The structure described by MgCe2 is beta-derived structured and crystallizes in the trigonal R32 space group. There are three inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to three equivalent Mg(1); three equivalent Ce(2); and six Ce(1,1) atoms to form distorted MgCe9Mg3 cuboctahedra that share corners with six equivalent Ce(2)Ce6Mg6 cuboctahedra; corners with twelve Mg(1,1,1)Ce9Mg3 cuboctahedra; edges with six equivalent Mg(1)Ce9Mg3 cuboctahedra; edges with twelve Ce(1,1)Ce8Mg4 cuboctahedra; faces with four Mg(1,1)Ce9Mg3 cuboctahedra; faces with four equivalent Ce(2)Ce6Mg6 cuboctahedra; and faces with twelve Ce(1,1)Ce8Mg4 cuboctahedra. In the second Mg site, Mg(1) is bonded to three equivalent Mg(1); three equivalent Ce(2); and six Ce(1,1) atoms to form distorted MgCe9Mg3 cuboctahedra that share corners with six equivalent Ce(2)Ce6Mg6 cuboctahedra; corners with twelve Mg(1,1)Ce9Mg3 cuboctahedra; edges with six equivalent Mg(1)Ce9Mg3 cuboctahedra; edges with twelve Ce(1,1)Ce8Mg4 cuboctahedra; faces with four equivalent Mg(1)Ce9Mg3 cuboctahedra; faces with four equivalent Ce(2)Ce6Mg6 cuboctahedra; and faces with twelve Ce(1,1)Ce8Mg4 cuboctahedra. In the third Mg site, Mg(1) is bonded to three equivalent Mg(1); three equivalent Ce(2); and six Ce(1,1,1) atoms to form distorted MgCe9Mg3 cuboctahedra that share corners with six equivalent Ce(2)Ce6Mg6 cuboctahedra; corners with twelve Mg(1,1)Ce9Mg3 cuboctahedra; edges with six equivalent Mg(1)Ce9Mg3 cuboctahedra; edges with twelve Ce(1,1,1)Ce8Mg4 cuboctahedra; faces with four equivalent Mg(1)Ce9Mg3 cuboctahedra; faces with four equivalent Ce(2)Ce6Mg6 cuboctahedra; and faces with twelve Ce(1,1,1)Ce8Mg4 cuboctahedra. There are four inequivalent Ce sites. In the first Ce site, Ce(1) is bonded to four Mg(1,1); two equivalent Ce(2); and six equivalent Ce(1) atoms to form distorted CeCe8Mg4 cuboctahedra that share corners with eighteen Ce(1,1,1)Ce8Mg4 cuboctahedra; edges with four equivalent Ce(2)Ce6Mg6 cuboctahedra; edges with six equivalent Ce(1)Ce8Mg4 cuboctahedra; edges with eight Mg(1,1)Ce9Mg3 cuboctahedra; faces with four equivalent Ce(2)Ce6Mg6 cuboctahedra; faces with eight Mg(1,1)Ce9Mg3 cuboctahedra; and faces with eight Ce(1,1)Ce8Mg4 cuboctahedra. In the second Ce site, Ce(2) is bonded to six Mg(1,1) and six Ce(1,1) atoms to form CeCe6Mg6 cuboctahedra that share corners with six equivalent Ce(2)Ce6Mg6 cuboctahedra; corners with twelve Mg(1,1)Ce9Mg3 cuboctahedra; edges with six equivalent Ce(2)Ce6Mg6 cuboctahedra; edges with twelve Ce(1,1)Ce8Mg4 cuboctahedra; faces with eight Mg(1,1,1)Ce9Mg3 cuboctahedra; and faces with twelve Ce(1,1)Ce8Mg4 cuboctahedra. In the third Ce site, Ce(1) is bonded to four Mg(1,1); two equivalent Ce(2); and six Ce(1,1) atoms to form distorted CeCe8Mg4 cuboctahedra that share corners with eighteen Ce(1,1)Ce8Mg4 cuboctahedra; edges with four equivalent Ce(2)Ce6Mg6 cuboctahedra; edges with six equivalent Ce(1)Ce8Mg4 cuboctahedra; edges with eight Mg(1,1)Ce9Mg3 cuboctahedra; faces with four equivalent Ce(2)Ce6Mg6 cuboctahedra; faces with eight Mg(1,1)Ce9Mg3 cuboctahedra; and faces with eight Ce(1,1)Ce8Mg4 cuboctahedra. In the fourth Ce site, Ce(1) is bonded to four Mg(1,1); two equivalent Ce(2); and six Ce(1,1) atoms to form distorted CeCe8Mg4 cuboctahedra that share corners with eighteen Ce(1,1,1)Ce8Mg4 cuboctahedra; edges with four equivalent Ce(2)Ce6Mg6 cuboctahedra; edges with six equivalent Ce(1)Ce8Mg4 cuboctahedra; edges with eight Mg(1,1)Ce9Mg3 cuboctahedra; faces with four equivalent Ce(2)Ce6Mg6 cuboctahedra; faces with eight Mg(1,1)Ce9Mg3 cuboctahedra; and faces with eight Ce(1,1,1)Ce8Mg4 cuboctahedra. is represented by the CIF card [CIF]
data_Ce2Mg
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.543
_cell_length_b   6.543
_cell_length_c   6.543
_cell_angle_alpha   52.447
_cell_angle_beta   52.447
_cell_angle_gamma   52.447
_symmetry_Int_Tables_number   1
_cell_volume   162.976
_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
  Ce  Ce0  1  0.000  0.697  0.303  1.0
  Ce  Ce1  1  0.697  0.303  0.000  1.0
  Ce  Ce2  1  0.500  0.500  0.500  1.0
  Ce  Ce3  1  0.303  0.000  0.697  1.0
  Mg  Mg4  1  0.829  0.829  0.829  1.0
  Mg  Mg5  1  0.171  0.171  0.171  1.0
[/CIF]
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The structure described by MgCe2 is beta-derived structured and crystallizes in the trigonal R32 space group. There are three inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to three equivalent Mg(1); three equivalent Ce(2); and six Ce(1,1) atoms to form distorted MgCe9Mg3 cuboctahedra that share corners with six equivalent Ce(2)Ce6Mg6 cuboctahedra; corners with twelve Mg(1,1,1)Ce9Mg3 cuboctahedra; edges with six equivalent Mg(1)Ce9Mg3 cuboctahedra; edges with twelve Ce(1,1)Ce8Mg4 cuboctahedra; faces with four Mg(1,1)Ce9Mg3 cuboctahedra; faces with four equivalent Ce(2)Ce6Mg6 cuboctahedra; and faces with twelve Ce(1,1)Ce8Mg4 cuboctahedra. In the second Mg site, Mg(1) is bonded to three equivalent Mg(1); three equivalent Ce(2); and six Ce(1,1) atoms to form distorted MgCe9Mg3 cuboctahedra that share corners with six equivalent Ce(2)Ce6Mg6 cuboctahedra; corners with twelve Mg(1,1)Ce9Mg3 cuboctahedra; edges with six equivalent Mg(1)Ce9Mg3 cuboctahedra; edges with twelve Ce(1,1)Ce8Mg4 cuboctahedra; faces with four equivalent Mg(1)Ce9Mg3 cuboctahedra; faces with four equivalent Ce(2)Ce6Mg6 cuboctahedra; and faces with twelve Ce(1,1)Ce8Mg4 cuboctahedra. In the third Mg site, Mg(1) is bonded to three equivalent Mg(1); three equivalent Ce(2); and six Ce(1,1,1) atoms to form distorted MgCe9Mg3 cuboctahedra that share corners with six equivalent Ce(2)Ce6Mg6 cuboctahedra; corners with twelve Mg(1,1)Ce9Mg3 cuboctahedra; edges with six equivalent Mg(1)Ce9Mg3 cuboctahedra; edges with twelve Ce(1,1,1)Ce8Mg4 cuboctahedra; faces with four equivalent Mg(1)Ce9Mg3 cuboctahedra; faces with four equivalent Ce(2)Ce6Mg6 cuboctahedra; and faces with twelve Ce(1,1,1)Ce8Mg4 cuboctahedra. There are four inequivalent Ce sites. In the first Ce site, Ce(1) is bonded to four Mg(1,1); two equivalent Ce(2); and six equivalent Ce(1) atoms to form distorted CeCe8Mg4 cuboctahedra that share corners with eighteen Ce(1,1,1)Ce8Mg4 cuboctahedra; edges with four equivalent Ce(2)Ce6Mg6 cuboctahedra; edges with six equivalent Ce(1)Ce8Mg4 cuboctahedra; edges with eight Mg(1,1)Ce9Mg3 cuboctahedra; faces with four equivalent Ce(2)Ce6Mg6 cuboctahedra; faces with eight Mg(1,1)Ce9Mg3 cuboctahedra; and faces with eight Ce(1,1)Ce8Mg4 cuboctahedra. In the second Ce site, Ce(2) is bonded to six Mg(1,1) and six Ce(1,1) atoms to form CeCe6Mg6 cuboctahedra that share corners with six equivalent Ce(2)Ce6Mg6 cuboctahedra; corners with twelve Mg(1,1)Ce9Mg3 cuboctahedra; edges with six equivalent Ce(2)Ce6Mg6 cuboctahedra; edges with twelve Ce(1,1)Ce8Mg4 cuboctahedra; faces with eight Mg(1,1,1)Ce9Mg3 cuboctahedra; and faces with twelve Ce(1,1)Ce8Mg4 cuboctahedra. In the third Ce site, Ce(1) is bonded to four Mg(1,1); two equivalent Ce(2); and six Ce(1,1) atoms to form distorted CeCe8Mg4 cuboctahedra that share corners with eighteen Ce(1,1)Ce8Mg4 cuboctahedra; edges with four equivalent Ce(2)Ce6Mg6 cuboctahedra; edges with six equivalent Ce(1)Ce8Mg4 cuboctahedra; edges with eight Mg(1,1)Ce9Mg3 cuboctahedra; faces with four equivalent Ce(2)Ce6Mg6 cuboctahedra; faces with eight Mg(1,1)Ce9Mg3 cuboctahedra; and faces with eight Ce(1,1)Ce8Mg4 cuboctahedra. In the fourth Ce site, Ce(1) is bonded to four Mg(1,1); two equivalent Ce(2); and six Ce(1,1) atoms to form distorted CeCe8Mg4 cuboctahedra that share corners with eighteen Ce(1,1,1)Ce8Mg4 cuboctahedra; edges with four equivalent Ce(2)Ce6Mg6 cuboctahedra; edges with six equivalent Ce(1)Ce8Mg4 cuboctahedra; edges with eight Mg(1,1)Ce9Mg3 cuboctahedra; faces with four equivalent Ce(2)Ce6Mg6 cuboctahedra; faces with eight Mg(1,1)Ce9Mg3 cuboctahedra; and faces with eight Ce(1,1,1)Ce8Mg4 cuboctahedra. is represented by the CIF card [CIF]
data_Ce2Mg
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.543
_cell_length_b   6.543
_cell_length_c   6.543
_cell_angle_alpha   52.447
_cell_angle_beta   52.447
_cell_angle_gamma   52.447
_symmetry_Int_Tables_number   1
_cell_volume   162.976
_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
  Ce  Ce0  1  0.000  0.697  0.303  1.0
  Ce  Ce1  1  0.697  0.303  0.000  1.0
  Ce  Ce2  1  0.500  0.500  0.500  1.0
  Ce  Ce3  1  0.303  0.000  0.697  1.0
  Mg  Mg4  1  0.829  0.829  0.829  1.0
  Mg  Mg5  1  0.171  0.171  0.171  1.0
[/CIF]
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