The material structure described by Mg3Sb crystallizes in the orthorhombic Imm2 space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to four equivalent Sb(1) atoms to form distorted MgSb4 cuboctahedra that share corners with four equivalent Mg(1)Sb4 cuboctahedra, corners with sixteen equivalent Mg(2)Sb3 cuboctahedra, edges with four equivalent Mg(2)Sb3 cuboctahedra, and edges with four equivalent Mg(1)Sb4 cuboctahedra. In the second Mg site, Mg(2) is bonded to three equivalent Sb(1) atoms to form distorted MgSb3 cuboctahedra that share corners with eight equivalent Mg(1)Sb4 cuboctahedra, corners with thirteen equivalent Mg(2)Sb3 cuboctahedra,  an edgeedge with one Mg(2)Sb3 cuboctahedra, and edges with two equivalent Mg(1)Sb4 cuboctahedra. Sb(1) is bonded to four equivalent Mg(1) and six equivalent Mg(2) atoms to form a mixture of distorted edge, face, and corner-sharing SbMg10 cuboctahedra. is represented by the CIF file [CIF]
data_Mg3Sb
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.104
_cell_length_b   6.104
_cell_length_c   6.104
_cell_angle_alpha   148.795
_cell_angle_beta   126.453
_cell_angle_gamma   63.290
_symmetry_Int_Tables_number   1
_cell_volume   93.838
_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  0.166  0.500  0.666  1.0
  Mg  Mg1  1  0.248  0.250  0.999  1.0
  Mg  Mg2  1  0.749  0.750  0.999  1.0
  Sb  Sb3  1  0.671  0.000  0.671  1.0
[/CIF]
.
The material structure described by Mg3Sb crystallizes in the orthorhombic Imm2 space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to four equivalent Sb(1) atoms to form distorted MgSb4 cuboctahedra that share corners with four equivalent Mg(1)Sb4 cuboctahedra, corners with sixteen equivalent Mg(2)Sb3 cuboctahedra, edges with four equivalent Mg(2)Sb3 cuboctahedra, and edges with four equivalent Mg(1)Sb4 cuboctahedra. In the second Mg site, Mg(2) is bonded to three equivalent Sb(1) atoms to form distorted MgSb3 cuboctahedra that share corners with eight equivalent Mg(1)Sb4 cuboctahedra, corners with thirteen equivalent Mg(2)Sb3 cuboctahedra,  an edgeedge with one Mg(2)Sb3 cuboctahedra, and edges with two equivalent Mg(1)Sb4 cuboctahedra. Sb(1) is bonded to four equivalent Mg(1) and six equivalent Mg(2) atoms to form a mixture of distorted edge, face, and corner-sharing SbMg10 cuboctahedra. is represented by the CIF file [CIF]
data_Mg3Sb
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.104
_cell_length_b   6.104
_cell_length_c   6.104
_cell_angle_alpha   148.795
_cell_angle_beta   126.453
_cell_angle_gamma   63.290
_symmetry_Int_Tables_number   1
_cell_volume   93.838
_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  0.166  0.500  0.666  1.0
  Mg  Mg1  1  0.248  0.250  0.999  1.0
  Mg  Mg2  1  0.749  0.750  0.999  1.0
  Sb  Sb3  1  0.671  0.000  0.671  1.0
[/CIF]
.