The compound described by MgCa crystallizes in the monoclinic C2 space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to four equivalent Ca(2), two equivalent Mg(2), and six equivalent Mg(1) atoms to form distorted CaCa4Mg8 cuboctahedra that share corners with six equivalent Ca(1)Ca4Mg8 cuboctahedra, edges with six equivalent Ca(1)Ca4Mg8 cuboctahedra, edges with eight equivalent Ca(2)Ca5Mg7 cuboctahedra, and faces with eight equivalent Ca(2)Ca5Mg7 cuboctahedra. In the second Ca site, Ca(2) is bonded to two equivalent Ca(1), three equivalent Ca(2), three equivalent Mg(2), and four equivalent Mg(1) atoms to form distorted CaCa5Mg7 cuboctahedra that share corners with twelve equivalent Ca(2)Ca5Mg7 cuboctahedra, edges with four equivalent Ca(1)Ca4Mg8 cuboctahedra, edges with six equivalent Ca(2)Ca5Mg7 cuboctahedra, faces with four equivalent Ca(1)Ca4Mg8 cuboctahedra, and faces with four equivalent Ca(2)Ca5Mg7 cuboctahedra. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 7-coordinate geometry to three equivalent Ca(1) and four equivalent Ca(2) atoms. In the second Mg site, Mg(2) is bonded in a 8-coordinate geometry to two equivalent Ca(1) and six equivalent Ca(2) atoms. is represented by the CIF file [CIF]
data_CaMg
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.137
_cell_length_b   6.137
_cell_length_c   6.602
_cell_angle_alpha   66.008
_cell_angle_beta   66.008
_cell_angle_gamma   60.232
_symmetry_Int_Tables_number   1
_cell_volume   190.474
_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  0.354  0.646  0.000  1.0
  Ca  Ca1  1  0.155  0.168  0.509  1.0
  Ca  Ca2  1  0.832  0.845  0.491  1.0
  Mg  Mg3  1  0.660  0.003  0.997  1.0
  Mg  Mg4  1  0.997  0.340  0.003  1.0
  Mg  Mg5  1  0.502  0.498  0.500  1.0
[/CIF]
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The compound described by MgCa crystallizes in the monoclinic C2 space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to four equivalent Ca(2), two equivalent Mg(2), and six equivalent Mg(1) atoms to form distorted CaCa4Mg8 cuboctahedra that share corners with six equivalent Ca(1)Ca4Mg8 cuboctahedra, edges with six equivalent Ca(1)Ca4Mg8 cuboctahedra, edges with eight equivalent Ca(2)Ca5Mg7 cuboctahedra, and faces with eight equivalent Ca(2)Ca5Mg7 cuboctahedra. In the second Ca site, Ca(2) is bonded to two equivalent Ca(1), three equivalent Ca(2), three equivalent Mg(2), and four equivalent Mg(1) atoms to form distorted CaCa5Mg7 cuboctahedra that share corners with twelve equivalent Ca(2)Ca5Mg7 cuboctahedra, edges with four equivalent Ca(1)Ca4Mg8 cuboctahedra, edges with six equivalent Ca(2)Ca5Mg7 cuboctahedra, faces with four equivalent Ca(1)Ca4Mg8 cuboctahedra, and faces with four equivalent Ca(2)Ca5Mg7 cuboctahedra. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 7-coordinate geometry to three equivalent Ca(1) and four equivalent Ca(2) atoms. In the second Mg site, Mg(2) is bonded in a 8-coordinate geometry to two equivalent Ca(1) and six equivalent Ca(2) atoms. is represented by the CIF file [CIF]
data_CaMg
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.137
_cell_length_b   6.137
_cell_length_c   6.602
_cell_angle_alpha   66.008
_cell_angle_beta   66.008
_cell_angle_gamma   60.232
_symmetry_Int_Tables_number   1
_cell_volume   190.474
_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  0.354  0.646  0.000  1.0
  Ca  Ca1  1  0.155  0.168  0.509  1.0
  Ca  Ca2  1  0.832  0.845  0.491  1.0
  Mg  Mg3  1  0.660  0.003  0.997  1.0
  Mg  Mg4  1  0.997  0.340  0.003  1.0
  Mg  Mg5  1  0.502  0.498  0.500  1.0
[/CIF]
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