The material structure described by Er3Cu5Tl2S8 crystallizes in the monoclinic Cm space group. There are three inequivalent Er sites. In the first Er site, Er(1) is bonded to one S(5), one S(8), two equivalent S(6), and two equivalent S(7) atoms to form ErS6 octahedra that share  a cornercorner with one Er(3)S6 octahedra, corners with four equivalent Cu(4)S4 tetrahedra, edges with two equivalent Er(1)S6 octahedra, edges with two equivalent Er(2)S6 octahedra,  an edgeedge with one Cu(4)S4 tetrahedra, edges with two equivalent Cu(2)S4 tetrahedra, and edges with two equivalent Cu(5)S4 tetrahedra. The corner-sharing octahedral tilt angles are 33°. In the second Er site, Er(2) is bonded to one S(2), one S(7), two equivalent S(3), and two equivalent S(8) atoms to form ErS6 octahedra that share  a cornercorner with one Er(3)S6 octahedra, corners with four equivalent Cu(5)S4 tetrahedra, edges with two equivalent Er(1)S6 octahedra, edges with two equivalent Er(2)S6 octahedra,  an edgeedge with one Cu(5)S4 tetrahedra, edges with two equivalent Cu(1)S4 tetrahedra, and edges with two equivalent Cu(4)S4 tetrahedra. The corner-sharing octahedral tilt angles are 27°. In the third Er site, Er(3) is bonded to one S(2), one S(5), two equivalent S(1), and two equivalent S(4) atoms to form distorted ErS6 octahedra that share  a cornercorner with one Er(1)S6 octahedra,  a cornercorner with one Er(2)S6 octahedra, edges with two equivalent Er(3)S6 octahedra, edges with two equivalent Cu(1)S4 tetrahedra, and edges with two equivalent Cu(2)S4 tetrahedra. The corner-sharing octahedral tilt angles range from 27-33°. There are five inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one S(1), one S(3), and two equivalent S(2) atoms to form CuS4 tetrahedra that share  a cornercorner with one Cu(4)S4 tetrahedra,  a cornercorner with one Cu(5)S4 tetrahedra, corners with two equivalent Cu(1)S4 tetrahedra, edges with two equivalent Er(2)S6 octahedra, and edges with two equivalent Er(3)S6 octahedra. In the second Cu site, Cu(2) is bonded to one S(4), one S(6), and two equivalent S(5) atoms to form CuS4 tetrahedra that share  a cornercorner with one Cu(4)S4 tetrahedra,  a cornercorner with one Cu(5)S4 tetrahedra, corners with two equivalent Cu(2)S4 tetrahedra, edges with two equivalent Er(1)S6 octahedra, and edges with two equivalent Er(3)S6 octahedra. In the third Cu site, Cu(3) is bonded in a distorted trigonal planar geometry to one Tl(1), one S(4), and two equivalent S(1) atoms. In the fourth Cu site, Cu(4) is bonded to one S(3), one S(6), and two equivalent S(7) atoms to form distorted CuS4 tetrahedra that share corners with four equivalent Er(1)S6 octahedra,  a cornercorner with one Cu(1)S4 tetrahedra,  a cornercorner with one Cu(2)S4 tetrahedra, corners with two equivalent Cu(4)S4 tetrahedra,  an edgeedge with one Er(1)S6 octahedra, edges with two equivalent Er(2)S6 octahedra, and  an edgeedge with one Cu(5)S4 tetrahedra. The corner-sharing octahedral tilt angles range from 13-59°. In the fifth Cu site, Cu(5) is bonded to one S(3), one S(6), and two equivalent S(8) atoms to form distorted CuS4 tetrahedra that share corners with four equivalent Er(2)S6 octahedra,  a cornercorner with one Cu(1)S4 tetrahedra,  a cornercorner with one Cu(2)S4 tetrahedra, corners with two equivalent Cu(5)S4 tetrahedra,  an edgeedge with one Er(2)S6 octahedra, edges with two equivalent Er(1)S6 octahedra, and  an edgeedge with one Cu(4)S4 tetrahedra. The corner-sharing octahedral tilt angles range from 13-59°. There are two inequivalent Tl sites. In the first Tl site, Tl(1) is bonded in a 4-coordinate geometry to one Cu(3), one S(8), and two equivalent S(2) atoms. In the second Tl site, Tl(2) is bonded in a 1-coordinate geometry to one S(7) atom. There are eight inequivalent S sites. In the first S site, S(1) is bonded in a 5-coordinate geometry to two equivalent Er(3), one Cu(1), and two equivalent Cu(3) atoms. In the second S site, S(2) is bonded in a 4-coordinate geometry to one Er(2), one Er(3), two equivalent Cu(1), and two equivalent Tl(1) atoms. In the third S site, S(3) is bonded in a distorted pentagonal planar geometry to two equivalent Er(2), one Cu(1), one Cu(4), and one Cu(5) atom. In the fourth S site, S(4) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Er(3), one Cu(2), and one Cu(3) atom. In the fifth S site, S(5) is bonded in a 4-coordinate geometry to one Er(1), one Er(3), and two equivalent Cu(2) atoms. In the sixth S site, S(6) is bonded in a distorted pentagonal planar geometry to two equivalent Er(1), one Cu(2), one Cu(4), and one Cu(5) atom. In the seventh S site, S(7) is bonded in a 6-coordinate geometry to one Er(2), two equivalent Er(1), two equivalent Cu(4), and one Tl(2) atom. In the eighth S site, S(8) is bonded to one Er(1), two equivalent Er(2), two equivalent Cu(5), and one Tl(1) atom to form distorted edge-sharing SEr3TlCu2 octahedra. is represented by the CIF file [CIF]
data_Er3Tl2Cu5S8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.184
_cell_length_b   7.184
_cell_length_c   14.422
_cell_angle_alpha   69.582
_cell_angle_beta   69.582
_cell_angle_gamma   31.567
_symmetry_Int_Tables_number   1
_cell_volume   363.145
_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
  Er  Er0  1  0.037  0.037  0.592  1.0
  Er  Er1  1  0.334  0.334  0.827  1.0
  Er  Er2  1  0.197  0.197  0.213  1.0
  Tl  Tl3  1  1.000  1.000  1.000  1.0
  Tl  Tl4  1  0.372  0.372  0.414  1.0
  Cu  Cu5  1  0.718  0.718  0.018  1.0
  Cu  Cu6  1  0.657  0.657  0.407  1.0
  Cu  Cu7  1  0.979  0.979  0.209  1.0
  Cu  Cu8  1  0.787  0.787  0.662  1.0
  Cu  Cu9  1  0.586  0.586  0.757  1.0
  S  S10  1  0.575  0.575  0.169  1.0
  S  S11  1  0.312  0.312  0.017  1.0
  S  S12  1  0.695  0.695  0.850  1.0
  S  S13  1  0.804  0.804  0.258  1.0
  S  S14  1  0.062  0.062  0.402  1.0
  S  S15  1  0.675  0.675  0.571  1.0
  S  S16  1  0.386  0.386  0.627  1.0
  S  S17  1  0.985  0.985  0.792  1.0
[/CIF]
.
The material structure described by Er3Cu5Tl2S8 crystallizes in the monoclinic Cm space group. There are three inequivalent Er sites. In the first Er site, Er(1) is bonded to one S(5), one S(8), two equivalent S(6), and two equivalent S(7) atoms to form ErS6 octahedra that share  a cornercorner with one Er(3)S6 octahedra, corners with four equivalent Cu(4)S4 tetrahedra, edges with two equivalent Er(1)S6 octahedra, edges with two equivalent Er(2)S6 octahedra,  an edgeedge with one Cu(4)S4 tetrahedra, edges with two equivalent Cu(2)S4 tetrahedra, and edges with two equivalent Cu(5)S4 tetrahedra. The corner-sharing octahedral tilt angles are 33°. In the second Er site, Er(2) is bonded to one S(2), one S(7), two equivalent S(3), and two equivalent S(8) atoms to form ErS6 octahedra that share  a cornercorner with one Er(3)S6 octahedra, corners with four equivalent Cu(5)S4 tetrahedra, edges with two equivalent Er(1)S6 octahedra, edges with two equivalent Er(2)S6 octahedra,  an edgeedge with one Cu(5)S4 tetrahedra, edges with two equivalent Cu(1)S4 tetrahedra, and edges with two equivalent Cu(4)S4 tetrahedra. The corner-sharing octahedral tilt angles are 27°. In the third Er site, Er(3) is bonded to one S(2), one S(5), two equivalent S(1), and two equivalent S(4) atoms to form distorted ErS6 octahedra that share  a cornercorner with one Er(1)S6 octahedra,  a cornercorner with one Er(2)S6 octahedra, edges with two equivalent Er(3)S6 octahedra, edges with two equivalent Cu(1)S4 tetrahedra, and edges with two equivalent Cu(2)S4 tetrahedra. The corner-sharing octahedral tilt angles range from 27-33°. There are five inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one S(1), one S(3), and two equivalent S(2) atoms to form CuS4 tetrahedra that share  a cornercorner with one Cu(4)S4 tetrahedra,  a cornercorner with one Cu(5)S4 tetrahedra, corners with two equivalent Cu(1)S4 tetrahedra, edges with two equivalent Er(2)S6 octahedra, and edges with two equivalent Er(3)S6 octahedra. In the second Cu site, Cu(2) is bonded to one S(4), one S(6), and two equivalent S(5) atoms to form CuS4 tetrahedra that share  a cornercorner with one Cu(4)S4 tetrahedra,  a cornercorner with one Cu(5)S4 tetrahedra, corners with two equivalent Cu(2)S4 tetrahedra, edges with two equivalent Er(1)S6 octahedra, and edges with two equivalent Er(3)S6 octahedra. In the third Cu site, Cu(3) is bonded in a distorted trigonal planar geometry to one Tl(1), one S(4), and two equivalent S(1) atoms. In the fourth Cu site, Cu(4) is bonded to one S(3), one S(6), and two equivalent S(7) atoms to form distorted CuS4 tetrahedra that share corners with four equivalent Er(1)S6 octahedra,  a cornercorner with one Cu(1)S4 tetrahedra,  a cornercorner with one Cu(2)S4 tetrahedra, corners with two equivalent Cu(4)S4 tetrahedra,  an edgeedge with one Er(1)S6 octahedra, edges with two equivalent Er(2)S6 octahedra, and  an edgeedge with one Cu(5)S4 tetrahedra. The corner-sharing octahedral tilt angles range from 13-59°. In the fifth Cu site, Cu(5) is bonded to one S(3), one S(6), and two equivalent S(8) atoms to form distorted CuS4 tetrahedra that share corners with four equivalent Er(2)S6 octahedra,  a cornercorner with one Cu(1)S4 tetrahedra,  a cornercorner with one Cu(2)S4 tetrahedra, corners with two equivalent Cu(5)S4 tetrahedra,  an edgeedge with one Er(2)S6 octahedra, edges with two equivalent Er(1)S6 octahedra, and  an edgeedge with one Cu(4)S4 tetrahedra. The corner-sharing octahedral tilt angles range from 13-59°. There are two inequivalent Tl sites. In the first Tl site, Tl(1) is bonded in a 4-coordinate geometry to one Cu(3), one S(8), and two equivalent S(2) atoms. In the second Tl site, Tl(2) is bonded in a 1-coordinate geometry to one S(7) atom. There are eight inequivalent S sites. In the first S site, S(1) is bonded in a 5-coordinate geometry to two equivalent Er(3), one Cu(1), and two equivalent Cu(3) atoms. In the second S site, S(2) is bonded in a 4-coordinate geometry to one Er(2), one Er(3), two equivalent Cu(1), and two equivalent Tl(1) atoms. In the third S site, S(3) is bonded in a distorted pentagonal planar geometry to two equivalent Er(2), one Cu(1), one Cu(4), and one Cu(5) atom. In the fourth S site, S(4) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Er(3), one Cu(2), and one Cu(3) atom. In the fifth S site, S(5) is bonded in a 4-coordinate geometry to one Er(1), one Er(3), and two equivalent Cu(2) atoms. In the sixth S site, S(6) is bonded in a distorted pentagonal planar geometry to two equivalent Er(1), one Cu(2), one Cu(4), and one Cu(5) atom. In the seventh S site, S(7) is bonded in a 6-coordinate geometry to one Er(2), two equivalent Er(1), two equivalent Cu(4), and one Tl(2) atom. In the eighth S site, S(8) is bonded to one Er(1), two equivalent Er(2), two equivalent Cu(5), and one Tl(1) atom to form distorted edge-sharing SEr3TlCu2 octahedra. is represented by the CIF file [CIF]
data_Er3Tl2Cu5S8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.184
_cell_length_b   7.184
_cell_length_c   14.422
_cell_angle_alpha   69.582
_cell_angle_beta   69.582
_cell_angle_gamma   31.567
_symmetry_Int_Tables_number   1
_cell_volume   363.145
_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
  Er  Er0  1  0.037  0.037  0.592  1.0
  Er  Er1  1  0.334  0.334  0.827  1.0
  Er  Er2  1  0.197  0.197  0.213  1.0
  Tl  Tl3  1  1.000  1.000  1.000  1.0
  Tl  Tl4  1  0.372  0.372  0.414  1.0
  Cu  Cu5  1  0.718  0.718  0.018  1.0
  Cu  Cu6  1  0.657  0.657  0.407  1.0
  Cu  Cu7  1  0.979  0.979  0.209  1.0
  Cu  Cu8  1  0.787  0.787  0.662  1.0
  Cu  Cu9  1  0.586  0.586  0.757  1.0
  S  S10  1  0.575  0.575  0.169  1.0
  S  S11  1  0.312  0.312  0.017  1.0
  S  S12  1  0.695  0.695  0.850  1.0
  S  S13  1  0.804  0.804  0.258  1.0
  S  S14  1  0.062  0.062  0.402  1.0
  S  S15  1  0.675  0.675  0.571  1.0
  S  S16  1  0.386  0.386  0.627  1.0
  S  S17  1  0.985  0.985  0.792  1.0
[/CIF]
.