The material described by MgCu4(AsS)4 crystallizes in the triclinic P1 space group. Mg(1) is bonded in a 6-coordinate geometry to one Cu(3), one As(1), two equivalent S(1), and two equivalent S(4) atoms. There are four inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one As(2), one S(3), and two equivalent S(2) atoms to form CuAsS3 tetrahedra that share  a cornercorner with one As(4)CuAs2S tetrahedra, corners with two equivalent Cu(1)AsS3 tetrahedra, and corners with four equivalent Cu(2)AsS3 tetrahedra. In the second Cu site, Cu(2) is bonded to one As(1), one S(2), and two equivalent S(3) atoms to form CuAsS3 tetrahedra that share corners with two equivalent Cu(2)AsS3 tetrahedra, corners with four equivalent Cu(1)AsS3 tetrahedra, and corners with four equivalent As(4)CuAs2S tetrahedra. In the third Cu site, Cu(3) is bonded in a 5-coordinate geometry to one Mg(1), one As(3), one S(1), and two equivalent S(4) atoms. In the fourth Cu site, Cu(4) is bonded in a distorted trigonal non-coplanar geometry to one As(4) and two equivalent S(1) atoms. There are four inequivalent As sites. In the first As site, As(1) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Cu(2), and two equivalent As(4) atoms. In the second As site, As(2) is bonded in a distorted bent 120 degrees geometry to one Cu(1), two equivalent As(3), and one S(4) atom. In the third As site, As(3) is bonded in a distorted bent 120 degrees geometry to one Cu(3), two equivalent As(2), and one S(2) atom. In the fourth As site, As(4) is bonded to one Cu(4), two equivalent As(1), and one S(3) atom to form distorted AsCuAs2S tetrahedra that share  a cornercorner with one Cu(1)AsS3 tetrahedra, corners with two equivalent As(4)CuAs2S tetrahedra, corners with four equivalent Cu(2)AsS3 tetrahedra, and corners with two equivalent S(1)Mg2Cu3 trigonal bipyramids. There are four inequivalent S sites. In the first S site, S(1) is bonded to two equivalent Mg(1), one Cu(3), and two equivalent Cu(4) atoms to form distorted SMg2Cu3 trigonal bipyramids that share corners with two equivalent As(4)CuAs2S tetrahedra and corners with four equivalent S(1)Mg2Cu3 trigonal bipyramids. In the second S site, S(2) is bonded to one Cu(2), two equivalent Cu(1), and one As(3) atom to form corner-sharing SCu3As tetrahedra. In the third S site, S(3) is bonded to one Cu(1), two equivalent Cu(2), and one As(4) atom to form corner-sharing SCu3As tetrahedra. In the fourth S site, S(4) is bonded in a 5-coordinate geometry to two equivalent Mg(1), two equivalent Cu(3), and one As(2) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_MgCu4(AsS)4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.833
_cell_length_b   5.353
_cell_length_c   12.817
_cell_angle_alpha   98.404
_cell_angle_beta   90.037
_cell_angle_gamma   89.992
_symmetry_Int_Tables_number   1
_cell_volume   260.180
_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
  Mg  Mg0  1  0.780  0.408  0.807  1.0
  Cu  Cu1  1  0.282  0.430  0.330  1.0
  Cu  Cu2  1  0.780  0.865  0.182  1.0
  Cu  Cu3  1  0.780  0.674  0.637  1.0
  Cu  Cu4  1  0.281  0.940  0.882  1.0
  As  As5  1  0.779  0.550  0.026  1.0
  As  As6  1  0.278  0.202  0.480  1.0
  As  As7  1  0.778  0.895  0.493  1.0
  As  As8  1  0.280  0.246  0.035  1.0
  S  S9  1  0.781  0.929  0.796  1.0
  S  S10  1  0.781  0.664  0.329  1.0
  S  S11  1  0.280  0.106  0.196  1.0
  S  S12  1  0.280  0.425  0.651  1.0
[/CIF]
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The material described by MgCu4(AsS)4 crystallizes in the triclinic P1 space group. Mg(1) is bonded in a 6-coordinate geometry to one Cu(3), one As(1), two equivalent S(1), and two equivalent S(4) atoms. There are four inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one As(2), one S(3), and two equivalent S(2) atoms to form CuAsS3 tetrahedra that share  a cornercorner with one As(4)CuAs2S tetrahedra, corners with two equivalent Cu(1)AsS3 tetrahedra, and corners with four equivalent Cu(2)AsS3 tetrahedra. In the second Cu site, Cu(2) is bonded to one As(1), one S(2), and two equivalent S(3) atoms to form CuAsS3 tetrahedra that share corners with two equivalent Cu(2)AsS3 tetrahedra, corners with four equivalent Cu(1)AsS3 tetrahedra, and corners with four equivalent As(4)CuAs2S tetrahedra. In the third Cu site, Cu(3) is bonded in a 5-coordinate geometry to one Mg(1), one As(3), one S(1), and two equivalent S(4) atoms. In the fourth Cu site, Cu(4) is bonded in a distorted trigonal non-coplanar geometry to one As(4) and two equivalent S(1) atoms. There are four inequivalent As sites. In the first As site, As(1) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Cu(2), and two equivalent As(4) atoms. In the second As site, As(2) is bonded in a distorted bent 120 degrees geometry to one Cu(1), two equivalent As(3), and one S(4) atom. In the third As site, As(3) is bonded in a distorted bent 120 degrees geometry to one Cu(3), two equivalent As(2), and one S(2) atom. In the fourth As site, As(4) is bonded to one Cu(4), two equivalent As(1), and one S(3) atom to form distorted AsCuAs2S tetrahedra that share  a cornercorner with one Cu(1)AsS3 tetrahedra, corners with two equivalent As(4)CuAs2S tetrahedra, corners with four equivalent Cu(2)AsS3 tetrahedra, and corners with two equivalent S(1)Mg2Cu3 trigonal bipyramids. There are four inequivalent S sites. In the first S site, S(1) is bonded to two equivalent Mg(1), one Cu(3), and two equivalent Cu(4) atoms to form distorted SMg2Cu3 trigonal bipyramids that share corners with two equivalent As(4)CuAs2S tetrahedra and corners with four equivalent S(1)Mg2Cu3 trigonal bipyramids. In the second S site, S(2) is bonded to one Cu(2), two equivalent Cu(1), and one As(3) atom to form corner-sharing SCu3As tetrahedra. In the third S site, S(3) is bonded to one Cu(1), two equivalent Cu(2), and one As(4) atom to form corner-sharing SCu3As tetrahedra. In the fourth S site, S(4) is bonded in a 5-coordinate geometry to two equivalent Mg(1), two equivalent Cu(3), and one As(2) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_MgCu4(AsS)4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.833
_cell_length_b   5.353
_cell_length_c   12.817
_cell_angle_alpha   98.404
_cell_angle_beta   90.037
_cell_angle_gamma   89.992
_symmetry_Int_Tables_number   1
_cell_volume   260.180
_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
  Mg  Mg0  1  0.780  0.408  0.807  1.0
  Cu  Cu1  1  0.282  0.430  0.330  1.0
  Cu  Cu2  1  0.780  0.865  0.182  1.0
  Cu  Cu3  1  0.780  0.674  0.637  1.0
  Cu  Cu4  1  0.281  0.940  0.882  1.0
  As  As5  1  0.779  0.550  0.026  1.0
  As  As6  1  0.278  0.202  0.480  1.0
  As  As7  1  0.778  0.895  0.493  1.0
  As  As8  1  0.280  0.246  0.035  1.0
  S  S9  1  0.781  0.929  0.796  1.0
  S  S10  1  0.781  0.664  0.329  1.0
  S  S11  1  0.280  0.106  0.196  1.0
  S  S12  1  0.280  0.425  0.651  1.0
[/CIF]
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