The structure described by MgCa crystallizes in the orthorhombic Amm2 space group. There are three inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to two equivalent Ca(2), three equivalent Ca(1), three equivalent Mg(1), and four equivalent Mg(2) atoms to form distorted CaCa5Mg7 cuboctahedra that share corners with nine equivalent Ca(1)Ca5Mg7 cuboctahedra; corners with nine equivalent Mg(1)Ca8Mg4 cuboctahedra; edges with four equivalent Ca(2)Ca4Mg8 cuboctahedra; edges with six equivalent Ca(1)Ca5Mg7 cuboctahedra; faces with three equivalent Mg(1)Ca8Mg4 cuboctahedra; faces with four equivalent Ca(2)Ca4Mg8 cuboctahedra; and faces with five Ca(1,1)Ca5Mg7 cuboctahedra. In the second Ca site, Ca(1) is bonded to two equivalent Ca(2), three equivalent Ca(1), three equivalent Mg(1), and four equivalent Mg(2) atoms to form distorted CaCa5Mg7 cuboctahedra that share corners with nine equivalent Ca(1)Ca5Mg7 cuboctahedra; corners with nine equivalent Mg(1)Ca8Mg4 cuboctahedra; edges with four equivalent Ca(2)Ca4Mg8 cuboctahedra; edges with six equivalent Ca(1)Ca5Mg7 cuboctahedra; faces with three equivalent Mg(1)Ca8Mg4 cuboctahedra; faces with four equivalent Ca(2)Ca4Mg8 cuboctahedra; and faces with five Ca(1,1)Ca5Mg7 cuboctahedra. In the third Ca site, Ca(2) is bonded to four Ca(1,1); two equivalent Mg(1); and six equivalent Mg(2) atoms to form distorted CaCa4Mg8 cuboctahedra that share edges with four equivalent Mg(1)Ca8Mg4 cuboctahedra; edges with six equivalent Ca(2)Ca4Mg8 cuboctahedra; edges with eight Ca(1,1)Ca5Mg7 cuboctahedra; faces with two equivalent Ca(2)Ca4Mg8 cuboctahedra; faces with four equivalent Mg(1)Ca8Mg4 cuboctahedra; and faces with eight Ca(1,1)Ca5Mg7 cuboctahedra. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Ca(2); six Ca(1,1); and four equivalent Mg(2) atoms to form distorted MgCa8Mg4 cuboctahedra that share corners with eighteen Ca(1,1)Ca5Mg7 cuboctahedra; edges with four equivalent Ca(2)Ca4Mg8 cuboctahedra; edges with six equivalent Mg(1)Ca8Mg4 cuboctahedra; faces with two equivalent Mg(1)Ca8Mg4 cuboctahedra; faces with four equivalent Ca(2)Ca4Mg8 cuboctahedra; and faces with six Ca(1,1)Ca5Mg7 cuboctahedra. In the second Mg site, Mg(2) is bonded in a 7-coordinate geometry to three equivalent Ca(2); four Ca(1,1); and two equivalent Mg(1) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_CaMg
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.703
_cell_length_b   6.118
_cell_length_c   6.190
_cell_angle_alpha   119.619
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   187.759
_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  0.000  0.668  0.652  1.0
  Ca  Ca1  1  0.000  0.017  0.348  1.0
  Ca  Ca2  1  0.500  0.645  0.000  1.0
  Mg  Mg3  1  0.000  0.327  0.000  1.0
  Mg  Mg4  1  0.500  0.333  0.324  1.0
  Mg  Mg5  1  0.500  0.009  0.676  1.0
[/CIF]
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The structure described by MgCa crystallizes in the orthorhombic Amm2 space group. There are three inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to two equivalent Ca(2), three equivalent Ca(1), three equivalent Mg(1), and four equivalent Mg(2) atoms to form distorted CaCa5Mg7 cuboctahedra that share corners with nine equivalent Ca(1)Ca5Mg7 cuboctahedra; corners with nine equivalent Mg(1)Ca8Mg4 cuboctahedra; edges with four equivalent Ca(2)Ca4Mg8 cuboctahedra; edges with six equivalent Ca(1)Ca5Mg7 cuboctahedra; faces with three equivalent Mg(1)Ca8Mg4 cuboctahedra; faces with four equivalent Ca(2)Ca4Mg8 cuboctahedra; and faces with five Ca(1,1)Ca5Mg7 cuboctahedra. In the second Ca site, Ca(1) is bonded to two equivalent Ca(2), three equivalent Ca(1), three equivalent Mg(1), and four equivalent Mg(2) atoms to form distorted CaCa5Mg7 cuboctahedra that share corners with nine equivalent Ca(1)Ca5Mg7 cuboctahedra; corners with nine equivalent Mg(1)Ca8Mg4 cuboctahedra; edges with four equivalent Ca(2)Ca4Mg8 cuboctahedra; edges with six equivalent Ca(1)Ca5Mg7 cuboctahedra; faces with three equivalent Mg(1)Ca8Mg4 cuboctahedra; faces with four equivalent Ca(2)Ca4Mg8 cuboctahedra; and faces with five Ca(1,1)Ca5Mg7 cuboctahedra. In the third Ca site, Ca(2) is bonded to four Ca(1,1); two equivalent Mg(1); and six equivalent Mg(2) atoms to form distorted CaCa4Mg8 cuboctahedra that share edges with four equivalent Mg(1)Ca8Mg4 cuboctahedra; edges with six equivalent Ca(2)Ca4Mg8 cuboctahedra; edges with eight Ca(1,1)Ca5Mg7 cuboctahedra; faces with two equivalent Ca(2)Ca4Mg8 cuboctahedra; faces with four equivalent Mg(1)Ca8Mg4 cuboctahedra; and faces with eight Ca(1,1)Ca5Mg7 cuboctahedra. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Ca(2); six Ca(1,1); and four equivalent Mg(2) atoms to form distorted MgCa8Mg4 cuboctahedra that share corners with eighteen Ca(1,1)Ca5Mg7 cuboctahedra; edges with four equivalent Ca(2)Ca4Mg8 cuboctahedra; edges with six equivalent Mg(1)Ca8Mg4 cuboctahedra; faces with two equivalent Mg(1)Ca8Mg4 cuboctahedra; faces with four equivalent Ca(2)Ca4Mg8 cuboctahedra; and faces with six Ca(1,1)Ca5Mg7 cuboctahedra. In the second Mg site, Mg(2) is bonded in a 7-coordinate geometry to three equivalent Ca(2); four Ca(1,1); and two equivalent Mg(1) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_CaMg
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.703
_cell_length_b   6.118
_cell_length_c   6.190
_cell_angle_alpha   119.619
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   187.759
_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  0.000  0.668  0.652  1.0
  Ca  Ca1  1  0.000  0.017  0.348  1.0
  Ca  Ca2  1  0.500  0.645  0.000  1.0
  Mg  Mg3  1  0.000  0.327  0.000  1.0
  Mg  Mg4  1  0.500  0.333  0.324  1.0
  Mg  Mg5  1  0.500  0.009  0.676  1.0
[/CIF]
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