The material described by BaMg2Sn2 crystallizes in the tetragonal P4/nmm space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 16-coordinate geometry to four equivalent Mg(1), four equivalent Mg(3), four equivalent Sn(1), and four equivalent Sn(2) atoms. In the second Ba site, Ba(2) is bonded in a 16-coordinate geometry to four equivalent Mg(1), four equivalent Mg(2), four equivalent Sn(3), and four equivalent Sn(4) atoms. There are three inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Ba(1), two equivalent Ba(2), two equivalent Sn(1), and two equivalent Sn(3) atoms to form MgBa4Sn4 tetrahedra that share corners with six equivalent Mg(2)Ba4Sn4 tetrahedra, corners with six equivalent Sn(2)Ba4Mg4 tetrahedra,  an edgeedge with one Mg(2)Ba4Sn4 tetrahedra,  an edgeedge with one Sn(2)Ba4Mg4 tetrahedra, edges with four equivalent Mg(1)Ba4Sn4 tetrahedra, and faces with four equivalent Mg(1)Ba4Sn4 tetrahedra. In the second Mg site, Mg(2) is bonded to four equivalent Ba(2) and four equivalent Sn(4) atoms to form a mixture of corner, face, and edge-sharing MgBa4Sn4 tetrahedra. In the third Mg site, Mg(3) is bonded in a 5-coordinate geometry to four equivalent Ba(1), one Sn(1), and four equivalent Sn(2) atoms. There are four inequivalent Sn sites. In the first Sn site, Sn(1) is bonded in a 9-coordinate geometry to four equivalent Ba(1), one Mg(3), and four equivalent Mg(1) atoms. In the second Sn site, Sn(2) is bonded to four equivalent Ba(1) and four equivalent Mg(3) atoms to form distorted SnBa4Mg4 tetrahedra that share corners with twelve equivalent Mg(1)Ba4Sn4 tetrahedra, edges with two equivalent Mg(1)Ba4Sn4 tetrahedra, edges with four equivalent Sn(2)Ba4Mg4 tetrahedra, and faces with four equivalent Sn(2)Ba4Mg4 tetrahedra. In the third Sn site, Sn(3) is bonded in a 9-coordinate geometry to four equivalent Ba(2), four equivalent Mg(1), and one Sn(4) atom. In the fourth Sn site, Sn(4) is bonded in a 9-coordinate geometry to four equivalent Ba(2), four equivalent Mg(2), and one Sn(3) atom. is represented by the CIF file [CIF]
data_Ba(MgSn)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.922
_cell_length_b   4.922
_cell_length_c   24.332
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   589.470
_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
  Ba  Ba0  1  0.000  0.500  0.379  1.0
  Ba  Ba1  1  0.500  0.000  0.621  1.0
  Ba  Ba2  1  0.000  0.500  0.871  1.0
  Ba  Ba3  1  0.500  0.000  0.129  1.0
  Mg  Mg4  1  0.000  0.000  0.748  1.0
  Mg  Mg5  1  0.500  0.500  0.748  1.0
  Mg  Mg6  1  0.000  0.000  0.252  1.0
  Mg  Mg7  1  0.500  0.500  0.252  1.0
  Mg  Mg8  1  0.500  0.500  0.000  1.0
  Mg  Mg9  1  0.000  0.000  0.000  1.0
  Mg  Mg10  1  0.500  0.000  0.434  1.0
  Mg  Mg11  1  0.000  0.500  0.566  1.0
  Sn  Sn12  1  0.500  0.000  0.318  1.0
  Sn  Sn13  1  0.000  0.500  0.682  1.0
  Sn  Sn14  1  0.000  0.000  0.500  1.0
  Sn  Sn15  1  0.500  0.500  0.500  1.0
  Sn  Sn16  1  0.500  0.000  0.815  1.0
  Sn  Sn17  1  0.000  0.500  0.185  1.0
  Sn  Sn18  1  0.500  0.000  0.934  1.0
  Sn  Sn19  1  0.000  0.500  0.066  1.0
[/CIF]
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The material described by BaMg2Sn2 crystallizes in the tetragonal P4/nmm space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 16-coordinate geometry to four equivalent Mg(1), four equivalent Mg(3), four equivalent Sn(1), and four equivalent Sn(2) atoms. In the second Ba site, Ba(2) is bonded in a 16-coordinate geometry to four equivalent Mg(1), four equivalent Mg(2), four equivalent Sn(3), and four equivalent Sn(4) atoms. There are three inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Ba(1), two equivalent Ba(2), two equivalent Sn(1), and two equivalent Sn(3) atoms to form MgBa4Sn4 tetrahedra that share corners with six equivalent Mg(2)Ba4Sn4 tetrahedra, corners with six equivalent Sn(2)Ba4Mg4 tetrahedra,  an edgeedge with one Mg(2)Ba4Sn4 tetrahedra,  an edgeedge with one Sn(2)Ba4Mg4 tetrahedra, edges with four equivalent Mg(1)Ba4Sn4 tetrahedra, and faces with four equivalent Mg(1)Ba4Sn4 tetrahedra. In the second Mg site, Mg(2) is bonded to four equivalent Ba(2) and four equivalent Sn(4) atoms to form a mixture of corner, face, and edge-sharing MgBa4Sn4 tetrahedra. In the third Mg site, Mg(3) is bonded in a 5-coordinate geometry to four equivalent Ba(1), one Sn(1), and four equivalent Sn(2) atoms. There are four inequivalent Sn sites. In the first Sn site, Sn(1) is bonded in a 9-coordinate geometry to four equivalent Ba(1), one Mg(3), and four equivalent Mg(1) atoms. In the second Sn site, Sn(2) is bonded to four equivalent Ba(1) and four equivalent Mg(3) atoms to form distorted SnBa4Mg4 tetrahedra that share corners with twelve equivalent Mg(1)Ba4Sn4 tetrahedra, edges with two equivalent Mg(1)Ba4Sn4 tetrahedra, edges with four equivalent Sn(2)Ba4Mg4 tetrahedra, and faces with four equivalent Sn(2)Ba4Mg4 tetrahedra. In the third Sn site, Sn(3) is bonded in a 9-coordinate geometry to four equivalent Ba(2), four equivalent Mg(1), and one Sn(4) atom. In the fourth Sn site, Sn(4) is bonded in a 9-coordinate geometry to four equivalent Ba(2), four equivalent Mg(2), and one Sn(3) atom. is represented by the CIF file [CIF]
data_Ba(MgSn)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.922
_cell_length_b   4.922
_cell_length_c   24.332
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   589.470
_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
  Ba  Ba0  1  0.000  0.500  0.379  1.0
  Ba  Ba1  1  0.500  0.000  0.621  1.0
  Ba  Ba2  1  0.000  0.500  0.871  1.0
  Ba  Ba3  1  0.500  0.000  0.129  1.0
  Mg  Mg4  1  0.000  0.000  0.748  1.0
  Mg  Mg5  1  0.500  0.500  0.748  1.0
  Mg  Mg6  1  0.000  0.000  0.252  1.0
  Mg  Mg7  1  0.500  0.500  0.252  1.0
  Mg  Mg8  1  0.500  0.500  0.000  1.0
  Mg  Mg9  1  0.000  0.000  0.000  1.0
  Mg  Mg10  1  0.500  0.000  0.434  1.0
  Mg  Mg11  1  0.000  0.500  0.566  1.0
  Sn  Sn12  1  0.500  0.000  0.318  1.0
  Sn  Sn13  1  0.000  0.500  0.682  1.0
  Sn  Sn14  1  0.000  0.000  0.500  1.0
  Sn  Sn15  1  0.500  0.500  0.500  1.0
  Sn  Sn16  1  0.500  0.000  0.815  1.0
  Sn  Sn17  1  0.000  0.500  0.185  1.0
  Sn  Sn18  1  0.500  0.000  0.934  1.0
  Sn  Sn19  1  0.000  0.500  0.066  1.0
[/CIF]
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