The structure described by MgCa3 is Uranium Silicide structured and crystallizes in the cubic Pm-3m space group. Ca(1) is bonded to eight equivalent Ca(1) and four equivalent Mg(1) atoms to form CaCa8Mg4 cuboctahedra that share corners with twelve equivalent Ca(1)Ca8Mg4 cuboctahedra, edges with eight equivalent Mg(1)Ca12 cuboctahedra, edges with sixteen equivalent Ca(1)Ca8Mg4 cuboctahedra, faces with four equivalent Mg(1)Ca12 cuboctahedra, and faces with fourteen equivalent Ca(1)Ca8Mg4 cuboctahedra. Mg(1) is bonded to twelve equivalent Ca(1) atoms to form MgCa12 cuboctahedra that share corners with twelve equivalent Mg(1)Ca12 cuboctahedra, edges with twenty-four equivalent Ca(1)Ca8Mg4 cuboctahedra, faces with six equivalent Mg(1)Ca12 cuboctahedra, and faces with twelve equivalent Ca(1)Ca8Mg4 cuboctahedra. is represented by the CIF file [CIF]
data_Ca3Mg
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.289
_cell_length_b   5.289
_cell_length_c   5.289
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   147.936
_cell_formula_units_Z   1
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  0.500  0.500  0.000  1.0
  Ca  Ca1  1  0.500  0.000  0.500  1.0
  Ca  Ca2  1  0.000  0.500  0.500  1.0
  Mg  Mg3  1  0.000  0.000  0.000  1.0
[/CIF]
.
The structure described by MgCa3 is Uranium Silicide structured and crystallizes in the cubic Pm-3m space group. Ca(1) is bonded to eight equivalent Ca(1) and four equivalent Mg(1) atoms to form CaCa8Mg4 cuboctahedra that share corners with twelve equivalent Ca(1)Ca8Mg4 cuboctahedra, edges with eight equivalent Mg(1)Ca12 cuboctahedra, edges with sixteen equivalent Ca(1)Ca8Mg4 cuboctahedra, faces with four equivalent Mg(1)Ca12 cuboctahedra, and faces with fourteen equivalent Ca(1)Ca8Mg4 cuboctahedra. Mg(1) is bonded to twelve equivalent Ca(1) atoms to form MgCa12 cuboctahedra that share corners with twelve equivalent Mg(1)Ca12 cuboctahedra, edges with twenty-four equivalent Ca(1)Ca8Mg4 cuboctahedra, faces with six equivalent Mg(1)Ca12 cuboctahedra, and faces with twelve equivalent Ca(1)Ca8Mg4 cuboctahedra. is represented by the CIF file [CIF]
data_Ca3Mg
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.289
_cell_length_b   5.289
_cell_length_c   5.289
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   147.936
_cell_formula_units_Z   1
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  0.500  0.500  0.000  1.0
  Ca  Ca1  1  0.500  0.000  0.500  1.0
  Ca  Ca2  1  0.000  0.500  0.500  1.0
  Mg  Mg3  1  0.000  0.000  0.000  1.0
[/CIF]
.