The compound described by MgCu2O4 crystallizes in the triclinic P1 space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 5-coordinate geometry to one O(4), two equivalent O(6), and two equivalent O(7) atoms. In the second Mg site, Mg(2) is bonded in a 5-coordinate geometry to one O(1), two equivalent O(5), and two equivalent O(8) atoms. There are four inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one O(2), two equivalent O(4), and two equivalent O(5) atoms to form CuO5 square pyramids that share corners with two equivalent Cu(2)O6 octahedra, corners with two equivalent Cu(3)O6 octahedra, and edges with two equivalent Cu(1)O5 square pyramids. The corner-sharing octahedral tilt angles range from 49-57°. In the second Cu site, Cu(2) is bonded to one O(4), one O(8), two equivalent O(3), and two equivalent O(6) atoms to form distorted CuO6 octahedra that share corners with two equivalent Cu(1)O5 square pyramids, corners with two equivalent Cu(4)O5 square pyramids, edges with two equivalent Cu(2)O6 octahedra, and edges with two equivalent Cu(3)O6 octahedra. In the third Cu site, Cu(3) is bonded to one O(1), one O(6), two equivalent O(2), and two equivalent O(8) atoms to form CuO6 octahedra that share corners with two equivalent Cu(1)O5 square pyramids, corners with two equivalent Cu(4)O5 square pyramids, edges with two equivalent Cu(2)O6 octahedra, and edges with two equivalent Cu(3)O6 octahedra. In the fourth Cu site, Cu(4) is bonded to one O(3), two equivalent O(1), and two equivalent O(7) atoms to form CuO5 square pyramids that share corners with two equivalent Cu(2)O6 octahedra, corners with two equivalent Cu(3)O6 octahedra, and edges with two equivalent Cu(4)O5 square pyramids. The corner-sharing octahedral tilt angles range from 49-56°. There are eight inequivalent O sites. In the first O site, O(1) is bonded to one Mg(2), one Cu(3), and two equivalent Cu(4) atoms to form distorted OMgCu3 trigonal pyramids that share  a cornercorner with one O(6)Mg2Cu3 trigonal bipyramid, corners with two equivalent O(1)MgCu3 trigonal pyramids, and edges with two equivalent O(8)Mg2Cu3 trigonal bipyramids. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Cu(1) and two equivalent Cu(3) atoms. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Cu(4) and two equivalent Cu(2) atoms. In the fourth O site, O(4) is bonded to one Mg(1), one Cu(2), and two equivalent Cu(1) atoms to form distorted OMgCu3 trigonal pyramids that share  a cornercorner with one O(8)Mg2Cu3 trigonal bipyramid, corners with two equivalent O(4)MgCu3 trigonal pyramids, and edges with two equivalent O(6)Mg2Cu3 trigonal bipyramids. In the fifth O site, O(5) is bonded in a rectangular see-saw-like geometry to two equivalent Mg(2) and two equivalent Cu(1) atoms. In the sixth O site, O(6) is bonded to two equivalent Mg(1), one Cu(3), and two equivalent Cu(2) atoms to form distorted OMg2Cu3 trigonal bipyramids that share  a cornercorner with one O(1)MgCu3 trigonal pyramid, edges with two equivalent O(6)Mg2Cu3 trigonal bipyramids, edges with two equivalent O(8)Mg2Cu3 trigonal bipyramids, and edges with two equivalent O(4)MgCu3 trigonal pyramids. In the seventh O site, O(7) is bonded in a rectangular see-saw-like geometry to two equivalent Mg(1) and two equivalent Cu(4) atoms. In the eighth O site, O(8) is bonded to two equivalent Mg(2), one Cu(2), and two equivalent Cu(3) atoms to form distorted OMg2Cu3 trigonal bipyramids that share  a cornercorner with one O(4)MgCu3 trigonal pyramid, edges with two equivalent O(6)Mg2Cu3 trigonal bipyramids, edges with two equivalent O(8)Mg2Cu3 trigonal bipyramids, and edges with two equivalent O(1)MgCu3 trigonal pyramids. is represented by the Crystallographic Information File (CIF) [CIF]
data_Mg(CuO2)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   2.880
_cell_length_b   7.899
_cell_length_c   7.328
_cell_angle_alpha   69.852
_cell_angle_beta   78.874
_cell_angle_gamma   79.857
_symmetry_Int_Tables_number   1
_cell_volume   152.451
_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
  Mg  Mg0  1  0.323  0.159  0.208  1.0
  Mg  Mg1  1  0.681  0.820  0.823  1.0
  Cu  Cu2  1  0.614  0.180  0.606  1.0
  Cu  Cu3  1  0.144  0.512  0.196  1.0
  Cu  Cu4  1  0.856  0.466  0.839  1.0
  Cu  Cu5  1  0.389  0.798  0.426  1.0
  O  O6  1  0.865  0.680  0.592  1.0
  O  O7  1  0.447  0.315  0.812  1.0
  O  O8  1  0.553  0.660  0.227  1.0
  O  O9  1  0.138  0.298  0.441  1.0
  O  O10  1  0.136  0.012  0.727  1.0
  O  O11  1  0.773  0.347  0.124  1.0
  O  O12  1  0.868  0.968  0.303  1.0
  O  O13  1  0.230  0.631  0.909  1.0
[/CIF]
.
The compound described by MgCu2O4 crystallizes in the triclinic P1 space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 5-coordinate geometry to one O(4), two equivalent O(6), and two equivalent O(7) atoms. In the second Mg site, Mg(2) is bonded in a 5-coordinate geometry to one O(1), two equivalent O(5), and two equivalent O(8) atoms. There are four inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one O(2), two equivalent O(4), and two equivalent O(5) atoms to form CuO5 square pyramids that share corners with two equivalent Cu(2)O6 octahedra, corners with two equivalent Cu(3)O6 octahedra, and edges with two equivalent Cu(1)O5 square pyramids. The corner-sharing octahedral tilt angles range from 49-57°. In the second Cu site, Cu(2) is bonded to one O(4), one O(8), two equivalent O(3), and two equivalent O(6) atoms to form distorted CuO6 octahedra that share corners with two equivalent Cu(1)O5 square pyramids, corners with two equivalent Cu(4)O5 square pyramids, edges with two equivalent Cu(2)O6 octahedra, and edges with two equivalent Cu(3)O6 octahedra. In the third Cu site, Cu(3) is bonded to one O(1), one O(6), two equivalent O(2), and two equivalent O(8) atoms to form CuO6 octahedra that share corners with two equivalent Cu(1)O5 square pyramids, corners with two equivalent Cu(4)O5 square pyramids, edges with two equivalent Cu(2)O6 octahedra, and edges with two equivalent Cu(3)O6 octahedra. In the fourth Cu site, Cu(4) is bonded to one O(3), two equivalent O(1), and two equivalent O(7) atoms to form CuO5 square pyramids that share corners with two equivalent Cu(2)O6 octahedra, corners with two equivalent Cu(3)O6 octahedra, and edges with two equivalent Cu(4)O5 square pyramids. The corner-sharing octahedral tilt angles range from 49-56°. There are eight inequivalent O sites. In the first O site, O(1) is bonded to one Mg(2), one Cu(3), and two equivalent Cu(4) atoms to form distorted OMgCu3 trigonal pyramids that share  a cornercorner with one O(6)Mg2Cu3 trigonal bipyramid, corners with two equivalent O(1)MgCu3 trigonal pyramids, and edges with two equivalent O(8)Mg2Cu3 trigonal bipyramids. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Cu(1) and two equivalent Cu(3) atoms. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Cu(4) and two equivalent Cu(2) atoms. In the fourth O site, O(4) is bonded to one Mg(1), one Cu(2), and two equivalent Cu(1) atoms to form distorted OMgCu3 trigonal pyramids that share  a cornercorner with one O(8)Mg2Cu3 trigonal bipyramid, corners with two equivalent O(4)MgCu3 trigonal pyramids, and edges with two equivalent O(6)Mg2Cu3 trigonal bipyramids. In the fifth O site, O(5) is bonded in a rectangular see-saw-like geometry to two equivalent Mg(2) and two equivalent Cu(1) atoms. In the sixth O site, O(6) is bonded to two equivalent Mg(1), one Cu(3), and two equivalent Cu(2) atoms to form distorted OMg2Cu3 trigonal bipyramids that share  a cornercorner with one O(1)MgCu3 trigonal pyramid, edges with two equivalent O(6)Mg2Cu3 trigonal bipyramids, edges with two equivalent O(8)Mg2Cu3 trigonal bipyramids, and edges with two equivalent O(4)MgCu3 trigonal pyramids. In the seventh O site, O(7) is bonded in a rectangular see-saw-like geometry to two equivalent Mg(1) and two equivalent Cu(4) atoms. In the eighth O site, O(8) is bonded to two equivalent Mg(2), one Cu(2), and two equivalent Cu(3) atoms to form distorted OMg2Cu3 trigonal bipyramids that share  a cornercorner with one O(4)MgCu3 trigonal pyramid, edges with two equivalent O(6)Mg2Cu3 trigonal bipyramids, edges with two equivalent O(8)Mg2Cu3 trigonal bipyramids, and edges with two equivalent O(1)MgCu3 trigonal pyramids. is represented by the Crystallographic Information File (CIF) [CIF]
data_Mg(CuO2)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   2.880
_cell_length_b   7.899
_cell_length_c   7.328
_cell_angle_alpha   69.852
_cell_angle_beta   78.874
_cell_angle_gamma   79.857
_symmetry_Int_Tables_number   1
_cell_volume   152.451
_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
  Mg  Mg0  1  0.323  0.159  0.208  1.0
  Mg  Mg1  1  0.681  0.820  0.823  1.0
  Cu  Cu2  1  0.614  0.180  0.606  1.0
  Cu  Cu3  1  0.144  0.512  0.196  1.0
  Cu  Cu4  1  0.856  0.466  0.839  1.0
  Cu  Cu5  1  0.389  0.798  0.426  1.0
  O  O6  1  0.865  0.680  0.592  1.0
  O  O7  1  0.447  0.315  0.812  1.0
  O  O8  1  0.553  0.660  0.227  1.0
  O  O9  1  0.138  0.298  0.441  1.0
  O  O10  1  0.136  0.012  0.727  1.0
  O  O11  1  0.773  0.347  0.124  1.0
  O  O12  1  0.868  0.968  0.303  1.0
  O  O13  1  0.230  0.631  0.909  1.0
[/CIF]
.