The structure described by MgPr2S4 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 Pr(1)S6 octahedra, corners with two equivalent Pr(2)S6 octahedra,  an edgeedge with one Pr(1)S6 octahedra, edges with three equivalent Pr(2)S6 octahedra, and edges with four equivalent Mg(1)S5 square pyramids. The corner-sharing octahedral tilt angles range from 5-6°. There are two inequivalent Pr sites. In the first Pr site, Pr(1) is bonded to one S(3), two equivalent S(4), and three equivalent S(2) atoms to form PrS6 octahedra that share corners with three equivalent Pr(2)S6 octahedra, corners with two equivalent Mg(1)S5 square pyramids, edges with two equivalent Pr(2)S6 octahedra, edges with four equivalent Pr(1)S6 octahedra, and  an edgeedge with one Mg(1)S5 square pyramid. The corner-sharing octahedral tilt angles range from 54-60°. In the second Pr site, Pr(2) is bonded to one S(2), one S(4), two equivalent S(1), and two equivalent S(3) atoms to form PrS6 octahedra that share corners with three equivalent Pr(1)S6 octahedra, corners with two equivalent Mg(1)S5 square pyramids, edges with two equivalent Pr(1)S6 octahedra, edges with two equivalent Pr(2)S6 octahedra, and edges with three equivalent Mg(1)S5 square pyramids. The corner-sharing octahedral tilt angles range from 54-60°. There are four inequivalent S sites. In the first S site, S(1) is bonded to three equivalent Mg(1) and two equivalent Pr(2) atoms to form SPr2Mg3 square pyramids that share corners with two equivalent S(4)Pr3Mg2 square pyramids, edges with three equivalent S(4)Pr3Mg2 square pyramids, and edges with four equivalent S(1)Pr2Mg3 square pyramids. In the second S site, S(2) is bonded in a rectangular see-saw-like geometry to one Pr(2) and three equivalent Pr(1) atoms. In the third S site, S(3) is bonded in a distorted trigonal non-coplanar geometry to one Pr(1) and two equivalent Pr(2) atoms. In the fourth S site, S(4) is bonded to two equivalent Mg(1), one Pr(2), and two equivalent Pr(1) atoms to form SPr3Mg2 square pyramids that share corners with two equivalent S(1)Pr2Mg3 square pyramids, edges with two equivalent S(4)Pr3Mg2 square pyramids, and edges with three equivalent S(1)Pr2Mg3 square pyramids. is represented by the Crystallographic Information File (CIF) [CIF]
data_Pr2MgS4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.994
_cell_length_b   13.042
_cell_length_c   14.180
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   738.642
_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
  Pr  Pr0  1  0.250  0.123  0.074  1.0
  Pr  Pr1  1  0.750  0.877  0.926  1.0
  Pr  Pr2  1  0.750  0.377  0.574  1.0
  Pr  Pr3  1  0.250  0.623  0.426  1.0
  Pr  Pr4  1  0.250  0.130  0.709  1.0
  Pr  Pr5  1  0.750  0.870  0.291  1.0
  Pr  Pr6  1  0.750  0.370  0.209  1.0
  Pr  Pr7  1  0.250  0.630  0.791  1.0
  Mg  Mg8  1  0.750  0.105  0.465  1.0
  Mg  Mg9  1  0.250  0.895  0.535  1.0
  Mg  Mg10  1  0.250  0.395  0.965  1.0
  Mg  Mg11  1  0.750  0.605  0.035  1.0
  S  S12  1  0.750  1.000  0.613  1.0
  S  S13  1  0.250  0.000  0.387  1.0
  S  S14  1  0.250  0.500  0.113  1.0
  S  S15  1  0.750  0.500  0.887  1.0
  S  S16  1  0.250  0.024  0.887  1.0
  S  S17  1  0.750  0.976  0.113  1.0
  S  S18  1  0.750  0.476  0.387  1.0
  S  S19  1  0.250  0.524  0.613  1.0
  S  S20  1  0.250  0.232  0.244  1.0
  S  S21  1  0.750  0.768  0.756  1.0
  S  S22  1  0.750  0.268  0.744  1.0
  S  S23  1  0.250  0.732  0.256  1.0
  S  S24  1  0.750  0.272  0.017  1.0
  S  S25  1  0.250  0.728  0.983  1.0
  S  S26  1  0.250  0.228  0.517  1.0
  S  S27  1  0.750  0.772  0.483  1.0
[/CIF]
.
The structure described by MgPr2S4 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 Pr(1)S6 octahedra, corners with two equivalent Pr(2)S6 octahedra,  an edgeedge with one Pr(1)S6 octahedra, edges with three equivalent Pr(2)S6 octahedra, and edges with four equivalent Mg(1)S5 square pyramids. The corner-sharing octahedral tilt angles range from 5-6°. There are two inequivalent Pr sites. In the first Pr site, Pr(1) is bonded to one S(3), two equivalent S(4), and three equivalent S(2) atoms to form PrS6 octahedra that share corners with three equivalent Pr(2)S6 octahedra, corners with two equivalent Mg(1)S5 square pyramids, edges with two equivalent Pr(2)S6 octahedra, edges with four equivalent Pr(1)S6 octahedra, and  an edgeedge with one Mg(1)S5 square pyramid. The corner-sharing octahedral tilt angles range from 54-60°. In the second Pr site, Pr(2) is bonded to one S(2), one S(4), two equivalent S(1), and two equivalent S(3) atoms to form PrS6 octahedra that share corners with three equivalent Pr(1)S6 octahedra, corners with two equivalent Mg(1)S5 square pyramids, edges with two equivalent Pr(1)S6 octahedra, edges with two equivalent Pr(2)S6 octahedra, and edges with three equivalent Mg(1)S5 square pyramids. The corner-sharing octahedral tilt angles range from 54-60°. There are four inequivalent S sites. In the first S site, S(1) is bonded to three equivalent Mg(1) and two equivalent Pr(2) atoms to form SPr2Mg3 square pyramids that share corners with two equivalent S(4)Pr3Mg2 square pyramids, edges with three equivalent S(4)Pr3Mg2 square pyramids, and edges with four equivalent S(1)Pr2Mg3 square pyramids. In the second S site, S(2) is bonded in a rectangular see-saw-like geometry to one Pr(2) and three equivalent Pr(1) atoms. In the third S site, S(3) is bonded in a distorted trigonal non-coplanar geometry to one Pr(1) and two equivalent Pr(2) atoms. In the fourth S site, S(4) is bonded to two equivalent Mg(1), one Pr(2), and two equivalent Pr(1) atoms to form SPr3Mg2 square pyramids that share corners with two equivalent S(1)Pr2Mg3 square pyramids, edges with two equivalent S(4)Pr3Mg2 square pyramids, and edges with three equivalent S(1)Pr2Mg3 square pyramids. is represented by the Crystallographic Information File (CIF) [CIF]
data_Pr2MgS4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.994
_cell_length_b   13.042
_cell_length_c   14.180
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   738.642
_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
  Pr  Pr0  1  0.250  0.123  0.074  1.0
  Pr  Pr1  1  0.750  0.877  0.926  1.0
  Pr  Pr2  1  0.750  0.377  0.574  1.0
  Pr  Pr3  1  0.250  0.623  0.426  1.0
  Pr  Pr4  1  0.250  0.130  0.709  1.0
  Pr  Pr5  1  0.750  0.870  0.291  1.0
  Pr  Pr6  1  0.750  0.370  0.209  1.0
  Pr  Pr7  1  0.250  0.630  0.791  1.0
  Mg  Mg8  1  0.750  0.105  0.465  1.0
  Mg  Mg9  1  0.250  0.895  0.535  1.0
  Mg  Mg10  1  0.250  0.395  0.965  1.0
  Mg  Mg11  1  0.750  0.605  0.035  1.0
  S  S12  1  0.750  1.000  0.613  1.0
  S  S13  1  0.250  0.000  0.387  1.0
  S  S14  1  0.250  0.500  0.113  1.0
  S  S15  1  0.750  0.500  0.887  1.0
  S  S16  1  0.250  0.024  0.887  1.0
  S  S17  1  0.750  0.976  0.113  1.0
  S  S18  1  0.750  0.476  0.387  1.0
  S  S19  1  0.250  0.524  0.613  1.0
  S  S20  1  0.250  0.232  0.244  1.0
  S  S21  1  0.750  0.768  0.756  1.0
  S  S22  1  0.750  0.268  0.744  1.0
  S  S23  1  0.250  0.732  0.256  1.0
  S  S24  1  0.750  0.272  0.017  1.0
  S  S25  1  0.250  0.728  0.983  1.0
  S  S26  1  0.250  0.228  0.517  1.0
  S  S27  1  0.750  0.772  0.483  1.0
[/CIF]
.