The material structure described by Ca2Mg crystallizes in the hexagonal P-62m space group. There are three inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to two equivalent Ca(2); six Ca(1,1); and four equivalent Mg(1) atoms to form distorted CaCa8Mg4 cuboctahedra that share corners with eighteen Ca(1,1)Ca8Mg4 cuboctahedra; edges with four equivalent Ca(2)Ca6Mg6 cuboctahedra; edges with six equivalent Ca(1)Ca8Mg4 cuboctahedra; faces with four equivalent Ca(2)Ca6Mg6 cuboctahedra; and faces with eight Ca(1,1)Ca8Mg4 cuboctahedra. In the second Ca site, Ca(1) is bonded to two equivalent Ca(2), six equivalent Ca(1), and four equivalent Mg(1) atoms to form distorted CaCa8Mg4 cuboctahedra that share corners with eighteen equivalent Ca(1)Ca8Mg4 cuboctahedra; edges with four equivalent Ca(2)Ca6Mg6 cuboctahedra; edges with six equivalent Ca(1)Ca8Mg4 cuboctahedra; faces with four equivalent Ca(2)Ca6Mg6 cuboctahedra; and faces with eight Ca(1,1)Ca8Mg4 cuboctahedra. In the third Ca site, Ca(2) is bonded to six Ca(1,1) and six equivalent Mg(1) atoms to form CaCa6Mg6 cuboctahedra that share edges with six equivalent Ca(2)Ca6Mg6 cuboctahedra; edges with twelve Ca(1,1)Ca8Mg4 cuboctahedra; faces with two equivalent Ca(2)Ca6Mg6 cuboctahedra; and faces with twelve Ca(1,1)Ca8Mg4 cuboctahedra. Mg(1) is bonded in a 9-coordinate geometry to three equivalent Ca(2) and six Ca(1,1) atoms. is represented by the CIF card [CIF]
data_Ca2Mg
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.372
_cell_length_b   6.372
_cell_length_c   5.969
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   209.881
_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
  Ca  Ca0  1  0.000  0.653  0.500  1.0
  Ca  Ca1  1  0.653  0.000  0.500  1.0
  Ca  Ca2  1  0.347  0.347  0.500  1.0
  Ca  Ca3  1  0.000  0.000  0.000  1.0
  Mg  Mg4  1  0.667  0.333  0.000  1.0
  Mg  Mg5  1  0.333  0.667  0.000  1.0
[/CIF]
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The material structure described by Ca2Mg crystallizes in the hexagonal P-62m space group. There are three inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to two equivalent Ca(2); six Ca(1,1); and four equivalent Mg(1) atoms to form distorted CaCa8Mg4 cuboctahedra that share corners with eighteen Ca(1,1)Ca8Mg4 cuboctahedra; edges with four equivalent Ca(2)Ca6Mg6 cuboctahedra; edges with six equivalent Ca(1)Ca8Mg4 cuboctahedra; faces with four equivalent Ca(2)Ca6Mg6 cuboctahedra; and faces with eight Ca(1,1)Ca8Mg4 cuboctahedra. In the second Ca site, Ca(1) is bonded to two equivalent Ca(2), six equivalent Ca(1), and four equivalent Mg(1) atoms to form distorted CaCa8Mg4 cuboctahedra that share corners with eighteen equivalent Ca(1)Ca8Mg4 cuboctahedra; edges with four equivalent Ca(2)Ca6Mg6 cuboctahedra; edges with six equivalent Ca(1)Ca8Mg4 cuboctahedra; faces with four equivalent Ca(2)Ca6Mg6 cuboctahedra; and faces with eight Ca(1,1)Ca8Mg4 cuboctahedra. In the third Ca site, Ca(2) is bonded to six Ca(1,1) and six equivalent Mg(1) atoms to form CaCa6Mg6 cuboctahedra that share edges with six equivalent Ca(2)Ca6Mg6 cuboctahedra; edges with twelve Ca(1,1)Ca8Mg4 cuboctahedra; faces with two equivalent Ca(2)Ca6Mg6 cuboctahedra; and faces with twelve Ca(1,1)Ca8Mg4 cuboctahedra. Mg(1) is bonded in a 9-coordinate geometry to three equivalent Ca(2) and six Ca(1,1) atoms. is represented by the CIF card [CIF]
data_Ca2Mg
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.372
_cell_length_b   6.372
_cell_length_c   5.969
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   209.881
_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
  Ca  Ca0  1  0.000  0.653  0.500  1.0
  Ca  Ca1  1  0.653  0.000  0.500  1.0
  Ca  Ca2  1  0.347  0.347  0.500  1.0
  Ca  Ca3  1  0.000  0.000  0.000  1.0
  Mg  Mg4  1  0.667  0.333  0.000  1.0
  Mg  Mg5  1  0.333  0.667  0.000  1.0
[/CIF]
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