The material described by Ca2Mg crystallizes in the orthorhombic Cmcm space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to two equivalent Ca(2), four equivalent Ca(1), and six equivalent Mg(1) atoms to form distorted CaCa6Mg6 cuboctahedra that share corners with six equivalent Ca(1)Ca6Mg6 cuboctahedra, corners with six equivalent Ca(2)Ca8Mg4 cuboctahedra, edges with eleven equivalent Ca(2)Ca8Mg4 cuboctahedra, faces with four equivalent Ca(2)Ca8Mg4 cuboctahedra, and faces with ten equivalent Ca(1)Ca6Mg6 cuboctahedra. In the second Ca site, Ca(2) is bonded to two equivalent Ca(1), six equivalent Ca(2), and four equivalent Mg(1) atoms to form distorted CaCa8Mg4 cuboctahedra that share corners with six equivalent Ca(1)Ca6Mg6 cuboctahedra, corners with six equivalent Ca(2)Ca8Mg4 cuboctahedra, edges with four equivalent Ca(2)Ca8Mg4 cuboctahedra, edges with eleven equivalent Ca(1)Ca6Mg6 cuboctahedra, faces with four equivalent Ca(1)Ca6Mg6 cuboctahedra, and faces with eight equivalent Ca(2)Ca8Mg4 cuboctahedra. Mg(1) is bonded in a 10-coordinate geometry to four equivalent Ca(2) and six equivalent Ca(1) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_Ca2Mg
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.480
_cell_length_b   9.480
_cell_length_c   5.988
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   157.180
_symmetry_Int_Tables_number   1
_cell_volume   208.707
_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  0.446  0.554  0.250  1.0
  Ca  Ca1  1  0.771  0.229  0.250  1.0
  Ca  Ca2  1  0.229  0.771  0.750  1.0
  Ca  Ca3  1  0.554  0.446  0.750  1.0
  Mg  Mg4  1  0.111  0.889  0.250  1.0
  Mg  Mg5  1  0.889  0.111  0.750  1.0
[/CIF]
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The material described by Ca2Mg crystallizes in the orthorhombic Cmcm space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to two equivalent Ca(2), four equivalent Ca(1), and six equivalent Mg(1) atoms to form distorted CaCa6Mg6 cuboctahedra that share corners with six equivalent Ca(1)Ca6Mg6 cuboctahedra, corners with six equivalent Ca(2)Ca8Mg4 cuboctahedra, edges with eleven equivalent Ca(2)Ca8Mg4 cuboctahedra, faces with four equivalent Ca(2)Ca8Mg4 cuboctahedra, and faces with ten equivalent Ca(1)Ca6Mg6 cuboctahedra. In the second Ca site, Ca(2) is bonded to two equivalent Ca(1), six equivalent Ca(2), and four equivalent Mg(1) atoms to form distorted CaCa8Mg4 cuboctahedra that share corners with six equivalent Ca(1)Ca6Mg6 cuboctahedra, corners with six equivalent Ca(2)Ca8Mg4 cuboctahedra, edges with four equivalent Ca(2)Ca8Mg4 cuboctahedra, edges with eleven equivalent Ca(1)Ca6Mg6 cuboctahedra, faces with four equivalent Ca(1)Ca6Mg6 cuboctahedra, and faces with eight equivalent Ca(2)Ca8Mg4 cuboctahedra. Mg(1) is bonded in a 10-coordinate geometry to four equivalent Ca(2) and six equivalent Ca(1) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_Ca2Mg
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.480
_cell_length_b   9.480
_cell_length_c   5.988
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   157.180
_symmetry_Int_Tables_number   1
_cell_volume   208.707
_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  0.446  0.554  0.250  1.0
  Ca  Ca1  1  0.771  0.229  0.250  1.0
  Ca  Ca2  1  0.229  0.771  0.750  1.0
  Ca  Ca3  1  0.554  0.446  0.750  1.0
  Mg  Mg4  1  0.111  0.889  0.250  1.0
  Mg  Mg5  1  0.889  0.111  0.750  1.0
[/CIF]
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