The crystal structure described by Mg4Se3S is Chalcopyrite-like structured and crystallizes in the trigonal R3m space group. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to one Se(1) and three equivalent S(1) atoms to form MgSeS3 tetrahedra that share corners with three equivalent Mg(4)Se3S tetrahedra, corners with three equivalent Mg(2)Se4 tetrahedra, and corners with six equivalent Mg(1)SeS3 tetrahedra. In the second Mg site, Mg(2) is bonded to one Se(2) and three equivalent Se(1) atoms to form MgSe4 tetrahedra that share corners with three equivalent Mg(3)Se4 tetrahedra, corners with three equivalent Mg(1)SeS3 tetrahedra, and corners with six equivalent Mg(2)Se4 tetrahedra. In the third Mg site, Mg(3) is bonded to one Se(3) and three equivalent Se(2) atoms to form MgSe4 tetrahedra that share corners with three equivalent Mg(4)Se3S tetrahedra, corners with three equivalent Mg(2)Se4 tetrahedra, and corners with six equivalent Mg(3)Se4 tetrahedra. In the fourth Mg site, Mg(4) is bonded to three equivalent Se(3) and one S(1) atom to form MgSe3S tetrahedra that share corners with three equivalent Mg(3)Se4 tetrahedra, corners with three equivalent Mg(1)SeS3 tetrahedra, and corners with six equivalent Mg(4)Se3S tetrahedra. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded to one Mg(1) and three equivalent Mg(2) atoms to form SeMg4 tetrahedra that share corners with three equivalent Se(2)Mg4 tetrahedra, corners with three equivalent S(1)Mg4 tetrahedra, and corners with six equivalent Se(1)Mg4 tetrahedra. In the second Se site, Se(2) is bonded to one Mg(2) and three equivalent Mg(3) atoms to form corner-sharing SeMg4 tetrahedra. In the third Se site, Se(3) is bonded to one Mg(3) and three equivalent Mg(4) atoms to form SeMg4 tetrahedra that share corners with three equivalent Se(2)Mg4 tetrahedra, corners with three equivalent S(1)Mg4 tetrahedra, and corners with six equivalent Se(3)Mg4 tetrahedra. S(1) is bonded to one Mg(4) and three equivalent Mg(1) atoms to form SMg4 tetrahedra that share corners with three equivalent Se(1)Mg4 tetrahedra, corners with three equivalent Se(3)Mg4 tetrahedra, and corners with six equivalent S(1)Mg4 tetrahedra. is represented by the Crystallographic Information File (CIF) [CIF]
data_Mg4Se3S
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   13.905
_cell_length_b   13.905
_cell_length_c   13.905
_cell_angle_alpha   17.340
_cell_angle_beta   17.340
_cell_angle_gamma   17.340
_symmetry_Int_Tables_number   1
_cell_volume   208.406
_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  0.002  0.002  0.002  1.0
  Mg  Mg1  1  0.250  0.250  0.250  1.0
  Mg  Mg2  1  0.500  0.500  0.500  1.0
  Mg  Mg3  1  0.748  0.748  0.748  1.0
  Se  Se4  1  0.939  0.939  0.939  1.0
  Se  Se5  1  0.188  0.188  0.188  1.0
  Se  Se6  1  0.437  0.437  0.437  1.0
  S  S7  1  0.687  0.687  0.687  1.0
[/CIF]
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The crystal structure described by Mg4Se3S is Chalcopyrite-like structured and crystallizes in the trigonal R3m space group. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to one Se(1) and three equivalent S(1) atoms to form MgSeS3 tetrahedra that share corners with three equivalent Mg(4)Se3S tetrahedra, corners with three equivalent Mg(2)Se4 tetrahedra, and corners with six equivalent Mg(1)SeS3 tetrahedra. In the second Mg site, Mg(2) is bonded to one Se(2) and three equivalent Se(1) atoms to form MgSe4 tetrahedra that share corners with three equivalent Mg(3)Se4 tetrahedra, corners with three equivalent Mg(1)SeS3 tetrahedra, and corners with six equivalent Mg(2)Se4 tetrahedra. In the third Mg site, Mg(3) is bonded to one Se(3) and three equivalent Se(2) atoms to form MgSe4 tetrahedra that share corners with three equivalent Mg(4)Se3S tetrahedra, corners with three equivalent Mg(2)Se4 tetrahedra, and corners with six equivalent Mg(3)Se4 tetrahedra. In the fourth Mg site, Mg(4) is bonded to three equivalent Se(3) and one S(1) atom to form MgSe3S tetrahedra that share corners with three equivalent Mg(3)Se4 tetrahedra, corners with three equivalent Mg(1)SeS3 tetrahedra, and corners with six equivalent Mg(4)Se3S tetrahedra. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded to one Mg(1) and three equivalent Mg(2) atoms to form SeMg4 tetrahedra that share corners with three equivalent Se(2)Mg4 tetrahedra, corners with three equivalent S(1)Mg4 tetrahedra, and corners with six equivalent Se(1)Mg4 tetrahedra. In the second Se site, Se(2) is bonded to one Mg(2) and three equivalent Mg(3) atoms to form corner-sharing SeMg4 tetrahedra. In the third Se site, Se(3) is bonded to one Mg(3) and three equivalent Mg(4) atoms to form SeMg4 tetrahedra that share corners with three equivalent Se(2)Mg4 tetrahedra, corners with three equivalent S(1)Mg4 tetrahedra, and corners with six equivalent Se(3)Mg4 tetrahedra. S(1) is bonded to one Mg(4) and three equivalent Mg(1) atoms to form SMg4 tetrahedra that share corners with three equivalent Se(1)Mg4 tetrahedra, corners with three equivalent Se(3)Mg4 tetrahedra, and corners with six equivalent S(1)Mg4 tetrahedra. is represented by the Crystallographic Information File (CIF) [CIF]
data_Mg4Se3S
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   13.905
_cell_length_b   13.905
_cell_length_c   13.905
_cell_angle_alpha   17.340
_cell_angle_beta   17.340
_cell_angle_gamma   17.340
_symmetry_Int_Tables_number   1
_cell_volume   208.406
_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  0.002  0.002  0.002  1.0
  Mg  Mg1  1  0.250  0.250  0.250  1.0
  Mg  Mg2  1  0.500  0.500  0.500  1.0
  Mg  Mg3  1  0.748  0.748  0.748  1.0
  Se  Se4  1  0.939  0.939  0.939  1.0
  Se  Se5  1  0.188  0.188  0.188  1.0
  Se  Se6  1  0.437  0.437  0.437  1.0
  S  S7  1  0.687  0.687  0.687  1.0
[/CIF]
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