The material described by MgCu2(SeO4)2 crystallizes in the orthorhombic Amm2 space group. Mg(1) is bonded to two equivalent O(1) and two equivalent O(3) atoms to form distorted MgO4 tetrahedra that share corners with six equivalent Cu(1)O6 octahedra, corners with two equivalent Se(1)O4 tetrahedra, and  an edgeedge with one Se(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 67-69°. Cu(1) is bonded to one O(1), one O(2), two equivalent O(3), and two equivalent O(4) atoms to form distorted CuO6 octahedra that share corners with three equivalent Mg(1)O4 tetrahedra, corners with three equivalent Se(1)O4 tetrahedra, corners with three equivalent Se(2)O4 tetrahedra, and edges with two equivalent Cu(1)O6 octahedra. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded to two equivalent O(1) and two equivalent O(4) atoms to form SeO4 tetrahedra that share corners with six equivalent Cu(1)O6 octahedra and corners with two equivalent Mg(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 44-53°. In the second Se site, Se(2) is bonded to two equivalent O(2) and two equivalent O(3) atoms to form SeO4 tetrahedra that share corners with six equivalent Cu(1)O6 octahedra and  an edgeedge with one Mg(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 42-55°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Mg(1), one Cu(1), and one Se(1) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Cu(1) and one Se(2) atom. In the third O site, O(3) is bonded in a distorted L-shaped geometry to one Mg(1), two equivalent Cu(1), and one Se(2) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to two equivalent Cu(1) and one Se(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_MgCu2(SeO4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.242
_cell_length_b   5.242
_cell_length_c   6.495
_cell_angle_alpha   89.989
_cell_angle_beta   90.011
_cell_angle_gamma   107.392
_symmetry_Int_Tables_number   1
_cell_volume   170.329
_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
  Mg  Mg0  1  0.675  0.325  0.750  1.0
  Cu  Cu1  1  0.005  0.995  0.037  1.0
  Cu  Cu2  1  0.005  0.995  0.463  1.0
  Se  Se3  1  0.637  0.363  0.250  1.0
  Se  Se4  1  0.345  0.655  0.750  1.0
  O  O5  1  0.767  0.233  0.466  1.0
  O  O6  1  0.234  0.766  0.537  1.0
  O  O7  1  0.268  0.309  0.750  1.0
  O  O8  1  0.781  0.707  0.250  1.0
  O  O9  1  0.767  0.233  0.034  1.0
  O  O10  1  0.234  0.766  0.963  1.0
  O  O11  1  0.691  0.732  0.750  1.0
  O  O12  1  0.293  0.219  0.250  1.0
[/CIF]
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The material described by MgCu2(SeO4)2 crystallizes in the orthorhombic Amm2 space group. Mg(1) is bonded to two equivalent O(1) and two equivalent O(3) atoms to form distorted MgO4 tetrahedra that share corners with six equivalent Cu(1)O6 octahedra, corners with two equivalent Se(1)O4 tetrahedra, and  an edgeedge with one Se(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 67-69°. Cu(1) is bonded to one O(1), one O(2), two equivalent O(3), and two equivalent O(4) atoms to form distorted CuO6 octahedra that share corners with three equivalent Mg(1)O4 tetrahedra, corners with three equivalent Se(1)O4 tetrahedra, corners with three equivalent Se(2)O4 tetrahedra, and edges with two equivalent Cu(1)O6 octahedra. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded to two equivalent O(1) and two equivalent O(4) atoms to form SeO4 tetrahedra that share corners with six equivalent Cu(1)O6 octahedra and corners with two equivalent Mg(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 44-53°. In the second Se site, Se(2) is bonded to two equivalent O(2) and two equivalent O(3) atoms to form SeO4 tetrahedra that share corners with six equivalent Cu(1)O6 octahedra and  an edgeedge with one Mg(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 42-55°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Mg(1), one Cu(1), and one Se(1) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Cu(1) and one Se(2) atom. In the third O site, O(3) is bonded in a distorted L-shaped geometry to one Mg(1), two equivalent Cu(1), and one Se(2) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to two equivalent Cu(1) and one Se(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_MgCu2(SeO4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.242
_cell_length_b   5.242
_cell_length_c   6.495
_cell_angle_alpha   89.989
_cell_angle_beta   90.011
_cell_angle_gamma   107.392
_symmetry_Int_Tables_number   1
_cell_volume   170.329
_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
  Mg  Mg0  1  0.675  0.325  0.750  1.0
  Cu  Cu1  1  0.005  0.995  0.037  1.0
  Cu  Cu2  1  0.005  0.995  0.463  1.0
  Se  Se3  1  0.637  0.363  0.250  1.0
  Se  Se4  1  0.345  0.655  0.750  1.0
  O  O5  1  0.767  0.233  0.466  1.0
  O  O6  1  0.234  0.766  0.537  1.0
  O  O7  1  0.268  0.309  0.750  1.0
  O  O8  1  0.781  0.707  0.250  1.0
  O  O9  1  0.767  0.233  0.034  1.0
  O  O10  1  0.234  0.766  0.963  1.0
  O  O11  1  0.691  0.732  0.750  1.0
  O  O12  1  0.293  0.219  0.250  1.0
[/CIF]
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