The compound described by Cu4Sn7S16 is beta indium sulfide-derived structured and crystallizes in the trigonal R3m space group. There are four inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to three equivalent S(2) and three equivalent S(7) atoms to form CuS6 octahedra that share corners with three equivalent Cu(2)S4 trigonal pyramids, corners with three equivalent Cu(3)S4 trigonal pyramids, edges with three equivalent Sn(1)S6 octahedra, and edges with three equivalent Sn(3)S6 octahedra. In the second Cu site, Cu(2) is bonded to one S(3) and three equivalent S(2) atoms to form distorted CuS4 trigonal pyramids that share corners with three equivalent Cu(1)S6 octahedra, corners with three equivalent Sn(1)S6 octahedra, and corners with six equivalent Sn(3)S6 octahedra. The corner-sharing octahedral tilt angles range from 40-66°. In the third Cu site, Cu(3) is bonded to one S(6) and three equivalent S(7) atoms to form CuS4 trigonal pyramids that share corners with three equivalent Cu(1)S6 octahedra, corners with three equivalent Sn(3)S6 octahedra, and corners with six equivalent Sn(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 39-65°. In the fourth Cu site, Cu(4) is bonded to one S(8) and three equivalent S(4) atoms to form CuS4 tetrahedra that share corners with three equivalent Sn(2)S6 octahedra, corners with three equivalent Sn(3)S6 octahedra, and corners with six equivalent Sn(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 54-57°. There are three inequivalent Sn sites. In the first Sn site, Sn(1) is bonded to one S(1), one S(3), two equivalent S(4), and two equivalent S(7) atoms to form SnS6 octahedra that share corners with two equivalent Cu(4)S4 tetrahedra,  a cornercorner with one Cu(2)S4 trigonal pyramid, corners with two equivalent Cu(3)S4 trigonal pyramids,  an edgeedge with one Cu(1)S6 octahedra,  an edgeedge with one Sn(2)S6 octahedra, and edges with four equivalent Sn(1)S6 octahedra. In the second Sn site, Sn(2) is bonded to three equivalent S(4) and three equivalent S(5) atoms to form SnS6 octahedra that share corners with three equivalent Cu(4)S4 tetrahedra, edges with three equivalent Sn(1)S6 octahedra, and edges with three equivalent Sn(3)S6 octahedra. In the third Sn site, Sn(3) is bonded to one S(6), one S(8), two equivalent S(2), and two equivalent S(5) atoms to form SnS6 octahedra that share  a cornercorner with one Cu(4)S4 tetrahedra,  a cornercorner with one Cu(3)S4 trigonal pyramid, corners with two equivalent Cu(2)S4 trigonal pyramids,  an edgeedge with one Cu(1)S6 octahedra,  an edgeedge with one Sn(2)S6 octahedra, and edges with four equivalent Sn(3)S6 octahedra. There are eight inequivalent S sites. In the first S site, S(1) is bonded in a distorted T-shaped geometry to three equivalent Sn(1) atoms. In the second S site, S(2) is bonded in a rectangular see-saw-like geometry to one Cu(1), one Cu(2), and two equivalent Sn(3) atoms. In the third S site, S(3) is bonded in a distorted rectangular see-saw-like geometry to one Cu(2) and three equivalent Sn(1) atoms. In the fourth S site, S(4) is bonded in a distorted rectangular see-saw-like geometry to one Cu(4), one Sn(2), and two equivalent Sn(1) atoms. In the fifth S site, S(5) is bonded in a distorted T-shaped geometry to one Sn(2) and two equivalent Sn(3) atoms. In the sixth S site, S(6) is bonded in a distorted rectangular see-saw-like geometry to one Cu(3) and three equivalent Sn(3) atoms. In the seventh S site, S(7) is bonded in a rectangular see-saw-like geometry to one Cu(1), one Cu(3), and two equivalent Sn(1) atoms. In the eighth S site, S(8) is bonded in a rectangular see-saw-like geometry to one Cu(4) and three equivalent Sn(3) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_Cu4Sn7S16
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   12.953
_cell_length_b   12.953
_cell_length_c   12.953
_cell_angle_alpha   33.306
_cell_angle_beta   33.306
_cell_angle_gamma   33.306
_symmetry_Int_Tables_number   1
_cell_volume   583.490
_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  0.000  0.000  0.000  1.0
  Cu  Cu1  1  0.706  0.706  0.706  1.0
  Cu  Cu2  1  0.295  0.295  0.295  1.0
  Cu  Cu3  1  0.188  0.188  0.188  1.0
  Sn  Sn4  1  0.245  0.754  0.754  1.0
  Sn  Sn5  1  0.754  0.754  0.245  1.0
  Sn  Sn6  1  0.754  0.245  0.754  1.0
  Sn  Sn7  1  0.498  0.498  0.498  1.0
  Sn  Sn8  1  0.250  0.747  0.250  1.0
  Sn  Sn9  1  0.747  0.250  0.250  1.0
  Sn  Sn10  1  0.250  0.250  0.747  1.0
  S  S11  1  0.877  0.877  0.877  1.0
  S  S12  1  0.359  0.884  0.884  1.0
  S  S13  1  0.884  0.884  0.359  1.0
  S  S14  1  0.884  0.359  0.884  1.0
  S  S15  1  0.623  0.623  0.623  1.0
  S  S16  1  0.380  0.866  0.380  1.0
  S  S17  1  0.866  0.380  0.380  1.0
  S  S18  1  0.380  0.380  0.866  1.0
  S  S19  1  0.133  0.620  0.620  1.0
  S  S20  1  0.620  0.620  0.133  1.0
  S  S21  1  0.620  0.133  0.620  1.0
  S  S22  1  0.375  0.375  0.375  1.0
  S  S23  1  0.118  0.639  0.118  1.0
  S  S24  1  0.639  0.118  0.118  1.0
  S  S25  1  0.118  0.118  0.639  1.0
  S  S26  1  0.125  0.125  0.125  1.0
[/CIF]
.
The compound described by Cu4Sn7S16 is beta indium sulfide-derived structured and crystallizes in the trigonal R3m space group. There are four inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to three equivalent S(2) and three equivalent S(7) atoms to form CuS6 octahedra that share corners with three equivalent Cu(2)S4 trigonal pyramids, corners with three equivalent Cu(3)S4 trigonal pyramids, edges with three equivalent Sn(1)S6 octahedra, and edges with three equivalent Sn(3)S6 octahedra. In the second Cu site, Cu(2) is bonded to one S(3) and three equivalent S(2) atoms to form distorted CuS4 trigonal pyramids that share corners with three equivalent Cu(1)S6 octahedra, corners with three equivalent Sn(1)S6 octahedra, and corners with six equivalent Sn(3)S6 octahedra. The corner-sharing octahedral tilt angles range from 40-66°. In the third Cu site, Cu(3) is bonded to one S(6) and three equivalent S(7) atoms to form CuS4 trigonal pyramids that share corners with three equivalent Cu(1)S6 octahedra, corners with three equivalent Sn(3)S6 octahedra, and corners with six equivalent Sn(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 39-65°. In the fourth Cu site, Cu(4) is bonded to one S(8) and three equivalent S(4) atoms to form CuS4 tetrahedra that share corners with three equivalent Sn(2)S6 octahedra, corners with three equivalent Sn(3)S6 octahedra, and corners with six equivalent Sn(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 54-57°. There are three inequivalent Sn sites. In the first Sn site, Sn(1) is bonded to one S(1), one S(3), two equivalent S(4), and two equivalent S(7) atoms to form SnS6 octahedra that share corners with two equivalent Cu(4)S4 tetrahedra,  a cornercorner with one Cu(2)S4 trigonal pyramid, corners with two equivalent Cu(3)S4 trigonal pyramids,  an edgeedge with one Cu(1)S6 octahedra,  an edgeedge with one Sn(2)S6 octahedra, and edges with four equivalent Sn(1)S6 octahedra. In the second Sn site, Sn(2) is bonded to three equivalent S(4) and three equivalent S(5) atoms to form SnS6 octahedra that share corners with three equivalent Cu(4)S4 tetrahedra, edges with three equivalent Sn(1)S6 octahedra, and edges with three equivalent Sn(3)S6 octahedra. In the third Sn site, Sn(3) is bonded to one S(6), one S(8), two equivalent S(2), and two equivalent S(5) atoms to form SnS6 octahedra that share  a cornercorner with one Cu(4)S4 tetrahedra,  a cornercorner with one Cu(3)S4 trigonal pyramid, corners with two equivalent Cu(2)S4 trigonal pyramids,  an edgeedge with one Cu(1)S6 octahedra,  an edgeedge with one Sn(2)S6 octahedra, and edges with four equivalent Sn(3)S6 octahedra. There are eight inequivalent S sites. In the first S site, S(1) is bonded in a distorted T-shaped geometry to three equivalent Sn(1) atoms. In the second S site, S(2) is bonded in a rectangular see-saw-like geometry to one Cu(1), one Cu(2), and two equivalent Sn(3) atoms. In the third S site, S(3) is bonded in a distorted rectangular see-saw-like geometry to one Cu(2) and three equivalent Sn(1) atoms. In the fourth S site, S(4) is bonded in a distorted rectangular see-saw-like geometry to one Cu(4), one Sn(2), and two equivalent Sn(1) atoms. In the fifth S site, S(5) is bonded in a distorted T-shaped geometry to one Sn(2) and two equivalent Sn(3) atoms. In the sixth S site, S(6) is bonded in a distorted rectangular see-saw-like geometry to one Cu(3) and three equivalent Sn(3) atoms. In the seventh S site, S(7) is bonded in a rectangular see-saw-like geometry to one Cu(1), one Cu(3), and two equivalent Sn(1) atoms. In the eighth S site, S(8) is bonded in a rectangular see-saw-like geometry to one Cu(4) and three equivalent Sn(3) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_Cu4Sn7S16
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   12.953
_cell_length_b   12.953
_cell_length_c   12.953
_cell_angle_alpha   33.306
_cell_angle_beta   33.306
_cell_angle_gamma   33.306
_symmetry_Int_Tables_number   1
_cell_volume   583.490
_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  0.000  0.000  0.000  1.0
  Cu  Cu1  1  0.706  0.706  0.706  1.0
  Cu  Cu2  1  0.295  0.295  0.295  1.0
  Cu  Cu3  1  0.188  0.188  0.188  1.0
  Sn  Sn4  1  0.245  0.754  0.754  1.0
  Sn  Sn5  1  0.754  0.754  0.245  1.0
  Sn  Sn6  1  0.754  0.245  0.754  1.0
  Sn  Sn7  1  0.498  0.498  0.498  1.0
  Sn  Sn8  1  0.250  0.747  0.250  1.0
  Sn  Sn9  1  0.747  0.250  0.250  1.0
  Sn  Sn10  1  0.250  0.250  0.747  1.0
  S  S11  1  0.877  0.877  0.877  1.0
  S  S12  1  0.359  0.884  0.884  1.0
  S  S13  1  0.884  0.884  0.359  1.0
  S  S14  1  0.884  0.359  0.884  1.0
  S  S15  1  0.623  0.623  0.623  1.0
  S  S16  1  0.380  0.866  0.380  1.0
  S  S17  1  0.866  0.380  0.380  1.0
  S  S18  1  0.380  0.380  0.866  1.0
  S  S19  1  0.133  0.620  0.620  1.0
  S  S20  1  0.620  0.620  0.133  1.0
  S  S21  1  0.620  0.133  0.620  1.0
  S  S22  1  0.375  0.375  0.375  1.0
  S  S23  1  0.118  0.639  0.118  1.0
  S  S24  1  0.639  0.118  0.118  1.0
  S  S25  1  0.118  0.118  0.639  1.0
  S  S26  1  0.125  0.125  0.125  1.0
[/CIF]
.