The material described by Mg3Ca is beta-derived structured and crystallizes in the hexagonal P-6m2 space group. Ca(1) is bonded to six equivalent Ca(1) and six equivalent Mg(2) atoms to form CaCa6Mg6 cuboctahedra that share corners with six equivalent Ca(1)Ca6Mg6 cuboctahedra, corners with twelve equivalent Mg(1)Mg12 cuboctahedra, edges with six equivalent Ca(1)Ca6Mg6 cuboctahedra, edges with twelve equivalent Mg(2)Ca3Mg9 cuboctahedra, faces with two equivalent Mg(1)Mg12 cuboctahedra, faces with six equivalent Ca(1)Ca6Mg6 cuboctahedra, and faces with twelve equivalent Mg(2)Ca3Mg9 cuboctahedra. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to six equivalent Mg(1) and six equivalent Mg(2) atoms to form MgMg12 cuboctahedra that share corners with six equivalent Mg(1)Mg12 cuboctahedra, corners with twelve equivalent Ca(1)Ca6Mg6 cuboctahedra, edges with six equivalent Mg(1)Mg12 cuboctahedra, edges with twelve equivalent Mg(2)Ca3Mg9 cuboctahedra, faces with two equivalent Ca(1)Ca6Mg6 cuboctahedra, faces with six equivalent Mg(1)Mg12 cuboctahedra, and faces with twelve equivalent Mg(2)Ca3Mg9 cuboctahedra. In the second Mg site, Mg(2) is bonded to three equivalent Ca(1), three equivalent Mg(1), and six equivalent Mg(2) atoms to form MgCa3Mg9 cuboctahedra that share corners with eighteen equivalent Mg(2)Ca3Mg9 cuboctahedra, edges with six equivalent Ca(1)Ca6Mg6 cuboctahedra, edges with six equivalent Mg(2)Ca3Mg9 cuboctahedra, edges with six equivalent Mg(1)Mg12 cuboctahedra, faces with six equivalent Ca(1)Ca6Mg6 cuboctahedra, faces with six equivalent Mg(1)Mg12 cuboctahedra, and faces with eight equivalent Mg(2)Ca3Mg9 cuboctahedra. is represented by the CIF file [CIF]
data_CaMg3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.409
_cell_length_b   3.409
_cell_length_c   10.881
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   109.511
_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
  Ca  Ca0  1  0.000  0.000  0.500  1.0
  Mg  Mg1  1  0.000  0.000  0.000  1.0
  Mg  Mg2  1  0.667  0.333  0.765  1.0
  Mg  Mg3  1  0.667  0.333  0.235  1.0
[/CIF]
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The material described by Mg3Ca is beta-derived structured and crystallizes in the hexagonal P-6m2 space group. Ca(1) is bonded to six equivalent Ca(1) and six equivalent Mg(2) atoms to form CaCa6Mg6 cuboctahedra that share corners with six equivalent Ca(1)Ca6Mg6 cuboctahedra, corners with twelve equivalent Mg(1)Mg12 cuboctahedra, edges with six equivalent Ca(1)Ca6Mg6 cuboctahedra, edges with twelve equivalent Mg(2)Ca3Mg9 cuboctahedra, faces with two equivalent Mg(1)Mg12 cuboctahedra, faces with six equivalent Ca(1)Ca6Mg6 cuboctahedra, and faces with twelve equivalent Mg(2)Ca3Mg9 cuboctahedra. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to six equivalent Mg(1) and six equivalent Mg(2) atoms to form MgMg12 cuboctahedra that share corners with six equivalent Mg(1)Mg12 cuboctahedra, corners with twelve equivalent Ca(1)Ca6Mg6 cuboctahedra, edges with six equivalent Mg(1)Mg12 cuboctahedra, edges with twelve equivalent Mg(2)Ca3Mg9 cuboctahedra, faces with two equivalent Ca(1)Ca6Mg6 cuboctahedra, faces with six equivalent Mg(1)Mg12 cuboctahedra, and faces with twelve equivalent Mg(2)Ca3Mg9 cuboctahedra. In the second Mg site, Mg(2) is bonded to three equivalent Ca(1), three equivalent Mg(1), and six equivalent Mg(2) atoms to form MgCa3Mg9 cuboctahedra that share corners with eighteen equivalent Mg(2)Ca3Mg9 cuboctahedra, edges with six equivalent Ca(1)Ca6Mg6 cuboctahedra, edges with six equivalent Mg(2)Ca3Mg9 cuboctahedra, edges with six equivalent Mg(1)Mg12 cuboctahedra, faces with six equivalent Ca(1)Ca6Mg6 cuboctahedra, faces with six equivalent Mg(1)Mg12 cuboctahedra, and faces with eight equivalent Mg(2)Ca3Mg9 cuboctahedra. is represented by the CIF file [CIF]
data_CaMg3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.409
_cell_length_b   3.409
_cell_length_c   10.881
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   109.511
_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
  Ca  Ca0  1  0.000  0.000  0.500  1.0
  Mg  Mg1  1  0.000  0.000  0.000  1.0
  Mg  Mg2  1  0.667  0.333  0.765  1.0
  Mg  Mg3  1  0.667  0.333  0.235  1.0
[/CIF]
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