The material described by Mg6SnSi crystallizes in the orthorhombic Amm2 space group. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Mg(2), two equivalent Mg(4), two equivalent Sn(1), and two equivalent Si(1) atoms to form distorted MgMg4Si2Sn2 cuboctahedra that share corners with two equivalent Mg(3)Mg6Sn2 cuboctahedra, corners with six equivalent Mg(1)Mg4Si2Sn2 cuboctahedra, edges with two equivalent Mg(3)Mg6Sn2 cuboctahedra, edges with four equivalent Mg(4)Mg10Si2 cuboctahedra, edges with five equivalent Mg(1)Mg4Si2Sn2 cuboctahedra,  a faceface with one Mg(1)Mg4Si2Sn2 cuboctahedra, and faces with two equivalent Mg(3)Mg6Sn2 cuboctahedra. In the second Mg site, Mg(2) is bonded in a 12-coordinate geometry to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent Sn(1), and two equivalent Si(1) atoms. In the third Mg site, Mg(3) is bonded to two equivalent Mg(4), four equivalent Mg(2), and two equivalent Sn(1) atoms to form distorted MgMg6Sn2 cuboctahedra that share corners with four equivalent Mg(1)Mg4Si2Sn2 cuboctahedra, corners with eight equivalent Mg(3)Mg6Sn2 cuboctahedra, edges with four equivalent Mg(4)Mg10Si2 cuboctahedra, edges with four equivalent Mg(1)Mg4Si2Sn2 cuboctahedra, and faces with four equivalent Mg(1)Mg4Si2Sn2 cuboctahedra. In the fourth Mg site, Mg(4) is bonded to two equivalent Mg(3), four equivalent Mg(1), four equivalent Mg(2), and two equivalent Si(1) atoms to form distorted MgMg10Si2 cuboctahedra that share corners with six equivalent Mg(4)Mg10Si2 cuboctahedra, edges with four equivalent Mg(3)Mg6Sn2 cuboctahedra, edges with eight equivalent Mg(1)Mg4Si2Sn2 cuboctahedra, and faces with two equivalent Mg(4)Mg10Si2 cuboctahedra. Sn(1) is bonded in a 10-coordinate geometry to two equivalent Mg(3), four equivalent Mg(1), and four equivalent Mg(2) atoms. Si(1) is bonded in a 10-coordinate geometry to two equivalent Mg(4), four equivalent Mg(1), and four equivalent Mg(2) atoms. is represented by the CIF card [CIF]
data_Mg6SiSn
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.098
_cell_length_b   6.184
_cell_length_c   6.184
_cell_angle_alpha   116.981
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   173.719
_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  0.500  0.666  0.835  1.0
  Mg  Mg1  1  0.500  0.165  0.334  1.0
  Mg  Mg2  1  0.000  0.827  0.656  1.0
  Mg  Mg3  1  0.000  0.344  0.173  1.0
  Mg  Mg4  1  0.000  0.334  0.666  1.0
  Mg  Mg5  1  0.000  0.829  0.171  1.0
  Si  Si6  1  0.500  0.668  0.332  1.0
  Sn  Sn7  1  0.500  0.166  0.834  1.0
[/CIF]
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The material described by Mg6SnSi crystallizes in the orthorhombic Amm2 space group. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Mg(2), two equivalent Mg(4), two equivalent Sn(1), and two equivalent Si(1) atoms to form distorted MgMg4Si2Sn2 cuboctahedra that share corners with two equivalent Mg(3)Mg6Sn2 cuboctahedra, corners with six equivalent Mg(1)Mg4Si2Sn2 cuboctahedra, edges with two equivalent Mg(3)Mg6Sn2 cuboctahedra, edges with four equivalent Mg(4)Mg10Si2 cuboctahedra, edges with five equivalent Mg(1)Mg4Si2Sn2 cuboctahedra,  a faceface with one Mg(1)Mg4Si2Sn2 cuboctahedra, and faces with two equivalent Mg(3)Mg6Sn2 cuboctahedra. In the second Mg site, Mg(2) is bonded in a 12-coordinate geometry to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent Sn(1), and two equivalent Si(1) atoms. In the third Mg site, Mg(3) is bonded to two equivalent Mg(4), four equivalent Mg(2), and two equivalent Sn(1) atoms to form distorted MgMg6Sn2 cuboctahedra that share corners with four equivalent Mg(1)Mg4Si2Sn2 cuboctahedra, corners with eight equivalent Mg(3)Mg6Sn2 cuboctahedra, edges with four equivalent Mg(4)Mg10Si2 cuboctahedra, edges with four equivalent Mg(1)Mg4Si2Sn2 cuboctahedra, and faces with four equivalent Mg(1)Mg4Si2Sn2 cuboctahedra. In the fourth Mg site, Mg(4) is bonded to two equivalent Mg(3), four equivalent Mg(1), four equivalent Mg(2), and two equivalent Si(1) atoms to form distorted MgMg10Si2 cuboctahedra that share corners with six equivalent Mg(4)Mg10Si2 cuboctahedra, edges with four equivalent Mg(3)Mg6Sn2 cuboctahedra, edges with eight equivalent Mg(1)Mg4Si2Sn2 cuboctahedra, and faces with two equivalent Mg(4)Mg10Si2 cuboctahedra. Sn(1) is bonded in a 10-coordinate geometry to two equivalent Mg(3), four equivalent Mg(1), and four equivalent Mg(2) atoms. Si(1) is bonded in a 10-coordinate geometry to two equivalent Mg(4), four equivalent Mg(1), and four equivalent Mg(2) atoms. is represented by the CIF card [CIF]
data_Mg6SiSn
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.098
_cell_length_b   6.184
_cell_length_c   6.184
_cell_angle_alpha   116.981
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   173.719
_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  0.500  0.666  0.835  1.0
  Mg  Mg1  1  0.500  0.165  0.334  1.0
  Mg  Mg2  1  0.000  0.827  0.656  1.0
  Mg  Mg3  1  0.000  0.344  0.173  1.0
  Mg  Mg4  1  0.000  0.334  0.666  1.0
  Mg  Mg5  1  0.000  0.829  0.171  1.0
  Si  Si6  1  0.500  0.668  0.332  1.0
  Sn  Sn7  1  0.500  0.166  0.834  1.0
[/CIF]
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