The crystal structure described by MgYb2S4 crystallizes in the triclinic P-1 space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to one S(2), one S(3), one S(4), one S(5), and one S(6) atom to form MgS5 trigonal bipyramids that share corners with two equivalent Yb(3)S5 trigonal bipyramids, corners with two equivalent Yb(4)S5 trigonal bipyramids, edges with two equivalent Yb(2)S8 hexagonal bipyramids,  an edgeedge with one Yb(3)S5 trigonal bipyramid, and  an edgeedge with one Yb(4)S5 trigonal bipyramid. In the second Mg site, Mg(2) is bonded in a 5-coordinate geometry to one S(1), one S(2), one S(6), one S(7), and one S(8) atom. There are four inequivalent Yb sites. In the first Yb site, Yb(1) is bonded in a distorted hexagonal planar geometry to one S(3), one S(4), one S(5), one S(6), and two equivalent S(1) atoms. In the second Yb site, Yb(2) is bonded to one S(1), one S(3), one S(5), one S(8), two equivalent S(2), and two equivalent S(7) atoms to form distorted YbS8 hexagonal bipyramids that share  a cornercorner with one Yb(4)S5 trigonal bipyramid, edges with two equivalent Yb(2)S8 hexagonal bipyramids,  an edgeedge with one Yb(3)S5 trigonal bipyramid, edges with two equivalent Mg(1)S5 trigonal bipyramids, and edges with two equivalent Yb(4)S5 trigonal bipyramids. In the third Yb site, Yb(3) is bonded to one S(3), one S(4), one S(8), and two equivalent S(6) atoms to form YbS5 trigonal bipyramids that share corners with two equivalent Mg(1)S5 trigonal bipyramids, corners with two equivalent Yb(4)S5 trigonal bipyramids,  an edgeedge with one Yb(2)S8 hexagonal bipyramid,  an edgeedge with one Mg(1)S5 trigonal bipyramid, and  an edgeedge with one Yb(3)S5 trigonal bipyramid. In the fourth Yb site, Yb(4) is bonded to one S(3), one S(4), one S(7), and two equivalent S(5) atoms to form YbS5 trigonal bipyramids that share  a cornercorner with one Yb(2)S8 hexagonal bipyramid, corners with two equivalent Mg(1)S5 trigonal bipyramids, corners with two equivalent Yb(3)S5 trigonal bipyramids, edges with two equivalent Yb(2)S8 hexagonal bipyramids,  an edgeedge with one Mg(1)S5 trigonal bipyramid, and  an edgeedge with one Yb(4)S5 trigonal bipyramid. There are eight inequivalent S sites. In the first S site, S(1) is bonded in a 5-coordinate geometry to one Mg(2), one Yb(2), two equivalent Yb(1), and one S(1) atom. In the second S site, S(2) is bonded in a 5-coordinate geometry to one Mg(1), one Mg(2), two equivalent Yb(2), and one S(2) atom. In the third S site, S(3) is bonded to one Mg(1), one Yb(1), one Yb(2), one Yb(3), and one Yb(4) atom to form SYb4Mg trigonal bipyramids that share corners with two equivalent S(6)Yb3Mg2 trigonal bipyramids, corners with three equivalent S(5)Yb4Mg trigonal bipyramids, corners with two equivalent S(4)Yb3Mg trigonal pyramids,  an edgeedge with one S(6)Yb3Mg2 trigonal bipyramid,  an edgeedge with one S(5)Yb4Mg trigonal bipyramid, and  an edgeedge with one S(4)Yb3Mg trigonal pyramid. In the fourth S site, S(4) is bonded to one Mg(1), one Yb(1), one Yb(3), and one Yb(4) atom to form SYb3Mg trigonal pyramids that share corners with two equivalent S(6)Yb3Mg2 trigonal bipyramids, corners with two equivalent S(3)Yb4Mg trigonal bipyramids, corners with two equivalent S(5)Yb4Mg trigonal bipyramids,  an edgeedge with one S(6)Yb3Mg2 trigonal bipyramid,  an edgeedge with one S(3)Yb4Mg trigonal bipyramid, and  an edgeedge with one S(5)Yb4Mg trigonal bipyramid. In the fifth S site, S(5) is bonded to one Mg(1), one Yb(1), one Yb(2), and two equivalent Yb(4) atoms to form SYb4Mg trigonal bipyramids that share corners with two equivalent S(6)Yb3Mg2 trigonal bipyramids, corners with three equivalent S(3)Yb4Mg trigonal bipyramids, corners with two equivalent S(4)Yb3Mg trigonal pyramids,  an edgeedge with one S(3)Yb4Mg trigonal bipyramid,  an edgeedge with one S(5)Yb4Mg trigonal bipyramid, and  an edgeedge with one S(4)Yb3Mg trigonal pyramid. In the sixth S site, S(6) is bonded to one Mg(1), one Mg(2), one Yb(1), and two equivalent Yb(3) atoms to form SYb3Mg2 trigonal bipyramids that share corners with two equivalent S(3)Yb4Mg trigonal bipyramids, corners with two equivalent S(5)Yb4Mg trigonal bipyramids, corners with two equivalent S(4)Yb3Mg trigonal pyramids,  an edgeedge with one S(6)Yb3Mg2 trigonal bipyramid,  an edgeedge with one S(3)Yb4Mg trigonal bipyramid, and  an edgeedge with one S(4)Yb3Mg trigonal pyramid. In the seventh S site, S(7) is bonded in a 5-coordinate geometry to one Mg(2), one Yb(4), two equivalent Yb(2), and one S(8) atom. In the eighth S site, S(8) is bonded in a 5-coordinate geometry to one Mg(2), one Yb(2), one Yb(3), one S(7), and one S(8) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Yb2MgS4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.581
_cell_length_b   9.120
_cell_length_c   9.514
_cell_angle_alpha   71.559
_cell_angle_beta   78.090
_cell_angle_gamma   96.040
_symmetry_Int_Tables_number   1
_cell_volume   679.385
_cell_formula_units_Z   4
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
  Yb  Yb0  1  0.105  0.662  0.680  1.0
  Yb  Yb1  1  0.895  0.338  0.320  1.0
  Yb  Yb2  1  0.252  0.854  0.993  1.0
  Yb  Yb3  1  0.748  0.146  0.007  1.0
  Yb  Yb4  1  0.367  0.541  0.347  1.0
  Yb  Yb5  1  0.633  0.459  0.653  1.0
  Yb  Yb6  1  0.367  0.035  0.361  1.0
  Yb  Yb7  1  0.633  0.965  0.639  1.0
  Mg  Mg8  1  0.118  0.181  0.631  1.0
  Mg  Mg9  1  0.882  0.819  0.369  1.0
  Mg  Mg10  1  0.248  0.325  0.951  1.0
  Mg  Mg11  1  0.752  0.675  0.049  1.0
  S  S12  1  0.117  0.534  0.015  1.0
  S  S13  1  0.883  0.466  0.985  1.0
  S  S14  1  0.063  0.110  0.920  1.0
  S  S15  1  0.937  0.890  0.080  1.0
  S  S16  1  0.184  0.771  0.348  1.0
  S  S17  1  0.816  0.229  0.652  1.0
  S  S18  1  0.193  0.269  0.352  1.0
  S  S19  1  0.807  0.731  0.648  1.0
  S  S20  1  0.289  0.939  0.675  1.0
  S  S21  1  0.711  0.061  0.325  1.0
  S  S22  1  0.291  0.418  0.667  1.0
  S  S23  1  0.709  0.582  0.333  1.0
  S  S24  1  0.419  0.123  0.048  1.0
  S  S25  1  0.581  0.877  0.952  1.0
  S  S26  1  0.474  0.635  0.020  1.0
  S  S27  1  0.526  0.365  0.980  1.0
[/CIF]
.
The crystal structure described by MgYb2S4 crystallizes in the triclinic P-1 space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to one S(2), one S(3), one S(4), one S(5), and one S(6) atom to form MgS5 trigonal bipyramids that share corners with two equivalent Yb(3)S5 trigonal bipyramids, corners with two equivalent Yb(4)S5 trigonal bipyramids, edges with two equivalent Yb(2)S8 hexagonal bipyramids,  an edgeedge with one Yb(3)S5 trigonal bipyramid, and  an edgeedge with one Yb(4)S5 trigonal bipyramid. In the second Mg site, Mg(2) is bonded in a 5-coordinate geometry to one S(1), one S(2), one S(6), one S(7), and one S(8) atom. There are four inequivalent Yb sites. In the first Yb site, Yb(1) is bonded in a distorted hexagonal planar geometry to one S(3), one S(4), one S(5), one S(6), and two equivalent S(1) atoms. In the second Yb site, Yb(2) is bonded to one S(1), one S(3), one S(5), one S(8), two equivalent S(2), and two equivalent S(7) atoms to form distorted YbS8 hexagonal bipyramids that share  a cornercorner with one Yb(4)S5 trigonal bipyramid, edges with two equivalent Yb(2)S8 hexagonal bipyramids,  an edgeedge with one Yb(3)S5 trigonal bipyramid, edges with two equivalent Mg(1)S5 trigonal bipyramids, and edges with two equivalent Yb(4)S5 trigonal bipyramids. In the third Yb site, Yb(3) is bonded to one S(3), one S(4), one S(8), and two equivalent S(6) atoms to form YbS5 trigonal bipyramids that share corners with two equivalent Mg(1)S5 trigonal bipyramids, corners with two equivalent Yb(4)S5 trigonal bipyramids,  an edgeedge with one Yb(2)S8 hexagonal bipyramid,  an edgeedge with one Mg(1)S5 trigonal bipyramid, and  an edgeedge with one Yb(3)S5 trigonal bipyramid. In the fourth Yb site, Yb(4) is bonded to one S(3), one S(4), one S(7), and two equivalent S(5) atoms to form YbS5 trigonal bipyramids that share  a cornercorner with one Yb(2)S8 hexagonal bipyramid, corners with two equivalent Mg(1)S5 trigonal bipyramids, corners with two equivalent Yb(3)S5 trigonal bipyramids, edges with two equivalent Yb(2)S8 hexagonal bipyramids,  an edgeedge with one Mg(1)S5 trigonal bipyramid, and  an edgeedge with one Yb(4)S5 trigonal bipyramid. There are eight inequivalent S sites. In the first S site, S(1) is bonded in a 5-coordinate geometry to one Mg(2), one Yb(2), two equivalent Yb(1), and one S(1) atom. In the second S site, S(2) is bonded in a 5-coordinate geometry to one Mg(1), one Mg(2), two equivalent Yb(2), and one S(2) atom. In the third S site, S(3) is bonded to one Mg(1), one Yb(1), one Yb(2), one Yb(3), and one Yb(4) atom to form SYb4Mg trigonal bipyramids that share corners with two equivalent S(6)Yb3Mg2 trigonal bipyramids, corners with three equivalent S(5)Yb4Mg trigonal bipyramids, corners with two equivalent S(4)Yb3Mg trigonal pyramids,  an edgeedge with one S(6)Yb3Mg2 trigonal bipyramid,  an edgeedge with one S(5)Yb4Mg trigonal bipyramid, and  an edgeedge with one S(4)Yb3Mg trigonal pyramid. In the fourth S site, S(4) is bonded to one Mg(1), one Yb(1), one Yb(3), and one Yb(4) atom to form SYb3Mg trigonal pyramids that share corners with two equivalent S(6)Yb3Mg2 trigonal bipyramids, corners with two equivalent S(3)Yb4Mg trigonal bipyramids, corners with two equivalent S(5)Yb4Mg trigonal bipyramids,  an edgeedge with one S(6)Yb3Mg2 trigonal bipyramid,  an edgeedge with one S(3)Yb4Mg trigonal bipyramid, and  an edgeedge with one S(5)Yb4Mg trigonal bipyramid. In the fifth S site, S(5) is bonded to one Mg(1), one Yb(1), one Yb(2), and two equivalent Yb(4) atoms to form SYb4Mg trigonal bipyramids that share corners with two equivalent S(6)Yb3Mg2 trigonal bipyramids, corners with three equivalent S(3)Yb4Mg trigonal bipyramids, corners with two equivalent S(4)Yb3Mg trigonal pyramids,  an edgeedge with one S(3)Yb4Mg trigonal bipyramid,  an edgeedge with one S(5)Yb4Mg trigonal bipyramid, and  an edgeedge with one S(4)Yb3Mg trigonal pyramid. In the sixth S site, S(6) is bonded to one Mg(1), one Mg(2), one Yb(1), and two equivalent Yb(3) atoms to form SYb3Mg2 trigonal bipyramids that share corners with two equivalent S(3)Yb4Mg trigonal bipyramids, corners with two equivalent S(5)Yb4Mg trigonal bipyramids, corners with two equivalent S(4)Yb3Mg trigonal pyramids,  an edgeedge with one S(6)Yb3Mg2 trigonal bipyramid,  an edgeedge with one S(3)Yb4Mg trigonal bipyramid, and  an edgeedge with one S(4)Yb3Mg trigonal pyramid. In the seventh S site, S(7) is bonded in a 5-coordinate geometry to one Mg(2), one Yb(4), two equivalent Yb(2), and one S(8) atom. In the eighth S site, S(8) is bonded in a 5-coordinate geometry to one Mg(2), one Yb(2), one Yb(3), one S(7), and one S(8) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Yb2MgS4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.581
_cell_length_b   9.120
_cell_length_c   9.514
_cell_angle_alpha   71.559
_cell_angle_beta   78.090
_cell_angle_gamma   96.040
_symmetry_Int_Tables_number   1
_cell_volume   679.385
_cell_formula_units_Z   4
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
  Yb  Yb0  1  0.105  0.662  0.680  1.0
  Yb  Yb1  1  0.895  0.338  0.320  1.0
  Yb  Yb2  1  0.252  0.854  0.993  1.0
  Yb  Yb3  1  0.748  0.146  0.007  1.0
  Yb  Yb4  1  0.367  0.541  0.347  1.0
  Yb  Yb5  1  0.633  0.459  0.653  1.0
  Yb  Yb6  1  0.367  0.035  0.361  1.0
  Yb  Yb7  1  0.633  0.965  0.639  1.0
  Mg  Mg8  1  0.118  0.181  0.631  1.0
  Mg  Mg9  1  0.882  0.819  0.369  1.0
  Mg  Mg10  1  0.248  0.325  0.951  1.0
  Mg  Mg11  1  0.752  0.675  0.049  1.0
  S  S12  1  0.117  0.534  0.015  1.0
  S  S13  1  0.883  0.466  0.985  1.0
  S  S14  1  0.063  0.110  0.920  1.0
  S  S15  1  0.937  0.890  0.080  1.0
  S  S16  1  0.184  0.771  0.348  1.0
  S  S17  1  0.816  0.229  0.652  1.0
  S  S18  1  0.193  0.269  0.352  1.0
  S  S19  1  0.807  0.731  0.648  1.0
  S  S20  1  0.289  0.939  0.675  1.0
  S  S21  1  0.711  0.061  0.325  1.0
  S  S22  1  0.291  0.418  0.667  1.0
  S  S23  1  0.709  0.582  0.333  1.0
  S  S24  1  0.419  0.123  0.048  1.0
  S  S25  1  0.581  0.877  0.952  1.0
  S  S26  1  0.474  0.635  0.020  1.0
  S  S27  1  0.526  0.365  0.980  1.0
[/CIF]
.