968  1.0
  Cu  Cu12  1  0.407  0.839  0.468  1.0
  Cu  Cu13  1  0.161  0.593  0.532  1.0
  Cu  Cu14  1  0.219  0.781  0.000  1.0
  Cu  Cu15  1  0.781  0.219  0.500  1.0
  S  S16  1  0.759  0.821  0.140  1.0
  S  S17  1  0.179  0.241  0.860  1.0
  S  S18  1  0.243  0.176  0.360  1.0
  S  S19  1  0.824  0.757  0.640  1.0
  S  S20  1  0.358  0.460  0.123  1.0
  S  S21  1  0.540  0.642  0.877  1.0
  S  S22  1  0.640  0.541  0.377  1.0
  S  S23  1  0.459  0.360  0.623  1.0
  S  S24  1  0.940  0.981  0.911  1.0
  S  S25  1  0.019  0.060  0.089  1.0
  S  S26  1  0.061  0.018  0.589  1.0
  S  S27  1  0.982  0.939  0.411  1.0
  S  S28  1  0.311  0.377  0.937  1.0
  S  S29  1  0.623  0.689  0.063  1.0
  S  S30  1  0.687  0.626  0.563  1.0
  S  S31  1  0.374  0.313  0.437  1.0
[/CIF]
.