The structure described by MgSm2Se4 crystallizes in the orthorhombic Pnma space group. Mg(1) is bonded in a trigonal pyramidal geometry to one Se(2), one Se(3), and two equivalent Se(1) atoms. There are two inequivalent Sm sites. In the first Sm site, Sm(1) is bonded in a 7-coordinate geometry to one Se(2), two equivalent Se(3), and four equivalent Se(1) atoms. In the second Sm site, Sm(2) is bonded in a 6-coordinate geometry to one Se(2), one Se(3), and four equivalent Se(1) atoms. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded to one Mg(1), two equivalent Sm(1), and two equivalent Sm(2) atoms to form a mixture of distorted face, corner, and edge-sharing SeSm4Mg square pyramids. In the second Se site, Se(2) is bonded in a T-shaped geometry to one Mg(1), one Sm(1), and one Sm(2) atom. In the third Se site, Se(3) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Sm(2), and two equivalent Sm(1) atoms. is represented by the CIF card [CIF]
data_Sm2MgSe4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.298
_cell_length_b   7.769
_cell_length_c   12.291
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   792.316
_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
  Sm  Sm0  1  0.053  0.750  0.313  1.0
  Sm  Sm1  1  0.947  0.250  0.687  1.0
  Sm  Sm2  1  0.447  0.250  0.813  1.0
  Sm  Sm3  1  0.553  0.750  0.187  1.0
  Sm  Sm4  1  0.061  0.250  0.027  1.0
  Sm  Sm5  1  0.939  0.750  0.973  1.0
  Sm  Sm6  1  0.439  0.750  0.527  1.0
  Sm  Sm7  1  0.561  0.250  0.473  1.0
  Mg  Mg8  1  0.179  0.250  0.409  1.0
  Mg  Mg9  1  0.821  0.750  0.591  1.0
  Mg  Mg10  1  0.321  0.750  0.909  1.0
  Mg  Mg11  1  0.679  0.250  0.091  1.0
  Se  Se12  1  0.136  0.500  0.844  1.0
  Se  Se13  1  0.864  0.500  0.156  1.0
  Se  Se14  1  0.364  0.500  0.344  1.0
  Se  Se15  1  0.636  0.500  0.656  1.0
  Se  Se16  1  0.636  1.000  0.656  1.0
  Se  Se17  1  0.364  0.000  0.344  1.0
  Se  Se18  1  0.864  0.000  0.156  1.0
  Se  Se19  1  0.136  1.000  0.844  1.0
  Se  Se20  1  0.891  0.250  0.454  1.0
  Se  Se21  1  0.109  0.750  0.546  1.0
  Se  Se22  1  0.609  0.750  0.954  1.0
  Se  Se23  1  0.391  0.250  0.046  1.0
  Se  Se24  1  0.224  0.750  0.112  1.0
  Se  Se25  1  0.776  0.250  0.888  1.0
  Se  Se26  1  0.276  0.250  0.612  1.0
  Se  Se27  1  0.724  0.750  0.388  1.0
[/CIF]
.
The structure described by MgSm2Se4 crystallizes in the orthorhombic Pnma space group. Mg(1) is bonded in a trigonal pyramidal geometry to one Se(2), one Se(3), and two equivalent Se(1) atoms. There are two inequivalent Sm sites. In the first Sm site, Sm(1) is bonded in a 7-coordinate geometry to one Se(2), two equivalent Se(3), and four equivalent Se(1) atoms. In the second Sm site, Sm(2) is bonded in a 6-coordinate geometry to one Se(2), one Se(3), and four equivalent Se(1) atoms. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded to one Mg(1), two equivalent Sm(1), and two equivalent Sm(2) atoms to form a mixture of distorted face, corner, and edge-sharing SeSm4Mg square pyramids. In the second Se site, Se(2) is bonded in a T-shaped geometry to one Mg(1), one Sm(1), and one Sm(2) atom. In the third Se site, Se(3) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Sm(2), and two equivalent Sm(1) atoms. is represented by the CIF card [CIF]
data_Sm2MgSe4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.298
_cell_length_b   7.769
_cell_length_c   12.291
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   792.316
_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
  Sm  Sm0  1  0.053  0.750  0.313  1.0
  Sm  Sm1  1  0.947  0.250  0.687  1.0
  Sm  Sm2  1  0.447  0.250  0.813  1.0
  Sm  Sm3  1  0.553  0.750  0.187  1.0
  Sm  Sm4  1  0.061  0.250  0.027  1.0
  Sm  Sm5  1  0.939  0.750  0.973  1.0
  Sm  Sm6  1  0.439  0.750  0.527  1.0
  Sm  Sm7  1  0.561  0.250  0.473  1.0
  Mg  Mg8  1  0.179  0.250  0.409  1.0
  Mg  Mg9  1  0.821  0.750  0.591  1.0
  Mg  Mg10  1  0.321  0.750  0.909  1.0
  Mg  Mg11  1  0.679  0.250  0.091  1.0
  Se  Se12  1  0.136  0.500  0.844  1.0
  Se  Se13  1  0.864  0.500  0.156  1.0
  Se  Se14  1  0.364  0.500  0.344  1.0
  Se  Se15  1  0.636  0.500  0.656  1.0
  Se  Se16  1  0.636  1.000  0.656  1.0
  Se  Se17  1  0.364  0.000  0.344  1.0
  Se  Se18  1  0.864  0.000  0.156  1.0
  Se  Se19  1  0.136  1.000  0.844  1.0
  Se  Se20  1  0.891  0.250  0.454  1.0
  Se  Se21  1  0.109  0.750  0.546  1.0
  Se  Se22  1  0.609  0.750  0.954  1.0
  Se  Se23  1  0.391  0.250  0.046  1.0
  Se  Se24  1  0.224  0.750  0.112  1.0
  Se  Se25  1  0.776  0.250  0.888  1.0
  Se  Se26  1  0.276  0.250  0.612  1.0
  Se  Se27  1  0.724  0.750  0.388  1.0
[/CIF]
.