The material described by MgCa crystallizes in the trigonal P3m1 space group. There are three inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to three equivalent Ca(2), six equivalent Ca(1), and three equivalent Mg(1) atoms to form distorted CaCa9Mg3 cuboctahedra that share corners with six equivalent Ca(3)Ca6Mg6 cuboctahedra, corners with six equivalent Ca(1)Ca9Mg3 cuboctahedra, edges with six equivalent Ca(1)Ca9Mg3 cuboctahedra, edges with six equivalent Ca(2)Ca9Mg3 cuboctahedra,  a faceface with one Ca(3)Ca6Mg6 cuboctahedra, faces with six equivalent Ca(1)Ca9Mg3 cuboctahedra, and faces with six equivalent Ca(2)Ca9Mg3 cuboctahedra. In the second Ca site, Ca(2) is bonded to three equivalent Ca(1), six equivalent Ca(2), and three equivalent Mg(2) atoms to form a mixture of distorted edge, face, and corner-sharing CaCa9Mg3 cuboctahedra. In the third Ca site, Ca(3) is bonded to six equivalent Ca(3), three equivalent Mg(1), and three equivalent Mg(3) atoms to form distorted CaCa6Mg6 cuboctahedra that share corners with six equivalent Ca(3)Ca6Mg6 cuboctahedra, corners with six equivalent Ca(1)Ca9Mg3 cuboctahedra, edges with six equivalent Ca(3)Ca6Mg6 cuboctahedra,  a faceface with one Ca(1)Ca9Mg3 cuboctahedra, and faces with six equivalent Ca(3)Ca6Mg6 cuboctahedra. There are three inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 6-coordinate geometry to three equivalent Ca(1) and three equivalent Ca(3) atoms. In the second Mg site, Mg(2) is bonded in a 6-coordinate geometry to three equivalent Ca(2) and three equivalent Mg(3) atoms. In the third Mg site, Mg(3) is bonded in a 6-coordinate geometry to three equivalent Ca(3) and three equivalent Mg(2) atoms. is represented by the CIF file [CIF]
data_CaMg
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.645
_cell_length_b   3.645
_cell_length_c   17.054
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   196.180
_cell_formula_units_Z   3
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
  Ca  Ca0  1  0.333  0.667  0.842  1.0
  Ca  Ca1  1  0.000  0.000  0.653  1.0
  Ca  Ca2  1  0.333  0.667  0.172  1.0
  Mg  Mg3  1  0.000  0.000  0.007  1.0
  Mg  Mg4  1  0.333  0.667  0.488  1.0
  Mg  Mg5  1  0.000  0.000  0.339  1.0
[/CIF]
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The material described by MgCa crystallizes in the trigonal P3m1 space group. There are three inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to three equivalent Ca(2), six equivalent Ca(1), and three equivalent Mg(1) atoms to form distorted CaCa9Mg3 cuboctahedra that share corners with six equivalent Ca(3)Ca6Mg6 cuboctahedra, corners with six equivalent Ca(1)Ca9Mg3 cuboctahedra, edges with six equivalent Ca(1)Ca9Mg3 cuboctahedra, edges with six equivalent Ca(2)Ca9Mg3 cuboctahedra,  a faceface with one Ca(3)Ca6Mg6 cuboctahedra, faces with six equivalent Ca(1)Ca9Mg3 cuboctahedra, and faces with six equivalent Ca(2)Ca9Mg3 cuboctahedra. In the second Ca site, Ca(2) is bonded to three equivalent Ca(1), six equivalent Ca(2), and three equivalent Mg(2) atoms to form a mixture of distorted edge, face, and corner-sharing CaCa9Mg3 cuboctahedra. In the third Ca site, Ca(3) is bonded to six equivalent Ca(3), three equivalent Mg(1), and three equivalent Mg(3) atoms to form distorted CaCa6Mg6 cuboctahedra that share corners with six equivalent Ca(3)Ca6Mg6 cuboctahedra, corners with six equivalent Ca(1)Ca9Mg3 cuboctahedra, edges with six equivalent Ca(3)Ca6Mg6 cuboctahedra,  a faceface with one Ca(1)Ca9Mg3 cuboctahedra, and faces with six equivalent Ca(3)Ca6Mg6 cuboctahedra. There are three inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 6-coordinate geometry to three equivalent Ca(1) and three equivalent Ca(3) atoms. In the second Mg site, Mg(2) is bonded in a 6-coordinate geometry to three equivalent Ca(2) and three equivalent Mg(3) atoms. In the third Mg site, Mg(3) is bonded in a 6-coordinate geometry to three equivalent Ca(3) and three equivalent Mg(2) atoms. is represented by the CIF file [CIF]
data_CaMg
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.645
_cell_length_b   3.645
_cell_length_c   17.054
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   196.180
_cell_formula_units_Z   3
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
  Ca  Ca0  1  0.333  0.667  0.842  1.0
  Ca  Ca1  1  0.000  0.000  0.653  1.0
  Ca  Ca2  1  0.333  0.667  0.172  1.0
  Mg  Mg3  1  0.000  0.000  0.007  1.0
  Mg  Mg4  1  0.333  0.667  0.488  1.0
  Mg  Mg5  1  0.000  0.000  0.339  1.0
[/CIF]
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