The structure described by MgCu2(SbO4)2 crystallizes in the monoclinic P2_1/c space group. Mg(1) is bonded to one O(1), one O(4), one O(7), one O(8), and two equivalent O(3) atoms to form distorted MgO6 octahedra that share corners with three equivalent Sb(1)O4 tetrahedra, corners with three equivalent Sb(2)O4 tetrahedra,  an edgeedge with one Mg(1)O6 octahedra, and edges with two equivalent Cu(1)O5 trigonal bipyramids. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one O(1), one O(3), one O(5), one O(6), and one O(7) atom to form CuO5 trigonal bipyramids that share corners with two equivalent Sb(1)O4 tetrahedra, corners with three equivalent Sb(2)O4 tetrahedra, and edges with two equivalent Mg(1)O6 octahedra. In the second Cu site, Cu(2) is bonded in a distorted rectangular see-saw-like geometry to one O(2), one O(4), one O(6), and one O(8) atom. There are two inequivalent Sb sites. In the first Sb site, Sb(1) is bonded to one O(1), one O(2), one O(4), and one O(7) atom to form SbO4 tetrahedra that share corners with three equivalent Mg(1)O6 octahedra and corners with two equivalent Cu(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 36-52°. In the second Sb site, Sb(2) is bonded to one O(3), one O(5), one O(6), and one O(8) atom to form SbO4 tetrahedra that share corners with three equivalent Mg(1)O6 octahedra and corners with three equivalent Cu(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 57-61°. There are eight inequivalent O sites. In the first O site, O(7) is bonded in a distorted trigonal planar geometry to one Mg(1), one Cu(1), and one Sb(1) atom. In the second O site, O(8) is bonded in a trigonal planar geometry to one Mg(1), one Cu(2), and one Sb(2) atom. In the third O site, O(1) is bonded in a trigonal planar geometry to one Mg(1), one Cu(1), and one Sb(1) atom. In the fourth O site, O(2) is bonded in a distorted bent 150 degrees geometry to one Cu(2) and one Sb(1) atom. In the fifth O site, O(3) is bonded to two equivalent Mg(1), one Cu(1), and one Sb(2) atom to form distorted edge-sharing OMg2CuSb trigonal pyramids. In the sixth O site, O(4) is bonded in a distorted trigonal planar geometry to one Mg(1), one Cu(2), and one Sb(1) atom. In the seventh O site, O(5) is bonded in a bent 120 degrees geometry to one Cu(1) and one Sb(2) atom. In the eighth O site, O(6) is bonded in a distorted trigonal planar geometry to one Cu(1), one Cu(2), and one Sb(2) atom. is represented by the CIF file [CIF]
data_MgCu2(SbO4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.713
_cell_length_b   6.583
_cell_length_c   12.305
_cell_angle_alpha   88.190
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   705.418
_cell_formula_units_Z   4
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  0.834  0.892  0.051  1.0
  Mg  Mg1  1  0.166  0.108  0.949  1.0
  Mg  Mg2  1  0.334  0.108  0.449  1.0
  Mg  Mg3  1  0.666  0.892  0.551  1.0
  Cu  Cu4  1  0.821  0.240  0.871  1.0
  Cu  Cu5  1  0.941  0.621  0.624  1.0
  Cu  Cu6  1  0.059  0.379  0.376  1.0
  Cu  Cu7  1  0.179  0.760  0.129  1.0
  Cu  Cu8  1  0.679  0.240  0.371  1.0
  Cu  Cu9  1  0.559  0.621  0.124  1.0
  Cu  Cu10  1  0.321  0.760  0.629  1.0
  Cu  Cu11  1  0.441  0.379  0.876  1.0
  Sb  Sb12  1  0.547  0.903  0.843  1.0
  Sb  Sb13  1  0.953  0.903  0.343  1.0
  Sb  Sb14  1  0.914  0.392  0.135  1.0
  Sb  Sb15  1  0.047  0.097  0.657  1.0
  Sb  Sb16  1  0.086  0.608  0.865  1.0
  Sb  Sb17  1  0.414  0.608  0.365  1.0
  Sb  Sb18  1  0.586  0.392  0.635  1.0
  Sb  Sb19  1  0.453  0.097  0.157  1.0
  O  O20  1  0.754  0.967  0.398  1.0
  O  O21  1  0.978  0.345  0.590  1.0
  O  O22  1  0.425  0.813  0.475  1.0
  O  O23  1  0.925  0.187  0.025  1.0
  O  O24  1  0.746  0.967  0.898  1.0
  O  O25  1  0.246  0.033  0.602  1.0
  O  O26  1  0.892  0.909  0.612  1.0
  O  O27  1  0.119  0.485  0.148  1.0
  O  O28  1  0.381  0.485  0.648  1.0
  O  O29  1  0.126  0.703  0.715  1.0
  O  O30  1  0.626  0.297  0.785  1.0
  O  O31  1  0.881  0.515  0.852  1.0
  O  O32  1  0.108  0.091  0.388  1.0
  O  O33  1  0.461  0.123  0.310  1.0
  O  O34  1  0.725  0.593  0.580  1.0
  O  O35  1  0.775  0.593  0.080  1.0
  O  O36  1  0.961  0.877  0.190  1.0
  O  O37  1  0.619  0.515  0.352  1.0
  O  O38  1  0.539  0.877  0.690  1.0
  O  O39  1  0.575  0.187  0.525  1.0
  O  O40  1  0.522  0.345  0.090  1.0
  O  O41  1  0.874  0.297  0.285  1.0
  O  O42  1  0.254  0.033  0.102  1.0
  O  O43  1  0.608  0.909  0.112  1.0
  O  O44  1  0.075  0.813  0.975  1.0
  O  O45  1  0.225  0.407  0.920  1.0
  O  O46  1  0.022  0.655  0.410  1.0
  O  O47  1  0.478  0.655  0.910  1.0
  O  O48  1  0.392  0.091  0.888  1.0
  O  O49  1  0.275  0.407  0.420  1.0
  O  O50  1  0.374  0.703  0.215  1.0
  O  O51  1  0.039  0.123  0.810  1.0
[/CIF]
.
The structure described by MgCu2(SbO4)2 crystallizes in the monoclinic P2_1/c space group. Mg(1) is bonded to one O(1), one O(4), one O(7), one O(8), and two equivalent O(3) atoms to form distorted MgO6 octahedra that share corners with three equivalent Sb(1)O4 tetrahedra, corners with three equivalent Sb(2)O4 tetrahedra,  an edgeedge with one Mg(1)O6 octahedra, and edges with two equivalent Cu(1)O5 trigonal bipyramids. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one O(1), one O(3), one O(5), one O(6), and one O(7) atom to form CuO5 trigonal bipyramids that share corners with two equivalent Sb(1)O4 tetrahedra, corners with three equivalent Sb(2)O4 tetrahedra, and edges with two equivalent Mg(1)O6 octahedra. In the second Cu site, Cu(2) is bonded in a distorted rectangular see-saw-like geometry to one O(2), one O(4), one O(6), and one O(8) atom. There are two inequivalent Sb sites. In the first Sb site, Sb(1) is bonded to one O(1), one O(2), one O(4), and one O(7) atom to form SbO4 tetrahedra that share corners with three equivalent Mg(1)O6 octahedra and corners with two equivalent Cu(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 36-52°. In the second Sb site, Sb(2) is bonded to one O(3), one O(5), one O(6), and one O(8) atom to form SbO4 tetrahedra that share corners with three equivalent Mg(1)O6 octahedra and corners with three equivalent Cu(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 57-61°. There are eight inequivalent O sites. In the first O site, O(7) is bonded in a distorted trigonal planar geometry to one Mg(1), one Cu(1), and one Sb(1) atom. In the second O site, O(8) is bonded in a trigonal planar geometry to one Mg(1), one Cu(2), and one Sb(2) atom. In the third O site, O(1) is bonded in a trigonal planar geometry to one Mg(1), one Cu(1), and one Sb(1) atom. In the fourth O site, O(2) is bonded in a distorted bent 150 degrees geometry to one Cu(2) and one Sb(1) atom. In the fifth O site, O(3) is bonded to two equivalent Mg(1), one Cu(1), and one Sb(2) atom to form distorted edge-sharing OMg2CuSb trigonal pyramids. In the sixth O site, O(4) is bonded in a distorted trigonal planar geometry to one Mg(1), one Cu(2), and one Sb(1) atom. In the seventh O site, O(5) is bonded in a bent 120 degrees geometry to one Cu(1) and one Sb(2) atom. In the eighth O site, O(6) is bonded in a distorted trigonal planar geometry to one Cu(1), one Cu(2), and one Sb(2) atom. is represented by the CIF file [CIF]
data_MgCu2(SbO4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.713
_cell_length_b   6.583
_cell_length_c   12.305
_cell_angle_alpha   88.190
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   705.418
_cell_formula_units_Z   4
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  0.834  0.892  0.051  1.0
  Mg  Mg1  1  0.166  0.108  0.949  1.0
  Mg  Mg2  1  0.334  0.108  0.449  1.0
  Mg  Mg3  1  0.666  0.892  0.551  1.0
  Cu  Cu4  1  0.821  0.240  0.871  1.0
  Cu  Cu5  1  0.941  0.621  0.624  1.0
  Cu  Cu6  1  0.059  0.379  0.376  1.0
  Cu  Cu7  1  0.179  0.760  0.129  1.0
  Cu  Cu8  1  0.679  0.240  0.371  1.0
  Cu  Cu9  1  0.559  0.621  0.124  1.0
  Cu  Cu10  1  0.321  0.760  0.629  1.0
  Cu  Cu11  1  0.441  0.379  0.876  1.0
  Sb  Sb12  1  0.547  0.903  0.843  1.0
  Sb  Sb13  1  0.953  0.903  0.343  1.0
  Sb  Sb14  1  0.914  0.392  0.135  1.0
  Sb  Sb15  1  0.047  0.097  0.657  1.0
  Sb  Sb16  1  0.086  0.608  0.865  1.0
  Sb  Sb17  1  0.414  0.608  0.365  1.0
  Sb  Sb18  1  0.586  0.392  0.635  1.0
  Sb  Sb19  1  0.453  0.097  0.157  1.0
  O  O20  1  0.754  0.967  0.398  1.0
  O  O21  1  0.978  0.345  0.590  1.0
  O  O22  1  0.425  0.813  0.475  1.0
  O  O23  1  0.925  0.187  0.025  1.0
  O  O24  1  0.746  0.967  0.898  1.0
  O  O25  1  0.246  0.033  0.602  1.0
  O  O26  1  0.892  0.909  0.612  1.0
  O  O27  1  0.119  0.485  0.148  1.0
  O  O28  1  0.381  0.485  0.648  1.0
  O  O29  1  0.126  0.703  0.715  1.0
  O  O30  1  0.626  0.297  0.785  1.0
  O  O31  1  0.881  0.515  0.852  1.0
  O  O32  1  0.108  0.091  0.388  1.0
  O  O33  1  0.461  0.123  0.310  1.0
  O  O34  1  0.725  0.593  0.580  1.0
  O  O35  1  0.775  0.593  0.080  1.0
  O  O36  1  0.961  0.877  0.190  1.0
  O  O37  1  0.619  0.515  0.352  1.0
  O  O38  1  0.539  0.877  0.690  1.0
  O  O39  1  0.575  0.187  0.525  1.0
  O  O40  1  0.522  0.345  0.090  1.0
  O  O41  1  0.874  0.297  0.285  1.0
  O  O42  1  0.254  0.033  0.102  1.0
  O  O43  1  0.608  0.909  0.112  1.0
  O  O44  1  0.075  0.813  0.975  1.0
  O  O45  1  0.225  0.407  0.920  1.0
  O  O46  1  0.022  0.655  0.410  1.0
  O  O47  1  0.478  0.655  0.910  1.0
  O  O48  1  0.392  0.091  0.888  1.0
  O  O49  1  0.275  0.407  0.420  1.0
  O  O50  1  0.374  0.703  0.215  1.0
  O  O51  1  0.039  0.123  0.810  1.0
[/CIF]
.