The structure described by Mg6SnSb 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(3), two equivalent Sn(1), and two equivalent Sb(1) atoms to form distorted MgMg4Sn2Sb2 cuboctahedra that share corners with two equivalent Mg(4)Mg6Sb2 cuboctahedra, corners with two equivalent Mg(2)Mg8Sn2Sb2 cuboctahedra, corners with five equivalent Sb(1)Mg10Sn2 cuboctahedra, corners with six equivalent Mg(1)Mg4Sn2Sb2 cuboctahedra, corners with six equivalent Sn(1)Mg10Sb2 cuboctahedra, edges with two equivalent Mg(4)Mg6Sb2 cuboctahedra, edges with four equivalent Mg(3)Mg10Sn2 cuboctahedra, edges with four equivalent Mg(2)Mg8Sn2Sb2 cuboctahedra, edges with five equivalent Mg(1)Mg4Sn2Sb2 cuboctahedra,  a faceface with one Mg(1)Mg4Sn2Sb2 cuboctahedra,  a faceface with one Sb(1)Mg10Sn2 cuboctahedra, faces with two equivalent Mg(4)Mg6Sb2 cuboctahedra, faces with two equivalent Sn(1)Mg10Sb2 cuboctahedra, and faces with six equivalent Mg(2)Mg8Sn2Sb2 cuboctahedra. In the second Mg site, Mg(2) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent Sn(1), and two equivalent Sb(1) atoms to form distorted MgMg8Sn2Sb2 cuboctahedra that share corners with two equivalent Mg(1)Mg4Sn2Sb2 cuboctahedra, corners with two equivalent Mg(4)Mg6Sb2 cuboctahedra, corners with four equivalent Mg(3)Mg10Sn2 cuboctahedra, corners with ten equivalent Mg(2)Mg8Sn2Sb2 cuboctahedra, edges with two equivalent Mg(3)Mg10Sn2 cuboctahedra, edges with two equivalent Mg(2)Mg8Sn2Sb2 cuboctahedra, edges with three equivalent Mg(4)Mg6Sb2 cuboctahedra, edges with four equivalent Mg(1)Mg4Sn2Sb2 cuboctahedra, edges with four equivalent Sn(1)Mg10Sb2 cuboctahedra, edges with four equivalent Sb(1)Mg10Sn2 cuboctahedra,  a faceface with one Mg(4)Mg6Sb2 cuboctahedra, faces with two equivalent Mg(3)Mg10Sn2 cuboctahedra, faces with two equivalent Sn(1)Mg10Sb2 cuboctahedra, faces with two equivalent Sb(1)Mg10Sn2 cuboctahedra, faces with four equivalent Mg(2)Mg8Sn2Sb2 cuboctahedra, and faces with six equivalent Mg(1)Mg4Sn2Sb2 cuboctahedra. In the third Mg site, Mg(3) is bonded to two equivalent Mg(4), four equivalent Mg(1), four equivalent Mg(2), and two equivalent Sn(1) atoms to form distorted MgMg10Sn2 cuboctahedra that share corners with six equivalent Mg(3)Mg10Sn2 cuboctahedra, corners with eight equivalent Mg(2)Mg8Sn2Sb2 cuboctahedra, edges with four equivalent Mg(4)Mg6Sb2 cuboctahedra, edges with four equivalent Mg(2)Mg8Sn2Sb2 cuboctahedra, edges with four equivalent Sn(1)Mg10Sb2 cuboctahedra, edges with eight equivalent Mg(1)Mg4Sn2Sb2 cuboctahedra, faces with two equivalent Mg(3)Mg10Sn2 cuboctahedra, faces with two equivalent Sn(1)Mg10Sb2 cuboctahedra, faces with four equivalent Mg(2)Mg8Sn2Sb2 cuboctahedra, and faces with six equivalent Sb(1)Mg10Sn2 cuboctahedra. In the fourth Mg site, Mg(4) is bonded to two equivalent Mg(3), four equivalent Mg(2), and two equivalent Sb(1) atoms to form distorted MgMg6Sb2 cuboctahedra that share corners with four equivalent Mg(1)Mg4Sn2Sb2 cuboctahedra, corners with four equivalent Mg(2)Mg8Sn2Sb2 cuboctahedra, corners with four equivalent Sb(1)Mg10Sn2 cuboctahedra, corners with eight equivalent Mg(4)Mg6Sb2 cuboctahedra, edges with two equivalent Sn(1)Mg10Sb2 cuboctahedra, edges with two equivalent Sb(1)Mg10Sn2 cuboctahedra, edges with four equivalent Mg(3)Mg10Sn2 cuboctahedra, edges with four equivalent Mg(1)Mg4Sn2Sb2 cuboctahedra, edges with six equivalent Mg(2)Mg8Sn2Sb2 cuboctahedra, faces with two equivalent Mg(2)Mg8Sn2Sb2 cuboctahedra, faces with four equivalent Mg(1)Mg4Sn2Sb2 cuboctahedra, and faces with four equivalent Sn(1)Mg10Sb2 cuboctahedra. Sn(1) is bonded to two equivalent Mg(3), four equivalent Mg(1), four equivalent Mg(2), and two equivalent Sb(1) atoms to form SnMg10Sb2 cuboctahedra that share corners with four equivalent Sb(1)Mg10Sn2 cuboctahedra, corners with six equivalent Sn(1)Mg10Sb2 cuboctahedra, corners with twelve equivalent Mg(1)Mg4Sn2Sb2 cuboctahedra, edges with two equivalent Mg(4)Mg6Sb2 cuboctahedra, edges with two equivalent Sb(1)Mg10Sn2 cuboctahedra, edges with four equivalent Mg(3)Mg10Sn2 cuboctahedra, edges with eight equivalent Mg(2)Mg8Sn2Sb2 cuboctahedra, faces with two equivalent Mg(3)Mg10Sn2 cuboctahedra, faces with two equivalent Sn(1)Mg10Sb2 cuboctahedra, faces with two equivalent Sb(1)Mg10Sn2 cuboctahedra, faces with four equivalent Mg(1)Mg4Sn2Sb2 cuboctahedra, faces with four equivalent Mg(4)Mg6Sb2 cuboctahedra, and faces with four equivalent Mg(2)Mg8Sn2Sb2 cuboctahedra. Sb(1) is bonded to two equivalent Mg(4), four equivalent Mg(1), four equivalent Mg(2), and two equivalent Sn(1) atoms to form SbMg10Sn2 cuboctahedra that share corners with four equivalent Mg(4)Mg6Sb2 cuboctahedra, corners with four equivalent Sn(1)Mg10Sb2 cuboctahedra, corners with six equivalent Sb(1)Mg10Sn2 cuboctahedra, corners with ten equivalent Mg(1)Mg4Sn2Sb2 cuboctahedra, edges with two equivalent Mg(4)Mg6Sb2 cuboctahedra, edges with two equivalent Sn(1)Mg10Sb2 cuboctahedra, edges with eight equivalent Mg(2)Mg8Sn2Sb2 cuboctahedra, faces with two equivalent Mg(1)Mg4Sn2Sb2 cuboctahedra, faces with two equivalent Sn(1)Mg10Sb2 cuboctahedra, faces with two equivalent Sb(1)Mg10Sn2 cuboctahedra, faces with four equivalent Mg(2)Mg8Sn2Sb2 cuboctahedra, and faces with six equivalent Mg(3)Mg10Sn2 cuboctahedra. is represented by the CIF file [CIF]
data_Mg6SnSb
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.262
_cell_length_b   6.394
_cell_length_c   6.394
_cell_angle_alpha   118.669
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   188.763
_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  1.000  0.167  0.334  1.0
  Mg  Mg1  1  1.000  0.666  0.833  1.0
  Mg  Mg2  1  0.500  0.333  0.168  1.0
  Mg  Mg3  1  0.500  0.832  0.667  1.0
  Mg  Mg4  1  0.500  0.334  0.666  1.0
  Mg  Mg5  1  0.500  0.834  0.166  1.0
  Sb  Sb6  1  0.000  0.667  0.333  1.0
  Sn  Sn7  1  0.000  0.167  0.833  1.0
[/CIF]
.
The structure described by Mg6SnSb 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(3), two equivalent Sn(1), and two equivalent Sb(1) atoms to form distorted MgMg4Sn2Sb2 cuboctahedra that share corners with two equivalent Mg(4)Mg6Sb2 cuboctahedra, corners with two equivalent Mg(2)Mg8Sn2Sb2 cuboctahedra, corners with five equivalent Sb(1)Mg10Sn2 cuboctahedra, corners with six equivalent Mg(1)Mg4Sn2Sb2 cuboctahedra, corners with six equivalent Sn(1)Mg10Sb2 cuboctahedra, edges with two equivalent Mg(4)Mg6Sb2 cuboctahedra, edges with four equivalent Mg(3)Mg10Sn2 cuboctahedra, edges with four equivalent Mg(2)Mg8Sn2Sb2 cuboctahedra, edges with five equivalent Mg(1)Mg4Sn2Sb2 cuboctahedra,  a faceface with one Mg(1)Mg4Sn2Sb2 cuboctahedra,  a faceface with one Sb(1)Mg10Sn2 cuboctahedra, faces with two equivalent Mg(4)Mg6Sb2 cuboctahedra, faces with two equivalent Sn(1)Mg10Sb2 cuboctahedra, and faces with six equivalent Mg(2)Mg8Sn2Sb2 cuboctahedra. In the second Mg site, Mg(2) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent Sn(1), and two equivalent Sb(1) atoms to form distorted MgMg8Sn2Sb2 cuboctahedra that share corners with two equivalent Mg(1)Mg4Sn2Sb2 cuboctahedra, corners with two equivalent Mg(4)Mg6Sb2 cuboctahedra, corners with four equivalent Mg(3)Mg10Sn2 cuboctahedra, corners with ten equivalent Mg(2)Mg8Sn2Sb2 cuboctahedra, edges with two equivalent Mg(3)Mg10Sn2 cuboctahedra, edges with two equivalent Mg(2)Mg8Sn2Sb2 cuboctahedra, edges with three equivalent Mg(4)Mg6Sb2 cuboctahedra, edges with four equivalent Mg(1)Mg4Sn2Sb2 cuboctahedra, edges with four equivalent Sn(1)Mg10Sb2 cuboctahedra, edges with four equivalent Sb(1)Mg10Sn2 cuboctahedra,  a faceface with one Mg(4)Mg6Sb2 cuboctahedra, faces with two equivalent Mg(3)Mg10Sn2 cuboctahedra, faces with two equivalent Sn(1)Mg10Sb2 cuboctahedra, faces with two equivalent Sb(1)Mg10Sn2 cuboctahedra, faces with four equivalent Mg(2)Mg8Sn2Sb2 cuboctahedra, and faces with six equivalent Mg(1)Mg4Sn2Sb2 cuboctahedra. In the third Mg site, Mg(3) is bonded to two equivalent Mg(4), four equivalent Mg(1), four equivalent Mg(2), and two equivalent Sn(1) atoms to form distorted MgMg10Sn2 cuboctahedra that share corners with six equivalent Mg(3)Mg10Sn2 cuboctahedra, corners with eight equivalent Mg(2)Mg8Sn2Sb2 cuboctahedra, edges with four equivalent Mg(4)Mg6Sb2 cuboctahedra, edges with four equivalent Mg(2)Mg8Sn2Sb2 cuboctahedra, edges with four equivalent Sn(1)Mg10Sb2 cuboctahedra, edges with eight equivalent Mg(1)Mg4Sn2Sb2 cuboctahedra, faces with two equivalent Mg(3)Mg10Sn2 cuboctahedra, faces with two equivalent Sn(1)Mg10Sb2 cuboctahedra, faces with four equivalent Mg(2)Mg8Sn2Sb2 cuboctahedra, and faces with six equivalent Sb(1)Mg10Sn2 cuboctahedra. In the fourth Mg site, Mg(4) is bonded to two equivalent Mg(3), four equivalent Mg(2), and two equivalent Sb(1) atoms to form distorted MgMg6Sb2 cuboctahedra that share corners with four equivalent Mg(1)Mg4Sn2Sb2 cuboctahedra, corners with four equivalent Mg(2)Mg8Sn2Sb2 cuboctahedra, corners with four equivalent Sb(1)Mg10Sn2 cuboctahedra, corners with eight equivalent Mg(4)Mg6Sb2 cuboctahedra, edges with two equivalent Sn(1)Mg10Sb2 cuboctahedra, edges with two equivalent Sb(1)Mg10Sn2 cuboctahedra, edges with four equivalent Mg(3)Mg10Sn2 cuboctahedra, edges with four equivalent Mg(1)Mg4Sn2Sb2 cuboctahedra, edges with six equivalent Mg(2)Mg8Sn2Sb2 cuboctahedra, faces with two equivalent Mg(2)Mg8Sn2Sb2 cuboctahedra, faces with four equivalent Mg(1)Mg4Sn2Sb2 cuboctahedra, and faces with four equivalent Sn(1)Mg10Sb2 cuboctahedra. Sn(1) is bonded to two equivalent Mg(3), four equivalent Mg(1), four equivalent Mg(2), and two equivalent Sb(1) atoms to form SnMg10Sb2 cuboctahedra that share corners with four equivalent Sb(1)Mg10Sn2 cuboctahedra, corners with six equivalent Sn(1)Mg10Sb2 cuboctahedra, corners with twelve equivalent Mg(1)Mg4Sn2Sb2 cuboctahedra, edges with two equivalent Mg(4)Mg6Sb2 cuboctahedra, edges with two equivalent Sb(1)Mg10Sn2 cuboctahedra, edges with four equivalent Mg(3)Mg10Sn2 cuboctahedra, edges with eight equivalent Mg(2)Mg8Sn2Sb2 cuboctahedra, faces with two equivalent Mg(3)Mg10Sn2 cuboctahedra, faces with two equivalent Sn(1)Mg10Sb2 cuboctahedra, faces with two equivalent Sb(1)Mg10Sn2 cuboctahedra, faces with four equivalent Mg(1)Mg4Sn2Sb2 cuboctahedra, faces with four equivalent Mg(4)Mg6Sb2 cuboctahedra, and faces with four equivalent Mg(2)Mg8Sn2Sb2 cuboctahedra. Sb(1) is bonded to two equivalent Mg(4), four equivalent Mg(1), four equivalent Mg(2), and two equivalent Sn(1) atoms to form SbMg10Sn2 cuboctahedra that share corners with four equivalent Mg(4)Mg6Sb2 cuboctahedra, corners with four equivalent Sn(1)Mg10Sb2 cuboctahedra, corners with six equivalent Sb(1)Mg10Sn2 cuboctahedra, corners with ten equivalent Mg(1)Mg4Sn2Sb2 cuboctahedra, edges with two equivalent Mg(4)Mg6Sb2 cuboctahedra, edges with two equivalent Sn(1)Mg10Sb2 cuboctahedra, edges with eight equivalent Mg(2)Mg8Sn2Sb2 cuboctahedra, faces with two equivalent Mg(1)Mg4Sn2Sb2 cuboctahedra, faces with two equivalent Sn(1)Mg10Sb2 cuboctahedra, faces with two equivalent Sb(1)Mg10Sn2 cuboctahedra, faces with four equivalent Mg(2)Mg8Sn2Sb2 cuboctahedra, and faces with six equivalent Mg(3)Mg10Sn2 cuboctahedra. is represented by the CIF file [CIF]
data_Mg6SnSb
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.262
_cell_length_b   6.394
_cell_length_c   6.394
_cell_angle_alpha   118.669
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   188.763
_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  1.000  0.167  0.334  1.0
  Mg  Mg1  1  1.000  0.666  0.833  1.0
  Mg  Mg2  1  0.500  0.333  0.168  1.0
  Mg  Mg3  1  0.500  0.832  0.667  1.0
  Mg  Mg4  1  0.500  0.334  0.666  1.0
  Mg  Mg5  1  0.500  0.834  0.166  1.0
  Sb  Sb6  1  0.000  0.667  0.333  1.0
  Sn  Sn7  1  0.000  0.167  0.833  1.0
[/CIF]
.