The structure described by MgCd2 crystallizes in the orthorhombic Amm2 space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Cd(1), two equivalent Cd(4), and four equivalent Cd(3) atoms to form distorted MgMg4Cd8 cuboctahedra that share corners with six equivalent Mg(1)Mg4Cd8 cuboctahedra, corners with six equivalent Mg(2)Mg4Cd8 cuboctahedra, corners with six equivalent Cd(4)Mg4Cd8 cuboctahedra, edges with three equivalent Mg(2)Mg4Cd8 cuboctahedra, edges with three equivalent Cd(4)Mg4Cd8 cuboctahedra, edges with four equivalent Cd(3)Mg6Cd6 cuboctahedra, edges with eight equivalent Cd(2)Mg4Cd8 cuboctahedra, faces with two equivalent Mg(2)Mg4Cd8 cuboctahedra, faces with two equivalent Cd(2)Mg4Cd8 cuboctahedra, faces with two equivalent Cd(4)Mg4Cd8 cuboctahedra, faces with four equivalent Mg(1)Mg4Cd8 cuboctahedra, faces with four equivalent Cd(3)Mg6Cd6 cuboctahedra, and faces with six equivalent Cd(1)Mg2Cd10 cuboctahedra. In the second Mg site, Mg(2) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Cd(3), two equivalent Cd(4), and four equivalent Cd(2) atoms to form distorted MgMg4Cd8 cuboctahedra that share corners with six equivalent Mg(1)Mg4Cd8 cuboctahedra, corners with six equivalent Mg(2)Mg4Cd8 cuboctahedra, corners with six equivalent Cd(4)Mg4Cd8 cuboctahedra, edges with three equivalent Mg(1)Mg4Cd8 cuboctahedra, edges with three equivalent Cd(4)Mg4Cd8 cuboctahedra, edges with four equivalent Cd(2)Mg4Cd8 cuboctahedra, edges with eight equivalent Cd(1)Mg2Cd10 cuboctahedra, faces with two equivalent Mg(1)Mg4Cd8 cuboctahedra, faces with two equivalent Cd(1)Mg2Cd10 cuboctahedra, faces with two equivalent Cd(4)Mg4Cd8 cuboctahedra, faces with four equivalent Mg(2)Mg4Cd8 cuboctahedra, faces with four equivalent Cd(2)Mg4Cd8 cuboctahedra, and faces with six equivalent Cd(3)Mg6Cd6 cuboctahedra. There are four inequivalent Cd sites. In the first Cd site, Cd(1) is bonded to two equivalent Mg(1), two equivalent Cd(1), two equivalent Cd(2), two equivalent Cd(3), and four equivalent Cd(4) atoms to form distorted CdMg2Cd10 cuboctahedra that share corners with six equivalent Cd(1)Mg2Cd10 cuboctahedra, corners with six equivalent Cd(2)Mg4Cd8 cuboctahedra, corners with six equivalent Cd(3)Mg6Cd6 cuboctahedra, edges with three equivalent Cd(2)Mg4Cd8 cuboctahedra, edges with three equivalent Cd(3)Mg6Cd6 cuboctahedra, edges with four equivalent Cd(4)Mg4Cd8 cuboctahedra, edges with eight equivalent Mg(2)Mg4Cd8 cuboctahedra, faces with two equivalent Mg(2)Mg4Cd8 cuboctahedra, faces with two equivalent Cd(2)Mg4Cd8 cuboctahedra, faces with two equivalent Cd(3)Mg6Cd6 cuboctahedra, faces with four equivalent Cd(1)Mg2Cd10 cuboctahedra, faces with four equivalent Cd(4)Mg4Cd8 cuboctahedra, and faces with six equivalent Mg(1)Mg4Cd8 cuboctahedra. In the second Cd site, Cd(2) is bonded to four equivalent Mg(2), two equivalent Cd(1), two equivalent Cd(2), two equivalent Cd(3), and two equivalent Cd(4) atoms to form distorted CdMg4Cd8 cuboctahedra that share corners with six equivalent Cd(1)Mg2Cd10 cuboctahedra, corners with six equivalent Cd(2)Mg4Cd8 cuboctahedra, corners with six equivalent Cd(3)Mg6Cd6 cuboctahedra, edges with three equivalent Cd(1)Mg2Cd10 cuboctahedra, edges with three equivalent Cd(3)Mg6Cd6 cuboctahedra, edges with four equivalent Mg(2)Mg4Cd8 cuboctahedra, edges with eight equivalent Mg(1)Mg4Cd8 cuboctahedra, faces with two equivalent Mg(1)Mg4Cd8 cuboctahedra, faces with two equivalent Cd(1)Mg2Cd10 cuboctahedra, faces with two equivalent Cd(3)Mg6Cd6 cuboctahedra, faces with four equivalent Mg(2)Mg4Cd8 cuboctahedra, faces with four equivalent Cd(2)Mg4Cd8 cuboctahedra, and faces with six equivalent Cd(4)Mg4Cd8 cuboctahedra. In the third Cd site, Cd(3) is bonded to two equivalent Mg(2), four equivalent Mg(1), two equivalent Cd(1), two equivalent Cd(2), and two equivalent Cd(3) atoms to form distorted CdMg6Cd6 cuboctahedra that share corners with six equivalent Cd(1)Mg2Cd10 cuboctahedra, corners with six equivalent Cd(2)Mg4Cd8 cuboctahedra, corners with six equivalent Cd(3)Mg6Cd6 cuboctahedra, edges with three equivalent Cd(1)Mg2Cd10 cuboctahedra, edges with three equivalent Cd(2)Mg4Cd8 cuboctahedra, edges with four equivalent Mg(1)Mg4Cd8 cuboctahedra, edges with eight equivalent Cd(4)Mg4Cd8 cuboctahedra, faces with two equivalent Cd(1)Mg2Cd10 cuboctahedra, faces with two equivalent Cd(2)Mg4Cd8 cuboctahedra, faces with two equivalent Cd(4)Mg4Cd8 cuboctahedra, faces with four equivalent Mg(1)Mg4Cd8 cuboctahedra, faces with four equivalent Cd(3)Mg6Cd6 cuboctahedra, and faces with six equivalent Mg(2)Mg4Cd8 cuboctahedra. In the fourth Cd site, Cd(4) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Cd(2), two equivalent Cd(4), and four equivalent Cd(1) atoms to form distorted CdMg4Cd8 cuboctahedra that share corners with six equivalent Mg(1)Mg4Cd8 cuboctahedra, corners with six equivalent Mg(2)Mg4Cd8 cuboctahedra, corners with six equivalent Cd(4)Mg4Cd8 cuboctahedra, edges with three equivalent Mg(1)Mg4Cd8 cuboctahedra, edges with three equivalent Mg(2)Mg4Cd8 cuboctahedra, edges with four equivalent Cd(1)Mg2Cd10 cuboctahedra, edges with eight equivalent Cd(3)Mg6Cd6 cuboctahedra, faces with two equivalent Mg(1)Mg4Cd8 cuboctahedra, faces with two equivalent Mg(2)Mg4Cd8 cuboctahedra, faces with two equivalent Cd(3)Mg6Cd6 cuboctahedra, faces with four equivalent Cd(1)Mg2Cd10 cuboctahedra, faces with four equivalent Cd(4)Mg4Cd8 cuboctahedra, and faces with six equivalent Cd(2)Mg4Cd8 cuboctahedra. is represented by the CIF file [CIF]
data_MgCd2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.205
_cell_length_b   4.977
_cell_length_c   8.171
_cell_angle_alpha   90.000
_cell_angle_beta   101.310
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   127.811
_cell_formula_units_Z   2
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
  Cd  Cd0  1  0.000  0.000  0.000  1.0
  Cd  Cd1  1  0.332  0.000  0.663  1.0
  Cd  Cd2  1  0.667  0.000  0.334  1.0
  Cd  Cd3  1  0.443  0.500  0.887  1.0
  Mg  Mg4  1  0.110  0.500  0.220  1.0
  Mg  Mg5  1  0.781  0.500  0.563  1.0
[/CIF]
.
The structure described by MgCd2 crystallizes in the orthorhombic Amm2 space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Cd(1), two equivalent Cd(4), and four equivalent Cd(3) atoms to form distorted MgMg4Cd8 cuboctahedra that share corners with six equivalent Mg(1)Mg4Cd8 cuboctahedra, corners with six equivalent Mg(2)Mg4Cd8 cuboctahedra, corners with six equivalent Cd(4)Mg4Cd8 cuboctahedra, edges with three equivalent Mg(2)Mg4Cd8 cuboctahedra, edges with three equivalent Cd(4)Mg4Cd8 cuboctahedra, edges with four equivalent Cd(3)Mg6Cd6 cuboctahedra, edges with eight equivalent Cd(2)Mg4Cd8 cuboctahedra, faces with two equivalent Mg(2)Mg4Cd8 cuboctahedra, faces with two equivalent Cd(2)Mg4Cd8 cuboctahedra, faces with two equivalent Cd(4)Mg4Cd8 cuboctahedra, faces with four equivalent Mg(1)Mg4Cd8 cuboctahedra, faces with four equivalent Cd(3)Mg6Cd6 cuboctahedra, and faces with six equivalent Cd(1)Mg2Cd10 cuboctahedra. In the second Mg site, Mg(2) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Cd(3), two equivalent Cd(4), and four equivalent Cd(2) atoms to form distorted MgMg4Cd8 cuboctahedra that share corners with six equivalent Mg(1)Mg4Cd8 cuboctahedra, corners with six equivalent Mg(2)Mg4Cd8 cuboctahedra, corners with six equivalent Cd(4)Mg4Cd8 cuboctahedra, edges with three equivalent Mg(1)Mg4Cd8 cuboctahedra, edges with three equivalent Cd(4)Mg4Cd8 cuboctahedra, edges with four equivalent Cd(2)Mg4Cd8 cuboctahedra, edges with eight equivalent Cd(1)Mg2Cd10 cuboctahedra, faces with two equivalent Mg(1)Mg4Cd8 cuboctahedra, faces with two equivalent Cd(1)Mg2Cd10 cuboctahedra, faces with two equivalent Cd(4)Mg4Cd8 cuboctahedra, faces with four equivalent Mg(2)Mg4Cd8 cuboctahedra, faces with four equivalent Cd(2)Mg4Cd8 cuboctahedra, and faces with six equivalent Cd(3)Mg6Cd6 cuboctahedra. There are four inequivalent Cd sites. In the first Cd site, Cd(1) is bonded to two equivalent Mg(1), two equivalent Cd(1), two equivalent Cd(2), two equivalent Cd(3), and four equivalent Cd(4) atoms to form distorted CdMg2Cd10 cuboctahedra that share corners with six equivalent Cd(1)Mg2Cd10 cuboctahedra, corners with six equivalent Cd(2)Mg4Cd8 cuboctahedra, corners with six equivalent Cd(3)Mg6Cd6 cuboctahedra, edges with three equivalent Cd(2)Mg4Cd8 cuboctahedra, edges with three equivalent Cd(3)Mg6Cd6 cuboctahedra, edges with four equivalent Cd(4)Mg4Cd8 cuboctahedra, edges with eight equivalent Mg(2)Mg4Cd8 cuboctahedra, faces with two equivalent Mg(2)Mg4Cd8 cuboctahedra, faces with two equivalent Cd(2)Mg4Cd8 cuboctahedra, faces with two equivalent Cd(3)Mg6Cd6 cuboctahedra, faces with four equivalent Cd(1)Mg2Cd10 cuboctahedra, faces with four equivalent Cd(4)Mg4Cd8 cuboctahedra, and faces with six equivalent Mg(1)Mg4Cd8 cuboctahedra. In the second Cd site, Cd(2) is bonded to four equivalent Mg(2), two equivalent Cd(1), two equivalent Cd(2), two equivalent Cd(3), and two equivalent Cd(4) atoms to form distorted CdMg4Cd8 cuboctahedra that share corners with six equivalent Cd(1)Mg2Cd10 cuboctahedra, corners with six equivalent Cd(2)Mg4Cd8 cuboctahedra, corners with six equivalent Cd(3)Mg6Cd6 cuboctahedra, edges with three equivalent Cd(1)Mg2Cd10 cuboctahedra, edges with three equivalent Cd(3)Mg6Cd6 cuboctahedra, edges with four equivalent Mg(2)Mg4Cd8 cuboctahedra, edges with eight equivalent Mg(1)Mg4Cd8 cuboctahedra, faces with two equivalent Mg(1)Mg4Cd8 cuboctahedra, faces with two equivalent Cd(1)Mg2Cd10 cuboctahedra, faces with two equivalent Cd(3)Mg6Cd6 cuboctahedra, faces with four equivalent Mg(2)Mg4Cd8 cuboctahedra, faces with four equivalent Cd(2)Mg4Cd8 cuboctahedra, and faces with six equivalent Cd(4)Mg4Cd8 cuboctahedra. In the third Cd site, Cd(3) is bonded to two equivalent Mg(2), four equivalent Mg(1), two equivalent Cd(1), two equivalent Cd(2), and two equivalent Cd(3) atoms to form distorted CdMg6Cd6 cuboctahedra that share corners with six equivalent Cd(1)Mg2Cd10 cuboctahedra, corners with six equivalent Cd(2)Mg4Cd8 cuboctahedra, corners with six equivalent Cd(3)Mg6Cd6 cuboctahedra, edges with three equivalent Cd(1)Mg2Cd10 cuboctahedra, edges with three equivalent Cd(2)Mg4Cd8 cuboctahedra, edges with four equivalent Mg(1)Mg4Cd8 cuboctahedra, edges with eight equivalent Cd(4)Mg4Cd8 cuboctahedra, faces with two equivalent Cd(1)Mg2Cd10 cuboctahedra, faces with two equivalent Cd(2)Mg4Cd8 cuboctahedra, faces with two equivalent Cd(4)Mg4Cd8 cuboctahedra, faces with four equivalent Mg(1)Mg4Cd8 cuboctahedra, faces with four equivalent Cd(3)Mg6Cd6 cuboctahedra, and faces with six equivalent Mg(2)Mg4Cd8 cuboctahedra. In the fourth Cd site, Cd(4) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Cd(2), two equivalent Cd(4), and four equivalent Cd(1) atoms to form distorted CdMg4Cd8 cuboctahedra that share corners with six equivalent Mg(1)Mg4Cd8 cuboctahedra, corners with six equivalent Mg(2)Mg4Cd8 cuboctahedra, corners with six equivalent Cd(4)Mg4Cd8 cuboctahedra, edges with three equivalent Mg(1)Mg4Cd8 cuboctahedra, edges with three equivalent Mg(2)Mg4Cd8 cuboctahedra, edges with four equivalent Cd(1)Mg2Cd10 cuboctahedra, edges with eight equivalent Cd(3)Mg6Cd6 cuboctahedra, faces with two equivalent Mg(1)Mg4Cd8 cuboctahedra, faces with two equivalent Mg(2)Mg4Cd8 cuboctahedra, faces with two equivalent Cd(3)Mg6Cd6 cuboctahedra, faces with four equivalent Cd(1)Mg2Cd10 cuboctahedra, faces with four equivalent Cd(4)Mg4Cd8 cuboctahedra, and faces with six equivalent Cd(2)Mg4Cd8 cuboctahedra. is represented by the CIF file [CIF]
data_MgCd2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.205
_cell_length_b   4.977
_cell_length_c   8.171
_cell_angle_alpha   90.000
_cell_angle_beta   101.310
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   127.811
_cell_formula_units_Z   2
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
  Cd  Cd0  1  0.000  0.000  0.000  1.0
  Cd  Cd1  1  0.332  0.000  0.663  1.0
  Cd  Cd2  1  0.667  0.000  0.334  1.0
  Cd  Cd3  1  0.443  0.500  0.887  1.0
  Mg  Mg4  1  0.110  0.500  0.220  1.0
  Mg  Mg5  1  0.781  0.500  0.563  1.0
[/CIF]
.