The material described by Ca2Mg crystallizes in the orthorhombic Amm2 space group. There are four inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to two equivalent Ca(1), two equivalent Ca(2), two equivalent Ca(3), four equivalent Ca(4), and two equivalent Mg(1) atoms to form distorted CaCa10Mg2 cuboctahedra that share corners with six equivalent Ca(1)Ca10Mg2 cuboctahedra, corners with six equivalent Ca(3)Ca6Mg6 cuboctahedra, corners with six equivalent Ca(2)Ca8Mg4 cuboctahedra, edges with three equivalent Ca(3)Ca6Mg6 cuboctahedra, edges with three equivalent Ca(2)Ca8Mg4 cuboctahedra, edges with four equivalent Ca(4)Ca8Mg4 cuboctahedra, faces with two equivalent Ca(3)Ca6Mg6 cuboctahedra, faces with two equivalent Ca(2)Ca8Mg4 cuboctahedra, faces with four equivalent Ca(1)Ca10Mg2 cuboctahedra, and faces with four equivalent Ca(4)Ca8Mg4 cuboctahedra. In the second Ca site, Ca(2) is bonded to two equivalent Ca(1), two equivalent Ca(2), two equivalent Ca(3), two equivalent Ca(4), and four equivalent Mg(2) atoms to form distorted CaCa8Mg4 cuboctahedra that share corners with six equivalent Ca(1)Ca10Mg2 cuboctahedra, corners with six equivalent Ca(3)Ca6Mg6 cuboctahedra, corners with six equivalent Ca(2)Ca8Mg4 cuboctahedra, edges with three equivalent Ca(1)Ca10Mg2 cuboctahedra, edges with three equivalent Ca(3)Ca6Mg6 cuboctahedra, faces with two equivalent Ca(1)Ca10Mg2 cuboctahedra, faces with two equivalent Ca(3)Ca6Mg6 cuboctahedra, faces with four equivalent Ca(2)Ca8Mg4 cuboctahedra, and faces with six equivalent Ca(4)Ca8Mg4 cuboctahedra. In the third Ca site, Ca(3) is bonded to two equivalent Ca(1), two equivalent Ca(2), two equivalent Ca(3), two equivalent Mg(2), and four equivalent Mg(1) atoms to form distorted CaCa6Mg6 cuboctahedra that share corners with six equivalent Ca(1)Ca10Mg2 cuboctahedra, corners with six equivalent Ca(3)Ca6Mg6 cuboctahedra, corners with six equivalent Ca(2)Ca8Mg4 cuboctahedra, edges with three equivalent Ca(1)Ca10Mg2 cuboctahedra, edges with three equivalent Ca(2)Ca8Mg4 cuboctahedra, edges with eight equivalent Ca(4)Ca8Mg4 cuboctahedra, faces with two equivalent Ca(1)Ca10Mg2 cuboctahedra, faces with two equivalent Ca(2)Ca8Mg4 cuboctahedra, faces with two equivalent Ca(4)Ca8Mg4 cuboctahedra, and faces with four equivalent Ca(3)Ca6Mg6 cuboctahedra. In the fourth Ca site, Ca(4) is bonded to two equivalent Ca(2), two equivalent Ca(4), four equivalent Ca(1), two equivalent Mg(1), and two equivalent Mg(2) atoms to form CaCa8Mg4 cuboctahedra that share corners with six equivalent Ca(4)Ca8Mg4 cuboctahedra, edges with four equivalent Ca(1)Ca10Mg2 cuboctahedra, edges with eight equivalent Ca(3)Ca6Mg6 cuboctahedra, faces with two equivalent Ca(3)Ca6Mg6 cuboctahedra, faces with four equivalent Ca(1)Ca10Mg2 cuboctahedra, faces with four equivalent Ca(4)Ca8Mg4 cuboctahedra, and faces with six equivalent Ca(2)Ca8Mg4 cuboctahedra. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 8-coordinate geometry to two equivalent Ca(1), two equivalent Ca(4), and four equivalent Ca(3) atoms. In the second Mg site, Mg(2) is bonded in a 8-coordinate geometry to two equivalent Ca(3), two equivalent Ca(4), and four equivalent Ca(2) atoms. is represented by the CIF card [CIF]
data_Ca2Mg
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.771
_cell_length_b   5.875
_cell_length_c   9.794
_cell_angle_alpha   90.000
_cell_angle_beta   101.100
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   212.951
_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  0.003  0.000  0.005  1.0
  Ca  Ca1  1  0.331  0.000  0.661  1.0
  Ca  Ca2  1  0.666  0.000  0.332  1.0
  Ca  Ca3  1  0.445  0.500  0.890  1.0
  Mg  Mg4  1  0.112  0.500  0.225  1.0
  Mg  Mg5  1  0.777  0.500  0.554  1.0
[/CIF]
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The material described by Ca2Mg crystallizes in the orthorhombic Amm2 space group. There are four inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to two equivalent Ca(1), two equivalent Ca(2), two equivalent Ca(3), four equivalent Ca(4), and two equivalent Mg(1) atoms to form distorted CaCa10Mg2 cuboctahedra that share corners with six equivalent Ca(1)Ca10Mg2 cuboctahedra, corners with six equivalent Ca(3)Ca6Mg6 cuboctahedra, corners with six equivalent Ca(2)Ca8Mg4 cuboctahedra, edges with three equivalent Ca(3)Ca6Mg6 cuboctahedra, edges with three equivalent Ca(2)Ca8Mg4 cuboctahedra, edges with four equivalent Ca(4)Ca8Mg4 cuboctahedra, faces with two equivalent Ca(3)Ca6Mg6 cuboctahedra, faces with two equivalent Ca(2)Ca8Mg4 cuboctahedra, faces with four equivalent Ca(1)Ca10Mg2 cuboctahedra, and faces with four equivalent Ca(4)Ca8Mg4 cuboctahedra. In the second Ca site, Ca(2) is bonded to two equivalent Ca(1), two equivalent Ca(2), two equivalent Ca(3), two equivalent Ca(4), and four equivalent Mg(2) atoms to form distorted CaCa8Mg4 cuboctahedra that share corners with six equivalent Ca(1)Ca10Mg2 cuboctahedra, corners with six equivalent Ca(3)Ca6Mg6 cuboctahedra, corners with six equivalent Ca(2)Ca8Mg4 cuboctahedra, edges with three equivalent Ca(1)Ca10Mg2 cuboctahedra, edges with three equivalent Ca(3)Ca6Mg6 cuboctahedra, faces with two equivalent Ca(1)Ca10Mg2 cuboctahedra, faces with two equivalent Ca(3)Ca6Mg6 cuboctahedra, faces with four equivalent Ca(2)Ca8Mg4 cuboctahedra, and faces with six equivalent Ca(4)Ca8Mg4 cuboctahedra. In the third Ca site, Ca(3) is bonded to two equivalent Ca(1), two equivalent Ca(2), two equivalent Ca(3), two equivalent Mg(2), and four equivalent Mg(1) atoms to form distorted CaCa6Mg6 cuboctahedra that share corners with six equivalent Ca(1)Ca10Mg2 cuboctahedra, corners with six equivalent Ca(3)Ca6Mg6 cuboctahedra, corners with six equivalent Ca(2)Ca8Mg4 cuboctahedra, edges with three equivalent Ca(1)Ca10Mg2 cuboctahedra, edges with three equivalent Ca(2)Ca8Mg4 cuboctahedra, edges with eight equivalent Ca(4)Ca8Mg4 cuboctahedra, faces with two equivalent Ca(1)Ca10Mg2 cuboctahedra, faces with two equivalent Ca(2)Ca8Mg4 cuboctahedra, faces with two equivalent Ca(4)Ca8Mg4 cuboctahedra, and faces with four equivalent Ca(3)Ca6Mg6 cuboctahedra. In the fourth Ca site, Ca(4) is bonded to two equivalent Ca(2), two equivalent Ca(4), four equivalent Ca(1), two equivalent Mg(1), and two equivalent Mg(2) atoms to form CaCa8Mg4 cuboctahedra that share corners with six equivalent Ca(4)Ca8Mg4 cuboctahedra, edges with four equivalent Ca(1)Ca10Mg2 cuboctahedra, edges with eight equivalent Ca(3)Ca6Mg6 cuboctahedra, faces with two equivalent Ca(3)Ca6Mg6 cuboctahedra, faces with four equivalent Ca(1)Ca10Mg2 cuboctahedra, faces with four equivalent Ca(4)Ca8Mg4 cuboctahedra, and faces with six equivalent Ca(2)Ca8Mg4 cuboctahedra. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 8-coordinate geometry to two equivalent Ca(1), two equivalent Ca(4), and four equivalent Ca(3) atoms. In the second Mg site, Mg(2) is bonded in a 8-coordinate geometry to two equivalent Ca(3), two equivalent Ca(4), and four equivalent Ca(2) atoms. is represented by the CIF card [CIF]
data_Ca2Mg
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.771
_cell_length_b   5.875
_cell_length_c   9.794
_cell_angle_alpha   90.000
_cell_angle_beta   101.100
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   212.951
_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  0.003  0.000  0.005  1.0
  Ca  Ca1  1  0.331  0.000  0.661  1.0
  Ca  Ca2  1  0.666  0.000  0.332  1.0
  Ca  Ca3  1  0.445  0.500  0.890  1.0
  Mg  Mg4  1  0.112  0.500  0.225  1.0
  Mg  Mg5  1  0.777  0.500  0.554  1.0
[/CIF]
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