The material described by MgYb2S4 crystallizes in the orthorhombic Pnma space group. Mg(1) is bonded to two equivalent S(4) and three equivalent S(1) atoms to form MgS5 square pyramids that share corners with two equivalent Yb(1)S6 octahedra, corners with four equivalent Yb(2)S5 trigonal bipyramids,  an edgeedge with one Yb(1)S6 octahedra, edges with four equivalent Mg(1)S5 square pyramids, and  an edgeedge with one Yb(2)S5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 23°. There are two inequivalent Yb sites. In the first Yb site, Yb(1) is bonded to one S(3), two equivalent S(4), and three equivalent S(2) atoms to form YbS6 octahedra that share corners with two equivalent Mg(1)S5 square pyramids,  a cornercorner with one S(4)Yb2Mg2S trigonal bipyramid, corners with five equivalent Yb(2)S5 trigonal bipyramids, edges with four equivalent Yb(1)S6 octahedra, and  an edgeedge with one Mg(1)S5 square pyramid. In the second Yb site, Yb(2) is bonded to one S(2), two equivalent S(1), and two equivalent S(3) atoms to form distorted YbS5 trigonal bipyramids that share corners with five equivalent Yb(1)S6 octahedra, corners with four equivalent Mg(1)S5 square pyramids, corners with two equivalent S(4)Yb2Mg2S trigonal bipyramids,  an edgeedge with one Mg(1)S5 square pyramid, and edges with two equivalent Yb(2)S5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 52-82°. There are four inequivalent S sites. In the first S site, S(1) is bonded to three equivalent Mg(1) and two equivalent Yb(2) atoms to form SYb2Mg3 trigonal bipyramids that share corners with four equivalent S(4)Yb2Mg2S trigonal bipyramids, corners with two equivalent S(2)Yb4 trigonal pyramids,  an edgeedge with one S(4)Yb2Mg2S trigonal bipyramid, and edges with four equivalent S(1)Yb2Mg3 trigonal bipyramids. In the second S site, S(2) is bonded to one Yb(2) and three equivalent Yb(1) atoms to form SYb4 trigonal pyramids that share corners with two equivalent S(1)Yb2Mg3 trigonal bipyramids, corners with four equivalent S(4)Yb2Mg2S trigonal bipyramids, corners with two equivalent S(2)Yb4 trigonal pyramids,  an edgeedge with one S(4)Yb2Mg2S trigonal bipyramid, and edges with two equivalent S(2)Yb4 trigonal pyramids. In the third S site, S(3) is bonded in a distorted rectangular see-saw-like geometry to one Yb(1), two equivalent Yb(2), and one S(4) atom. In the fourth S site, S(4) is bonded to two equivalent Mg(1), two equivalent Yb(1), and one S(3) atom to form distorted SYb2Mg2S trigonal bipyramids that share  a cornercorner with one Yb(1)S6 octahedra, corners with two equivalent Yb(2)S5 trigonal bipyramids, corners with four equivalent S(1)Yb2Mg3 trigonal bipyramids, corners with four equivalent S(2)Yb4 trigonal pyramids,  an edgeedge with one S(1)Yb2Mg3 trigonal bipyramid, edges with two equivalent S(4)Yb2Mg2S trigonal bipyramids, and  an edgeedge with one S(2)Yb4 trigonal pyramid. The corner-sharing octahedral tilt angles are 34°. is represented by the Crystallographic Information File (CIF) [CIF]
data_Yb2MgS4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.953
_cell_length_b   12.759
_cell_length_c   13.571
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   684.421
_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  0.250  0.055  0.114  1.0
  Yb  Yb1  1  0.750  0.945  0.886  1.0
  Yb  Yb2  1  0.750  0.555  0.386  1.0
  Yb  Yb3  1  0.250  0.445  0.614  1.0
  Yb  Yb4  1  0.250  0.728  0.123  1.0
  Yb  Yb5  1  0.750  0.272  0.877  1.0
  Yb  Yb6  1  0.750  0.228  0.377  1.0
  Yb  Yb7  1  0.250  0.772  0.623  1.0
  Mg  Mg8  1  0.750  0.437  0.089  1.0
  Mg  Mg9  1  0.250  0.563  0.911  1.0
  Mg  Mg10  1  0.250  0.937  0.411  1.0
  Mg  Mg11  1  0.750  0.063  0.589  1.0
  S  S12  1  0.750  0.618  0.026  1.0
  S  S13  1  0.250  0.382  0.974  1.0
  S  S14  1  0.250  0.118  0.474  1.0
  S  S15  1  0.750  0.882  0.526  1.0
  S  S16  1  0.250  0.882  0.999  1.0
  S  S17  1  0.750  0.118  0.001  1.0
  S  S18  1  0.750  0.382  0.501  1.0
  S  S19  1  0.250  0.618  0.499  1.0
  S  S20  1  0.250  0.279  0.237  1.0
  S  S21  1  0.750  0.721  0.763  1.0
  S  S22  1  0.750  0.779  0.263  1.0
  S  S23  1  0.250  0.221  0.737  1.0
  S  S24  1  0.750  0.946  0.273  1.0
  S  S25  1  0.250  0.054  0.727  1.0
  S  S26  1  0.250  0.446  0.227  1.0
  S  S27  1  0.750  0.554  0.773  1.0
[/CIF]
.
The material described by MgYb2S4 crystallizes in the orthorhombic Pnma space group. Mg(1) is bonded to two equivalent S(4) and three equivalent S(1) atoms to form MgS5 square pyramids that share corners with two equivalent Yb(1)S6 octahedra, corners with four equivalent Yb(2)S5 trigonal bipyramids,  an edgeedge with one Yb(1)S6 octahedra, edges with four equivalent Mg(1)S5 square pyramids, and  an edgeedge with one Yb(2)S5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 23°. There are two inequivalent Yb sites. In the first Yb site, Yb(1) is bonded to one S(3), two equivalent S(4), and three equivalent S(2) atoms to form YbS6 octahedra that share corners with two equivalent Mg(1)S5 square pyramids,  a cornercorner with one S(4)Yb2Mg2S trigonal bipyramid, corners with five equivalent Yb(2)S5 trigonal bipyramids, edges with four equivalent Yb(1)S6 octahedra, and  an edgeedge with one Mg(1)S5 square pyramid. In the second Yb site, Yb(2) is bonded to one S(2), two equivalent S(1), and two equivalent S(3) atoms to form distorted YbS5 trigonal bipyramids that share corners with five equivalent Yb(1)S6 octahedra, corners with four equivalent Mg(1)S5 square pyramids, corners with two equivalent S(4)Yb2Mg2S trigonal bipyramids,  an edgeedge with one Mg(1)S5 square pyramid, and edges with two equivalent Yb(2)S5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 52-82°. There are four inequivalent S sites. In the first S site, S(1) is bonded to three equivalent Mg(1) and two equivalent Yb(2) atoms to form SYb2Mg3 trigonal bipyramids that share corners with four equivalent S(4)Yb2Mg2S trigonal bipyramids, corners with two equivalent S(2)Yb4 trigonal pyramids,  an edgeedge with one S(4)Yb2Mg2S trigonal bipyramid, and edges with four equivalent S(1)Yb2Mg3 trigonal bipyramids. In the second S site, S(2) is bonded to one Yb(2) and three equivalent Yb(1) atoms to form SYb4 trigonal pyramids that share corners with two equivalent S(1)Yb2Mg3 trigonal bipyramids, corners with four equivalent S(4)Yb2Mg2S trigonal bipyramids, corners with two equivalent S(2)Yb4 trigonal pyramids,  an edgeedge with one S(4)Yb2Mg2S trigonal bipyramid, and edges with two equivalent S(2)Yb4 trigonal pyramids. In the third S site, S(3) is bonded in a distorted rectangular see-saw-like geometry to one Yb(1), two equivalent Yb(2), and one S(4) atom. In the fourth S site, S(4) is bonded to two equivalent Mg(1), two equivalent Yb(1), and one S(3) atom to form distorted SYb2Mg2S trigonal bipyramids that share  a cornercorner with one Yb(1)S6 octahedra, corners with two equivalent Yb(2)S5 trigonal bipyramids, corners with four equivalent S(1)Yb2Mg3 trigonal bipyramids, corners with four equivalent S(2)Yb4 trigonal pyramids,  an edgeedge with one S(1)Yb2Mg3 trigonal bipyramid, edges with two equivalent S(4)Yb2Mg2S trigonal bipyramids, and  an edgeedge with one S(2)Yb4 trigonal pyramid. The corner-sharing octahedral tilt angles are 34°. is represented by the Crystallographic Information File (CIF) [CIF]
data_Yb2MgS4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.953
_cell_length_b   12.759
_cell_length_c   13.571
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   684.421
_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  0.250  0.055  0.114  1.0
  Yb  Yb1  1  0.750  0.945  0.886  1.0
  Yb  Yb2  1  0.750  0.555  0.386  1.0
  Yb  Yb3  1  0.250  0.445  0.614  1.0
  Yb  Yb4  1  0.250  0.728  0.123  1.0
  Yb  Yb5  1  0.750  0.272  0.877  1.0
  Yb  Yb6  1  0.750  0.228  0.377  1.0
  Yb  Yb7  1  0.250  0.772  0.623  1.0
  Mg  Mg8  1  0.750  0.437  0.089  1.0
  Mg  Mg9  1  0.250  0.563  0.911  1.0
  Mg  Mg10  1  0.250  0.937  0.411  1.0
  Mg  Mg11  1  0.750  0.063  0.589  1.0
  S  S12  1  0.750  0.618  0.026  1.0
  S  S13  1  0.250  0.382  0.974  1.0
  S  S14  1  0.250  0.118  0.474  1.0
  S  S15  1  0.750  0.882  0.526  1.0
  S  S16  1  0.250  0.882  0.999  1.0
  S  S17  1  0.750  0.118  0.001  1.0
  S  S18  1  0.750  0.382  0.501  1.0
  S  S19  1  0.250  0.618  0.499  1.0
  S  S20  1  0.250  0.279  0.237  1.0
  S  S21  1  0.750  0.721  0.763  1.0
  S  S22  1  0.750  0.779  0.263  1.0
  S  S23  1  0.250  0.221  0.737  1.0
  S  S24  1  0.750  0.946  0.273  1.0
  S  S25  1  0.250  0.054  0.727  1.0
  S  S26  1  0.250  0.446  0.227  1.0
  S  S27  1  0.750  0.554  0.773  1.0
[/CIF]
.