data_Ca2Mg4Cu
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.08
_cell_length_b   9.08
_cell_length_c   9.08
_cell_angle_alpha   148.42
_cell_angle_beta   148.42
_cell_angle_gamma   45.26
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Ca2Mg4Cu
_chemical_formula_sum   'Ca2 Mg4 Cu1'
_cell_volume   204.39
_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  0.0  0.0  0.81  1.0
  Ca  Ca1  1  0.0  0.0  0.94  1.0
  Mg  Mg3  1  0.47  0.0  0.0  1.0
  Mg  Mg4  1  0.0  0.47  0.0  1.0
  Mg  Mg5  1  0.0  0.0  0.49  1.0
  Mg  Mg6  1  0.0  0.0  0.27  1.0
  Cu  Cu2  1  0.0  0.0  0.0  1.0

data_Ca2Mg4Cu
_symmetry_space_group_name_H-M   Cm
_cell_length_a   6.99
_cell_length_b   6.99
_cell_length_c   9.08
_cell_angle_alpha   90.0
_cell_angle_beta   112.63
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   Ca2Mg4Cu
_chemical_formula_sum   'Ca4 Mg8 Cu2'
_cell_volume   408.78
_cell_formula_units_Z   2
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  'x, -y, z'
  3  'x+1/2, y+1/2, z'
  4  'x+1/2, -y+1/2, 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  2  0.31  0.5  0.81  1.0
  Ca  Ca1  2  0.44  0.5  0.94  1.0
  Mg  Mg2  4  0.27  0.27  0.53  1.0
  Mg  Mg3  2  0.27  0.0  0.27  1.0
  Mg  Mg4  2  0.49  0.0  0.49  1.0
  Cu  Cu5  2  0.0  0.0  0.0  1.0

Ca Ca Mg Mg Mg Mg Cu
Ca Ca Mg Mg Mg Mg Cu 0 1 o o o 0 2 o o + 0 3 o o + 1 6 o o + 2 4 o o - 2 4 + o o 2 5 + o o 3 5 o + o 3 4 o + o 3 4 o o - 4 5 o o o 
Ca2Mg4Cu crystallizes in the monoclinic Cm space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 4-coordinate geometry to one Ca(2), one Mg(2), and two equivalent Mg(1) atoms. The Ca(1)-Ca(2) bond length is 1.17 Å. The Ca(1)-Mg(2) bond length is 2.96 Å. Both Ca(1)-Mg(1) bond lengths are 2.95 Å. In the second Ca site, Ca(2) is bonded in a single-bond geometry to one Ca(1) and one Cu(1) atom. The Ca(2)-Cu(1) bond length is 0.53 Å. There are three inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 3-coordinate geometry to one Ca(1) and two equivalent Mg(2) atoms. There is one shorter (2.46 Å) and one longer (2.54 Å) Mg(1)-Mg(2) bond length. In the second Mg site, Mg(2) is bonded to one Ca(1), one Mg(3), and four equivalent Mg(1) atoms to form distorted corner-sharing MgCaMg5 octahedra. The corner-sharing octahedral tilt angles are 17°. The Mg(2)-Mg(3) bond length is 1.99 Å. In the third Mg site, Mg(3) is bonded in a distorted linear geometry to one Mg(2) and one Cu(1) atom. The Mg(3)-Cu(1) bond length is 2.43 Å. Cu(1) is bonded in a distorted linear geometry to one Ca(2) and one Mg(3) atom.