The structure described by Mg3Ce crystallizes in the orthorhombic Pmm2 space group. There are three inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Mg(1), two equivalent Mg(2), four equivalent Mg(3), and four equivalent Ce(1) atoms to form MgCe4Mg8 cuboctahedra that share corners with eight equivalent Ce(1)Ce2Mg10 cuboctahedra, corners with ten equivalent Mg(1)Ce4Mg8 cuboctahedra, edges with two equivalent Mg(1)Ce4Mg8 cuboctahedra, edges with four equivalent Ce(1)Ce2Mg10 cuboctahedra, faces with four equivalent Mg(1)Ce4Mg8 cuboctahedra, and faces with four equivalent Ce(1)Ce2Mg10 cuboctahedra. In the second Mg site, Mg(2) is bonded in a 10-coordinate geometry to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), and four equivalent Ce(1) atoms. In the third Mg site, Mg(3) is bonded in a 10-coordinate geometry to two equivalent Mg(2), two equivalent Mg(3), four equivalent Mg(1), and two equivalent Ce(1) atoms. Ce(1) is bonded to two equivalent Mg(3), four equivalent Mg(1), four equivalent Mg(2), and two equivalent Ce(1) atoms to form CeCe2Mg10 cuboctahedra that share corners with eight equivalent Mg(1)Ce4Mg8 cuboctahedra, corners with ten equivalent Ce(1)Ce2Mg10 cuboctahedra, edges with two equivalent Ce(1)Ce2Mg10 cuboctahedra, edges with four equivalent Mg(1)Ce4Mg8 cuboctahedra, faces with four equivalent Mg(1)Ce4Mg8 cuboctahedra, and faces with four equivalent Ce(1)Ce2Mg10 cuboctahedra. is represented by the CIF file [CIF]
data_CeMg3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.133
_cell_length_b   5.313
_cell_length_c   6.225
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   103.623
_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
  Ce  Ce0  1  0.500  0.000  0.155  1.0
  Mg  Mg1  1  0.000  0.000  0.653  1.0
  Mg  Mg2  1  0.000  0.500  0.361  1.0
  Mg  Mg3  1  0.500  0.500  0.831  1.0
[/CIF]
.
The structure described by Mg3Ce crystallizes in the orthorhombic Pmm2 space group. There are three inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Mg(1), two equivalent Mg(2), four equivalent Mg(3), and four equivalent Ce(1) atoms to form MgCe4Mg8 cuboctahedra that share corners with eight equivalent Ce(1)Ce2Mg10 cuboctahedra, corners with ten equivalent Mg(1)Ce4Mg8 cuboctahedra, edges with two equivalent Mg(1)Ce4Mg8 cuboctahedra, edges with four equivalent Ce(1)Ce2Mg10 cuboctahedra, faces with four equivalent Mg(1)Ce4Mg8 cuboctahedra, and faces with four equivalent Ce(1)Ce2Mg10 cuboctahedra. In the second Mg site, Mg(2) is bonded in a 10-coordinate geometry to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), and four equivalent Ce(1) atoms. In the third Mg site, Mg(3) is bonded in a 10-coordinate geometry to two equivalent Mg(2), two equivalent Mg(3), four equivalent Mg(1), and two equivalent Ce(1) atoms. Ce(1) is bonded to two equivalent Mg(3), four equivalent Mg(1), four equivalent Mg(2), and two equivalent Ce(1) atoms to form CeCe2Mg10 cuboctahedra that share corners with eight equivalent Mg(1)Ce4Mg8 cuboctahedra, corners with ten equivalent Ce(1)Ce2Mg10 cuboctahedra, edges with two equivalent Ce(1)Ce2Mg10 cuboctahedra, edges with four equivalent Mg(1)Ce4Mg8 cuboctahedra, faces with four equivalent Mg(1)Ce4Mg8 cuboctahedra, and faces with four equivalent Ce(1)Ce2Mg10 cuboctahedra. is represented by the CIF file [CIF]
data_CeMg3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.133
_cell_length_b   5.313
_cell_length_c   6.225
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   103.623
_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
  Ce  Ce0  1  0.500  0.000  0.155  1.0
  Mg  Mg1  1  0.000  0.000  0.653  1.0
  Mg  Mg2  1  0.000  0.500  0.361  1.0
  Mg  Mg3  1  0.500  0.500  0.831  1.0
[/CIF]
.