The material described by MgCu2O4 is Spinel-like structured and crystallizes in the monoclinic Cm space group. There are six inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to one O(13), one O(3), and two equivalent O(1) atoms to form MgO4 tetrahedra that share  a cornercorner with one Mg(6)O6 octahedra, corners with two equivalent Mg(3)O6 octahedra, corners with two equivalent Cu(6)O6 octahedra, corners with three equivalent Cu(3)O6 octahedra, and corners with four equivalent Cu(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 57-60°. In the second Mg site, Mg(2) is bonded to one O(5), one O(9), two equivalent O(4), and two equivalent O(7) atoms to form MgO6 octahedra that share corners with three equivalent Cu(2)O4 tetrahedra, corners with three equivalent Cu(7)O4 tetrahedra,  an edgeedge with one Mg(3)O6 octahedra,  an edgeedge with one Mg(5)O6 octahedra, edges with two equivalent Cu(1)O6 octahedra, and edges with two equivalent Cu(4)O6 octahedra. In the third Mg site, Mg(3) is bonded to one O(2), one O(8), two equivalent O(1), and two equivalent O(7) atoms to form MgO6 octahedra that share  a cornercorner with one Cu(2)O4 tetrahedra,  a cornercorner with one Cu(9)O4 tetrahedra, corners with two equivalent Mg(1)O4 tetrahedra, corners with two equivalent Cu(7)O4 tetrahedra,  an edgeedge with one Mg(2)O6 octahedra,  an edgeedge with one Cu(3)O6 octahedra, and edges with four equivalent Cu(1)O6 octahedra. In the fourth Mg site, Mg(4) is bonded to one O(11), one O(15), two equivalent O(10), and two equivalent O(12) atoms to form MgO6 octahedra that share corners with three equivalent Cu(5)O4 tetrahedra, corners with three equivalent Cu(8)O4 tetrahedra,  an edgeedge with one Mg(5)O6 octahedra,  an edgeedge with one Mg(6)O6 octahedra, edges with two equivalent Cu(4)O6 octahedra, and edges with two equivalent Cu(6)O6 octahedra. In the fifth Mg site, Mg(5) is bonded to one O(14), one O(6), two equivalent O(12), and two equivalent O(4) atoms to form MgO6 octahedra that share  a cornercorner with one Cu(5)O4 tetrahedra,  a cornercorner with one Cu(7)O4 tetrahedra, corners with two equivalent Cu(2)O4 tetrahedra, corners with two equivalent Cu(8)O4 tetrahedra,  an edgeedge with one Mg(2)O6 octahedra,  an edgeedge with one Mg(4)O6 octahedra, and edges with four equivalent Cu(4)O6 octahedra. In the sixth Mg site, Mg(6) is bonded to one O(13), one O(18), two equivalent O(10), and two equivalent O(17) atoms to form MgO6 octahedra that share  a cornercorner with one Mg(1)O4 tetrahedra,  a cornercorner with one Cu(8)O4 tetrahedra, corners with two equivalent Cu(5)O4 tetrahedra, corners with two equivalent Cu(9)O4 tetrahedra,  an edgeedge with one Mg(4)O6 octahedra,  an edgeedge with one Cu(3)O6 octahedra, and edges with four equivalent Cu(6)O6 octahedra. There are nine inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one O(1), one O(2), one O(3), one O(5), one O(7), and one O(8) atom to form CuO6 octahedra that share  a cornercorner with one Cu(2)O4 tetrahedra,  a cornercorner with one Cu(9)O4 tetrahedra, corners with two equivalent Mg(1)O4 tetrahedra, corners with two equivalent Cu(7)O4 tetrahedra,  an edgeedge with one Mg(2)O6 octahedra,  an edgeedge with one Cu(3)O6 octahedra, edges with two equivalent Mg(3)O6 octahedra, and edges with two equivalent Cu(1)O6 octahedra. In the second Cu site, Cu(2) is bonded to one O(2), one O(9), and two equivalent O(4) atoms to form CuO4 tetrahedra that share  a cornercorner with one Mg(3)O6 octahedra, corners with two equivalent Mg(5)O6 octahedra, corners with two equivalent Cu(1)O6 octahedra, corners with three equivalent Mg(2)O6 octahedra, and corners with four equivalent Cu(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 56-59°. In the third Cu site, Cu(3) is bonded to one O(16), one O(3), two equivalent O(1), and two equivalent O(17) atoms to form CuO6 octahedra that share corners with three equivalent Mg(1)O4 tetrahedra, corners with three equivalent Cu(9)O4 tetrahedra,  an edgeedge with one Mg(3)O6 octahedra,  an edgeedge with one Mg(6)O6 octahedra, edges with two equivalent Cu(1)O6 octahedra, and edges with two equivalent Cu(6)O6 octahedra. In the fourth Cu site, Cu(4) is bonded to one O(11), one O(12), one O(14), one O(4), one O(6), and one O(9) atom to form CuO6 octahedra that share  a cornercorner with one Cu(5)O4 tetrahedra,  a cornercorner with one Cu(7)O4 tetrahedra, corners with two equivalent Cu(2)O4 tetrahedra, corners with two equivalent Cu(8)O4 tetrahedra,  an edgeedge with one Mg(2)O6 octahedra,  an edgeedge with one Mg(4)O6 octahedra, edges with two equivalent Mg(5)O6 octahedra, and edges with two equivalent Cu(4)O6 octahedra. In the fifth Cu site, Cu(5) is bonded to one O(15), one O(6), and two equivalent O(10) atoms to form CuO4 tetrahedra that share  a cornercorner with one Mg(5)O6 octahedra, corners with two equivalent Mg(6)O6 octahedra, corners with two equivalent Cu(4)O6 octahedra, corners with three equivalent Mg(4)O6 octahedra, and corners with four equivalent Cu(6)O6 octahedra. The corner-sharing octahedral tilt angles range from 55-60°. In the sixth Cu site, Cu(6) is bonded to one O(10), one O(13), one O(15), one O(16), one O(17), and one O(18) atom to form CuO6 octahedra that share  a cornercorner with one Mg(1)O4 tetrahedra,  a cornercorner with one Cu(8)O4 tetrahedra, corners with two equivalent Cu(5)O4 tetrahedra, corners with two equivalent Cu(9)O4 tetrahedra,  an edgeedge with one Mg(4)O6 octahedra,  an edgeedge with one Cu(3)O6 octahedra, edges with two equivalent Mg(6)O6 octahedra, and edges with two equivalent Cu(6)O6 octahedra. In the seventh Cu site, Cu(7) is bonded to one O(14), one O(5), and two equivalent O(7) atoms to form CuO4 tetrahedra that share  a cornercorner with one Mg(5)O6 octahedra, corners with two equivalent Mg(3)O6 octahedra, corners with two equivalent Cu(4)O6 octahedra, corners with three equivalent Mg(2)O6 octahedra, and corners with four equivalent Cu(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 55-61°. In the eighth Cu site, Cu(8) is bonded to one O(11), one O(18), and two equivalent O(12) atoms to form CuO4 tetrahedra that share  a cornercorner with one Mg(6)O6 octahedra, corners with two equivalent Mg(5)O6 octahedra, corners with two equivalent Cu(6)O6 octahedra, corners with three equivalent Mg(4)O6 octahedra, and corners with four equivalent Cu(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 56-60°. In the ninth Cu site, Cu(9) is bonded to one O(16), one O(8), and two equivalent O(17) atoms to form CuO4 tetrahedra that share  a cornercorner with one Mg(3)O6 octahedra, corners with two equivalent Mg(6)O6 octahedra, corners with two equivalent Cu(1)O6 octahedra, corners with three equivalent Cu(3)O6 octahedra, and corners with four equivalent Cu(6)O6 octahedra. The corner-sharing octahedral tilt angles range from 55-62°. There are eighteen inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), one Mg(3), one Cu(1), and one Cu(3) atom to form distorted OMg2Cu2 trigonal pyramids that share  a cornercorner with one O(1)Mg2Cu2 trigonal pyramid,  a cornercorner with one O(13)Mg2Cu2 trigonal pyramid,  a cornercorner with one O(3)MgCu3 trigonal pyramid,  an edgeedge with one O(1)Mg2Cu2 trigonal pyramid, and  an edgeedge with one O(3)MgCu3 trigonal pyramid. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Mg(3), one Cu(2), and two equivalent Cu(1) atoms. In the third O site, O(3) is bonded to one Mg(1), one Cu(3), and two equivalent Cu(1) atoms to form a mixture of distorted corner and edge-sharing OMgCu3 trigonal pyramids. In the fourth O site, O(4) is bonded to one Mg(2), one Mg(5), one Cu(2), and one Cu(4) atom to form a mixture of distorted corner and edge-sharing OMg2Cu2 trigonal pyramids. In the fifth O site, O(5) is bonded in a rectangular see-saw-like geometry to one Mg(2), one Cu(7), and two equivalent Cu(1) atoms. In the sixth O site, O(6) is bonded in a rectangular see-saw-like geometry to one Mg(5), one Cu(5), and two equivalent Cu(4) atoms. In the seventh O site, O(7) is bonded in a rectangular see-saw-like geometry to one Mg(2), one Mg(3), one Cu(1), and one Cu(7) atom. In the eighth O site, O(8) is bonded in a rectangular see-saw-like geometry to one Mg(3), one Cu(9), and two equivalent Cu(1) atoms. In the ninth O site, O(9) is bonded in a rectangular see-saw-like geometry to one Mg(2), one Cu(2), and two equivalent Cu(4) atoms. In the tenth O site, O(10) is bonded in a rectangular see-saw-like geometry to one Mg(4), one Mg(6), one Cu(5), and one Cu(6) atom. In the eleventh O site, O(11) is bonded in a rectangular see-saw-like geometry to one Mg(4), one Cu(8), and two equivalent Cu(4) atoms. In the twelfth O site, O(12) is bonded to one Mg(4), one Mg(5), one Cu(4), and one Cu(8) atom to form a mixture of distorted corner and edge-sharing OMg2Cu2 trigonal pyramids. In the thirteenth O site, O(13) is bonded to one Mg(1), one Mg(6), and two equivalent Cu(6) atoms to form distorted OMg2Cu2 trigonal pyramids that share  a cornercorner with one O(3)MgCu3 trigonal pyramid and corners with two equivalent O(1)Mg2Cu2 trigonal pyramids. In the fourteenth O site, O(14) is bonded in a rectangular see-saw-like geometry to one Mg(5), one Cu(7), and two equivalent Cu(4) atoms. In the fifteenth O site, O(15) is bonded in a rectangular see-saw-like geometry to one Mg(4), one Cu(5), and two equivalent Cu(6) atoms. In the sixteenth O site, O(16) is bonded in a rectangular see-saw-like geometry to one Cu(3), one Cu(9), and two equivalent Cu(6) atoms. In the seventeenth O site, O(17) is bonded in a rectangular see-saw-like geometry to one Mg(6), one Cu(3), one Cu(6), and one Cu(9) atom. In the eighteenth O site, O(18) is bonded in a rectangular see-saw-like geometry to one Mg(6), one Cu(8), and two equivalent Cu(6) atoms. is represented by the CIF file [CIF]
data_Mg(CuO2)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.909
_cell_length_b   5.909
_cell_length_c   14.506
_cell_angle_alpha   89.737
_cell_angle_beta   89.737
_cell_angle_gamma   60.559
_symmetry_Int_Tables_number   1
_cell_volume   441.120
_cell_formula_units_Z   6
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  0.656  0.656  0.041  1.0
  Mg  Mg1  1  0.333  0.333  0.333  1.0
  Mg  Mg2  1  0.165  0.165  0.167  1.0
  Mg  Mg3  1  0.667  0.667  0.666  1.0
  Mg  Mg4  1  0.500  0.500  0.500  1.0
  Mg  Mg5  1  0.835  0.835  0.833  1.0
  Cu  Cu6  1  0.165  0.668  0.168  1.0
  Cu  Cu7  1  0.993  0.993  0.380  1.0
  Cu  Cu8  1  0.000  0.000  0.001  1.0
  Cu  Cu9  1  0.668  0.165  0.168  1.0
  Cu  Cu10  1  0.500  0.000  0.500  1.0
  Cu  Cu11  1  0.326  0.326  0.708  1.0
  Cu  Cu12  1  0.000  0.500  0.500  1.0
  Cu  Cu13  1  0.833  0.335  0.832  1.0
  Cu  Cu14  1  0.673  0.673  0.291  1.0
  Cu  Cu15  1  0.335  0.833  0.832  1.0
  Cu  Cu16  1  0.007  0.007  0.621  1.0
  Cu  Cu17  1  0.337  0.337  0.958  1.0
  O  O18  1  0.293  0.842  0.086  1.0
  O  O19  1  0.995  0.995  0.246  1.0
  O  O20  1  0.842  0.293  0.086  1.0
  O  O21  1  0.843  0.843  0.088  1.0
  O  O22  1  0.639  0.169  0.423  1.0
  O  O23  1  0.498  0.498  0.243  1.0
  O  O24  1  0.328  0.328  0.577  1.0
  O  O25  1  0.500  0.024  0.243  1.0
  O  O26  1  0.169  0.639  0.423  1.0
  O  O27  1  0.341  0.341  0.092  1.0
  O  O28  1  0.172  0.172  0.422  1.0
  O  O29  1  0.024  0.500  0.243  1.0
  O  O30  1  0.979  0.501  0.756  1.0
  O  O31  1  0.828  0.828  0.578  1.0
  O  O32  1  0.833  0.360  0.577  1.0
  O  O33  1  0.501  0.979  0.756  1.0
  O  O34  1  0.659  0.659  0.903  1.0
  O  O35  1  0.673  0.673  0.423  1.0
  O  O36  1  0.501  0.501  0.753  1.0
  O  O37  1  0.360  0.833  0.577  1.0
  O  O38  1  0.161  0.161  0.917  1.0
  O  O39  1  0.162  0.703  0.917  1.0
  O  O40  1  0.009  0.009  0.758  1.0
  O  O41  1  0.703  0.162  0.917  1.0
[/CIF]
.
The material described by MgCu2O4 is Spinel-like structured and crystallizes in the monoclinic Cm space group. There are six inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to one O(13), one O(3), and two equivalent O(1) atoms to form MgO4 tetrahedra that share  a cornercorner with one Mg(6)O6 octahedra, corners with two equivalent Mg(3)O6 octahedra, corners with two equivalent Cu(6)O6 octahedra, corners with three equivalent Cu(3)O6 octahedra, and corners with four equivalent Cu(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 57-60°. In the second Mg site, Mg(2) is bonded to one O(5), one O(9), two equivalent O(4), and two equivalent O(7) atoms to form MgO6 octahedra that share corners with three equivalent Cu(2)O4 tetrahedra, corners with three equivalent Cu(7)O4 tetrahedra,  an edgeedge with one Mg(3)O6 octahedra,  an edgeedge with one Mg(5)O6 octahedra, edges with two equivalent Cu(1)O6 octahedra, and edges with two equivalent Cu(4)O6 octahedra. In the third Mg site, Mg(3) is bonded to one O(2), one O(8), two equivalent O(1), and two equivalent O(7) atoms to form MgO6 octahedra that share  a cornercorner with one Cu(2)O4 tetrahedra,  a cornercorner with one Cu(9)O4 tetrahedra, corners with two equivalent Mg(1)O4 tetrahedra, corners with two equivalent Cu(7)O4 tetrahedra,  an edgeedge with one Mg(2)O6 octahedra,  an edgeedge with one Cu(3)O6 octahedra, and edges with four equivalent Cu(1)O6 octahedra. In the fourth Mg site, Mg(4) is bonded to one O(11), one O(15), two equivalent O(10), and two equivalent O(12) atoms to form MgO6 octahedra that share corners with three equivalent Cu(5)O4 tetrahedra, corners with three equivalent Cu(8)O4 tetrahedra,  an edgeedge with one Mg(5)O6 octahedra,  an edgeedge with one Mg(6)O6 octahedra, edges with two equivalent Cu(4)O6 octahedra, and edges with two equivalent Cu(6)O6 octahedra. In the fifth Mg site, Mg(5) is bonded to one O(14), one O(6), two equivalent O(12), and two equivalent O(4) atoms to form MgO6 octahedra that share  a cornercorner with one Cu(5)O4 tetrahedra,  a cornercorner with one Cu(7)O4 tetrahedra, corners with two equivalent Cu(2)O4 tetrahedra, corners with two equivalent Cu(8)O4 tetrahedra,  an edgeedge with one Mg(2)O6 octahedra,  an edgeedge with one Mg(4)O6 octahedra, and edges with four equivalent Cu(4)O6 octahedra. In the sixth Mg site, Mg(6) is bonded to one O(13), one O(18), two equivalent O(10), and two equivalent O(17) atoms to form MgO6 octahedra that share  a cornercorner with one Mg(1)O4 tetrahedra,  a cornercorner with one Cu(8)O4 tetrahedra, corners with two equivalent Cu(5)O4 tetrahedra, corners with two equivalent Cu(9)O4 tetrahedra,  an edgeedge with one Mg(4)O6 octahedra,  an edgeedge with one Cu(3)O6 octahedra, and edges with four equivalent Cu(6)O6 octahedra. There are nine inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one O(1), one O(2), one O(3), one O(5), one O(7), and one O(8) atom to form CuO6 octahedra that share  a cornercorner with one Cu(2)O4 tetrahedra,  a cornercorner with one Cu(9)O4 tetrahedra, corners with two equivalent Mg(1)O4 tetrahedra, corners with two equivalent Cu(7)O4 tetrahedra,  an edgeedge with one Mg(2)O6 octahedra,  an edgeedge with one Cu(3)O6 octahedra, edges with two equivalent Mg(3)O6 octahedra, and edges with two equivalent Cu(1)O6 octahedra. In the second Cu site, Cu(2) is bonded to one O(2), one O(9), and two equivalent O(4) atoms to form CuO4 tetrahedra that share  a cornercorner with one Mg(3)O6 octahedra, corners with two equivalent Mg(5)O6 octahedra, corners with two equivalent Cu(1)O6 octahedra, corners with three equivalent Mg(2)O6 octahedra, and corners with four equivalent Cu(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 56-59°. In the third Cu site, Cu(3) is bonded to one O(16), one O(3), two equivalent O(1), and two equivalent O(17) atoms to form CuO6 octahedra that share corners with three equivalent Mg(1)O4 tetrahedra, corners with three equivalent Cu(9)O4 tetrahedra,  an edgeedge with one Mg(3)O6 octahedra,  an edgeedge with one Mg(6)O6 octahedra, edges with two equivalent Cu(1)O6 octahedra, and edges with two equivalent Cu(6)O6 octahedra. In the fourth Cu site, Cu(4) is bonded to one O(11), one O(12), one O(14), one O(4), one O(6), and one O(9) atom to form CuO6 octahedra that share  a cornercorner with one Cu(5)O4 tetrahedra,  a cornercorner with one Cu(7)O4 tetrahedra, corners with two equivalent Cu(2)O4 tetrahedra, corners with two equivalent Cu(8)O4 tetrahedra,  an edgeedge with one Mg(2)O6 octahedra,  an edgeedge with one Mg(4)O6 octahedra, edges with two equivalent Mg(5)O6 octahedra, and edges with two equivalent Cu(4)O6 octahedra. In the fifth Cu site, Cu(5) is bonded to one O(15), one O(6), and two equivalent O(10) atoms to form CuO4 tetrahedra that share  a cornercorner with one Mg(5)O6 octahedra, corners with two equivalent Mg(6)O6 octahedra, corners with two equivalent Cu(4)O6 octahedra, corners with three equivalent Mg(4)O6 octahedra, and corners with four equivalent Cu(6)O6 octahedra. The corner-sharing octahedral tilt angles range from 55-60°. In the sixth Cu site, Cu(6) is bonded to one O(10), one O(13), one O(15), one O(16), one O(17), and one O(18) atom to form CuO6 octahedra that share  a cornercorner with one Mg(1)O4 tetrahedra,  a cornercorner with one Cu(8)O4 tetrahedra, corners with two equivalent Cu(5)O4 tetrahedra, corners with two equivalent Cu(9)O4 tetrahedra,  an edgeedge with one Mg(4)O6 octahedra,  an edgeedge with one Cu(3)O6 octahedra, edges with two equivalent Mg(6)O6 octahedra, and edges with two equivalent Cu(6)O6 octahedra. In the seventh Cu site, Cu(7) is bonded to one O(14), one O(5), and two equivalent O(7) atoms to form CuO4 tetrahedra that share  a cornercorner with one Mg(5)O6 octahedra, corners with two equivalent Mg(3)O6 octahedra, corners with two equivalent Cu(4)O6 octahedra, corners with three equivalent Mg(2)O6 octahedra, and corners with four equivalent Cu(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 55-61°. In the eighth Cu site, Cu(8) is bonded to one O(11), one O(18), and two equivalent O(12) atoms to form CuO4 tetrahedra that share  a cornercorner with one Mg(6)O6 octahedra, corners with two equivalent Mg(5)O6 octahedra, corners with two equivalent Cu(6)O6 octahedra, corners with three equivalent Mg(4)O6 octahedra, and corners with four equivalent Cu(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 56-60°. In the ninth Cu site, Cu(9) is bonded to one O(16), one O(8), and two equivalent O(17) atoms to form CuO4 tetrahedra that share  a cornercorner with one Mg(3)O6 octahedra, corners with two equivalent Mg(6)O6 octahedra, corners with two equivalent Cu(1)O6 octahedra, corners with three equivalent Cu(3)O6 octahedra, and corners with four equivalent Cu(6)O6 octahedra. The corner-sharing octahedral tilt angles range from 55-62°. There are eighteen inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), one Mg(3), one Cu(1), and one Cu(3) atom to form distorted OMg2Cu2 trigonal pyramids that share  a cornercorner with one O(1)Mg2Cu2 trigonal pyramid,  a cornercorner with one O(13)Mg2Cu2 trigonal pyramid,  a cornercorner with one O(3)MgCu3 trigonal pyramid,  an edgeedge with one O(1)Mg2Cu2 trigonal pyramid, and  an edgeedge with one O(3)MgCu3 trigonal pyramid. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Mg(3), one Cu(2), and two equivalent Cu(1) atoms. In the third O site, O(3) is bonded to one Mg(1), one Cu(3), and two equivalent Cu(1) atoms to form a mixture of distorted corner and edge-sharing OMgCu3 trigonal pyramids. In the fourth O site, O(4) is bonded to one Mg(2), one Mg(5), one Cu(2), and one Cu(4) atom to form a mixture of distorted corner and edge-sharing OMg2Cu2 trigonal pyramids. In the fifth O site, O(5) is bonded in a rectangular see-saw-like geometry to one Mg(2), one Cu(7), and two equivalent Cu(1) atoms. In the sixth O site, O(6) is bonded in a rectangular see-saw-like geometry to one Mg(5), one Cu(5), and two equivalent Cu(4) atoms. In the seventh O site, O(7) is bonded in a rectangular see-saw-like geometry to one Mg(2), one Mg(3), one Cu(1), and one Cu(7) atom. In the eighth O site, O(8) is bonded in a rectangular see-saw-like geometry to one Mg(3), one Cu(9), and two equivalent Cu(1) atoms. In the ninth O site, O(9) is bonded in a rectangular see-saw-like geometry to one Mg(2), one Cu(2), and two equivalent Cu(4) atoms. In the tenth O site, O(10) is bonded in a rectangular see-saw-like geometry to one Mg(4), one Mg(6), one Cu(5), and one Cu(6) atom. In the eleventh O site, O(11) is bonded in a rectangular see-saw-like geometry to one Mg(4), one Cu(8), and two equivalent Cu(4) atoms. In the twelfth O site, O(12) is bonded to one Mg(4), one Mg(5), one Cu(4), and one Cu(8) atom to form a mixture of distorted corner and edge-sharing OMg2Cu2 trigonal pyramids. In the thirteenth O site, O(13) is bonded to one Mg(1), one Mg(6), and two equivalent Cu(6) atoms to form distorted OMg2Cu2 trigonal pyramids that share  a cornercorner with one O(3)MgCu3 trigonal pyramid and corners with two equivalent O(1)Mg2Cu2 trigonal pyramids. In the fourteenth O site, O(14) is bonded in a rectangular see-saw-like geometry to one Mg(5), one Cu(7), and two equivalent Cu(4) atoms. In the fifteenth O site, O(15) is bonded in a rectangular see-saw-like geometry to one Mg(4), one Cu(5), and two equivalent Cu(6) atoms. In the sixteenth O site, O(16) is bonded in a rectangular see-saw-like geometry to one Cu(3), one Cu(9), and two equivalent Cu(6) atoms. In the seventeenth O site, O(17) is bonded in a rectangular see-saw-like geometry to one Mg(6), one Cu(3), one Cu(6), and one Cu(9) atom. In the eighteenth O site, O(18) is bonded in a rectangular see-saw-like geometry to one Mg(6), one Cu(8), and two equivalent Cu(6) atoms. is represented by the CIF file [CIF]
data_Mg(CuO2)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.909
_cell_length_b   5.909
_cell_length_c   14.506
_cell_angle_alpha   89.737
_cell_angle_beta   89.737
_cell_angle_gamma   60.559
_symmetry_Int_Tables_number   1
_cell_volume   441.120
_cell_formula_units_Z   6
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  0.656  0.656  0.041  1.0
  Mg  Mg1  1  0.333  0.333  0.333  1.0
  Mg  Mg2  1  0.165  0.165  0.167  1.0
  Mg  Mg3  1  0.667  0.667  0.666  1.0
  Mg  Mg4  1  0.500  0.500  0.500  1.0
  Mg  Mg5  1  0.835  0.835  0.833  1.0
  Cu  Cu6  1  0.165  0.668  0.168  1.0
  Cu  Cu7  1  0.993  0.993  0.380  1.0
  Cu  Cu8  1  0.000  0.000  0.001  1.0
  Cu  Cu9  1  0.668  0.165  0.168  1.0
  Cu  Cu10  1  0.500  0.000  0.500  1.0
  Cu  Cu11  1  0.326  0.326  0.708  1.0
  Cu  Cu12  1  0.000  0.500  0.500  1.0
  Cu  Cu13  1  0.833  0.335  0.832  1.0
  Cu  Cu14  1  0.673  0.673  0.291  1.0
  Cu  Cu15  1  0.335  0.833  0.832  1.0
  Cu  Cu16  1  0.007  0.007  0.621  1.0
  Cu  Cu17  1  0.337  0.337  0.958  1.0
  O  O18  1  0.293  0.842  0.086  1.0
  O  O19  1  0.995  0.995  0.246  1.0
  O  O20  1  0.842  0.293  0.086  1.0
  O  O21  1  0.843  0.843  0.088  1.0
  O  O22  1  0.639  0.169  0.423  1.0
  O  O23  1  0.498  0.498  0.243  1.0
  O  O24  1  0.328  0.328  0.577  1.0
  O  O25  1  0.500  0.024  0.243  1.0
  O  O26  1  0.169  0.639  0.423  1.0
  O  O27  1  0.341  0.341  0.092  1.0
  O  O28  1  0.172  0.172  0.422  1.0
  O  O29  1  0.024  0.500  0.243  1.0
  O  O30  1  0.979  0.501  0.756  1.0
  O  O31  1  0.828  0.828  0.578  1.0
  O  O32  1  0.833  0.360  0.577  1.0
  O  O33  1  0.501  0.979  0.756  1.0
  O  O34  1  0.659  0.659  0.903  1.0
  O  O35  1  0.673  0.673  0.423  1.0
  O  O36  1  0.501  0.501  0.753  1.0
  O  O37  1  0.360  0.833  0.577  1.0
  O  O38  1  0.161  0.161  0.917  1.0
  O  O39  1  0.162  0.703  0.917  1.0
  O  O40  1  0.009  0.009  0.758  1.0
  O  O41  1  0.703  0.162  0.917  1.0
[/CIF]
.