The structure described by Mg12Ce crystallizes in the tetragonal I4/mmm space group. There are three inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a distorted q6 geometry to two equivalent Mg(1), four equivalent Mg(2), four equivalent Mg(3), and two equivalent Ce(1) atoms. In the second Mg site, Mg(3) is bonded to two equivalent Mg(3), four equivalent Mg(1), four equivalent Mg(2), and two equivalent Ce(1) atoms to form a mixture of distorted corner, edge, and face-sharing MgCe2Mg10 cuboctahedra. In the third Mg site, Mg(2) is bonded in a 10-coordinate geometry to one Mg(2), four equivalent Mg(1), four equivalent Mg(3), and one Ce(1) atom. Ce(1) is bonded in a 20-coordinate geometry to four equivalent Mg(2), eight equivalent Mg(1), and eight equivalent Mg(3) atoms. is represented by the CIF file [CIF]
data_CeMg12
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.830
_cell_length_b   7.830
_cell_length_c   7.823
_cell_angle_alpha   98.126
_cell_angle_beta   98.126
_cell_angle_gamma   135.778
_symmetry_Int_Tables_number   1
_cell_volume   310.046
_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  0.000  0.000  0.000  1.0
  Mg  Mg1  1  0.500  0.287  0.788  1.0
  Mg  Mg2  1  0.500  0.713  0.212  1.0
  Mg  Mg3  1  0.713  0.500  0.212  1.0
  Mg  Mg4  1  0.287  0.500  0.788  1.0
  Mg  Mg5  1  1.000  0.352  0.352  1.0
  Mg  Mg6  1  0.000  0.648  0.648  1.0
  Mg  Mg7  1  0.648  0.000  0.648  1.0
  Mg  Mg8  1  0.352  1.000  0.352  1.0
  Mg  Mg9  1  0.000  0.000  0.500  1.0
  Mg  Mg10  1  0.500  0.500  0.500  1.0
  Mg  Mg11  1  0.500  0.000  0.000  1.0
  Mg  Mg12  1  0.000  0.500  0.000  1.0
[/CIF]
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The structure described by Mg12Ce crystallizes in the tetragonal I4/mmm space group. There are three inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a distorted q6 geometry to two equivalent Mg(1), four equivalent Mg(2), four equivalent Mg(3), and two equivalent Ce(1) atoms. In the second Mg site, Mg(3) is bonded to two equivalent Mg(3), four equivalent Mg(1), four equivalent Mg(2), and two equivalent Ce(1) atoms to form a mixture of distorted corner, edge, and face-sharing MgCe2Mg10 cuboctahedra. In the third Mg site, Mg(2) is bonded in a 10-coordinate geometry to one Mg(2), four equivalent Mg(1), four equivalent Mg(3), and one Ce(1) atom. Ce(1) is bonded in a 20-coordinate geometry to four equivalent Mg(2), eight equivalent Mg(1), and eight equivalent Mg(3) atoms. is represented by the CIF file [CIF]
data_CeMg12
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.830
_cell_length_b   7.830
_cell_length_c   7.823
_cell_angle_alpha   98.126
_cell_angle_beta   98.126
_cell_angle_gamma   135.778
_symmetry_Int_Tables_number   1
_cell_volume   310.046
_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  0.000  0.000  0.000  1.0
  Mg  Mg1  1  0.500  0.287  0.788  1.0
  Mg  Mg2  1  0.500  0.713  0.212  1.0
  Mg  Mg3  1  0.713  0.500  0.212  1.0
  Mg  Mg4  1  0.287  0.500  0.788  1.0
  Mg  Mg5  1  1.000  0.352  0.352  1.0
  Mg  Mg6  1  0.000  0.648  0.648  1.0
  Mg  Mg7  1  0.648  0.000  0.648  1.0
  Mg  Mg8  1  0.352  1.000  0.352  1.0
  Mg  Mg9  1  0.000  0.000  0.500  1.0
  Mg  Mg10  1  0.500  0.500  0.500  1.0
  Mg  Mg11  1  0.500  0.000  0.000  1.0
  Mg  Mg12  1  0.000  0.500  0.000  1.0
[/CIF]
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