The crystal structure described by MgPm2S4 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 Pm(1)S6 octahedra, corners with two equivalent Pm(2)S6 octahedra,  an edgeedge with one Pm(1)S6 octahedra, edges with three equivalent Pm(2)S6 octahedra, and edges with four equivalent Mg(1)S5 square pyramids. The corner-sharing octahedral tilt angles are 5°. There are two inequivalent Pm sites. In the first Pm site, Pm(1) is bonded to one S(3), two equivalent S(4), and three equivalent S(2) atoms to form PmS6 octahedra that share corners with three equivalent Pm(2)S6 octahedra, corners with two equivalent Mg(1)S5 square pyramids, edges with two equivalent Pm(2)S6 octahedra, edges with four equivalent Pm(1)S6 octahedra, and  an edgeedge with one Mg(1)S5 square pyramid. The corner-sharing octahedral tilt angles range from 55-59°. In the second Pm site, Pm(2) is bonded to one S(2), one S(4), two equivalent S(1), and two equivalent S(3) atoms to form PmS6 octahedra that share corners with three equivalent Pm(1)S6 octahedra, corners with two equivalent Mg(1)S5 square pyramids, edges with two equivalent Pm(1)S6 octahedra, edges with two equivalent Pm(2)S6 octahedra, and edges with three equivalent Mg(1)S5 square pyramids. The corner-sharing octahedral tilt angles range from 55-59°. There are four inequivalent S sites. In the first S site, S(1) is bonded to three equivalent Mg(1) and two equivalent Pm(2) atoms to form SPm2Mg3 square pyramids that share corners with two equivalent S(4)Pm3Mg2 square pyramids, edges with three equivalent S(4)Pm3Mg2 square pyramids, and edges with four equivalent S(1)Pm2Mg3 square pyramids. In the second S site, S(2) is bonded in a rectangular see-saw-like geometry to one Pm(2) and three equivalent Pm(1) atoms. In the third S site, S(3) is bonded in a distorted trigonal non-coplanar geometry to one Pm(1) and two equivalent Pm(2) atoms. In the fourth S site, S(4) is bonded to two equivalent Mg(1), one Pm(2), and two equivalent Pm(1) atoms to form SPm3Mg2 square pyramids that share corners with two equivalent S(1)Pm2Mg3 square pyramids, edges with two equivalent S(4)Pm3Mg2 square pyramids, and edges with three equivalent S(1)Pm2Mg3 square pyramids. is represented by the CIF file [CIF]
data_Pm2MgS4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.945
_cell_length_b   12.892
_cell_length_c   13.928
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   708.346
_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
  Pm  Pm0  1  0.250  0.121  0.074  1.0
  Pm  Pm1  1  0.750  0.879  0.926  1.0
  Pm  Pm2  1  0.750  0.379  0.574  1.0
  Pm  Pm3  1  0.250  0.621  0.426  1.0
  Pm  Pm4  1  0.250  0.133  0.707  1.0
  Pm  Pm5  1  0.750  0.867  0.293  1.0
  Pm  Pm6  1  0.750  0.367  0.207  1.0
  Pm  Pm7  1  0.250  0.633  0.793  1.0
  Mg  Mg8  1  0.750  0.107  0.462  1.0
  Mg  Mg9  1  0.250  0.893  0.538  1.0
  Mg  Mg10  1  0.250  0.393  0.962  1.0
  Mg  Mg11  1  0.750  0.607  0.038  1.0
  S  S12  1  0.750  0.002  0.614  1.0
  S  S13  1  0.250  0.998  0.386  1.0
  S  S14  1  0.250  0.498  0.114  1.0
  S  S15  1  0.750  0.502  0.886  1.0
  S  S16  1  0.250  0.025  0.885  1.0
  S  S17  1  0.750  0.975  0.115  1.0
  S  S18  1  0.750  0.475  0.385  1.0
  S  S19  1  0.250  0.525  0.615  1.0
  S  S20  1  0.250  0.229  0.245  1.0
  S  S21  1  0.750  0.771  0.755  1.0
  S  S22  1  0.750  0.271  0.745  1.0
  S  S23  1  0.250  0.729  0.255  1.0
  S  S24  1  0.750  0.269  0.016  1.0
  S  S25  1  0.250  0.731  0.984  1.0
  S  S26  1  0.250  0.231  0.516  1.0
  S  S27  1  0.750  0.769  0.484  1.0
[/CIF]
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The crystal structure described by MgPm2S4 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 Pm(1)S6 octahedra, corners with two equivalent Pm(2)S6 octahedra,  an edgeedge with one Pm(1)S6 octahedra, edges with three equivalent Pm(2)S6 octahedra, and edges with four equivalent Mg(1)S5 square pyramids. The corner-sharing octahedral tilt angles are 5°. There are two inequivalent Pm sites. In the first Pm site, Pm(1) is bonded to one S(3), two equivalent S(4), and three equivalent S(2) atoms to form PmS6 octahedra that share corners with three equivalent Pm(2)S6 octahedra, corners with two equivalent Mg(1)S5 square pyramids, edges with two equivalent Pm(2)S6 octahedra, edges with four equivalent Pm(1)S6 octahedra, and  an edgeedge with one Mg(1)S5 square pyramid. The corner-sharing octahedral tilt angles range from 55-59°. In the second Pm site, Pm(2) is bonded to one S(2), one S(4), two equivalent S(1), and two equivalent S(3) atoms to form PmS6 octahedra that share corners with three equivalent Pm(1)S6 octahedra, corners with two equivalent Mg(1)S5 square pyramids, edges with two equivalent Pm(1)S6 octahedra, edges with two equivalent Pm(2)S6 octahedra, and edges with three equivalent Mg(1)S5 square pyramids. The corner-sharing octahedral tilt angles range from 55-59°. There are four inequivalent S sites. In the first S site, S(1) is bonded to three equivalent Mg(1) and two equivalent Pm(2) atoms to form SPm2Mg3 square pyramids that share corners with two equivalent S(4)Pm3Mg2 square pyramids, edges with three equivalent S(4)Pm3Mg2 square pyramids, and edges with four equivalent S(1)Pm2Mg3 square pyramids. In the second S site, S(2) is bonded in a rectangular see-saw-like geometry to one Pm(2) and three equivalent Pm(1) atoms. In the third S site, S(3) is bonded in a distorted trigonal non-coplanar geometry to one Pm(1) and two equivalent Pm(2) atoms. In the fourth S site, S(4) is bonded to two equivalent Mg(1), one Pm(2), and two equivalent Pm(1) atoms to form SPm3Mg2 square pyramids that share corners with two equivalent S(1)Pm2Mg3 square pyramids, edges with two equivalent S(4)Pm3Mg2 square pyramids, and edges with three equivalent S(1)Pm2Mg3 square pyramids. is represented by the CIF file [CIF]
data_Pm2MgS4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.945
_cell_length_b   12.892
_cell_length_c   13.928
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   708.346
_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
  Pm  Pm0  1  0.250  0.121  0.074  1.0
  Pm  Pm1  1  0.750  0.879  0.926  1.0
  Pm  Pm2  1  0.750  0.379  0.574  1.0
  Pm  Pm3  1  0.250  0.621  0.426  1.0
  Pm  Pm4  1  0.250  0.133  0.707  1.0
  Pm  Pm5  1  0.750  0.867  0.293  1.0
  Pm  Pm6  1  0.750  0.367  0.207  1.0
  Pm  Pm7  1  0.250  0.633  0.793  1.0
  Mg  Mg8  1  0.750  0.107  0.462  1.0
  Mg  Mg9  1  0.250  0.893  0.538  1.0
  Mg  Mg10  1  0.250  0.393  0.962  1.0
  Mg  Mg11  1  0.750  0.607  0.038  1.0
  S  S12  1  0.750  0.002  0.614  1.0
  S  S13  1  0.250  0.998  0.386  1.0
  S  S14  1  0.250  0.498  0.114  1.0
  S  S15  1  0.750  0.502  0.886  1.0
  S  S16  1  0.250  0.025  0.885  1.0
  S  S17  1  0.750  0.975  0.115  1.0
  S  S18  1  0.750  0.475  0.385  1.0
  S  S19  1  0.250  0.525  0.615  1.0
  S  S20  1  0.250  0.229  0.245  1.0
  S  S21  1  0.750  0.771  0.755  1.0
  S  S22  1  0.750  0.271  0.745  1.0
  S  S23  1  0.250  0.729  0.255  1.0
  S  S24  1  0.750  0.269  0.016  1.0
  S  S25  1  0.250  0.731  0.984  1.0
  S  S26  1  0.250  0.231  0.516  1.0
  S  S27  1  0.750  0.769  0.484  1.0
[/CIF]
.