The material structure described by MgCu2Tl(SeO5)2 crystallizes in the monoclinic Cm space group. Mg(1) is bonded to one O(3), one O(7), one O(8), and two equivalent O(6) atoms to form MgO5 trigonal bipyramids that share  a cornercorner with one Se(1)O4 tetrahedra and corners with two equivalent Se(2)O4 tetrahedra. Cu(1) is bonded in a distorted rectangular see-saw-like geometry to one O(5), one O(6), one O(7), and one O(8) atom. Tl(1) is bonded in a 4-coordinate geometry to one O(1), one O(2), and two equivalent O(5) atoms. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded to one O(1), one O(3), and two equivalent O(5) atoms to form SeO4 tetrahedra that share  a cornercorner with one Mg(1)O5 trigonal bipyramid. In the second Se site, Se(2) is bonded to one O(2), one O(4), and two equivalent O(6) atoms to form SeO4 tetrahedra that share corners with two equivalent Mg(1)O5 trigonal bipyramids. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to one Tl(1) and one Se(1) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to one Tl(1) and one Se(2) atom. In the third O site, O(3) is bonded in a linear geometry to one Mg(1) and one Se(1) atom. In the fourth O site, O(4) is bonded in a single-bond geometry to one Se(2) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Cu(1), one Tl(1), and one Se(1) atom. In the sixth O site, O(6) is bonded in a trigonal planar geometry to one Mg(1), one Cu(1), and one Se(2) atom. In the seventh O site, O(7) is bonded in a trigonal non-coplanar geometry to one Mg(1) and two equivalent Cu(1) atoms. In the eighth O site, O(8) is bonded in a trigonal planar geometry to one Mg(1) and two equivalent Cu(1) atoms. is represented by the CIF card [CIF]
data_MgTlCu2(SeO5)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.074
_cell_length_b   6.074
_cell_length_c   8.719
_cell_angle_alpha   60.477
_cell_angle_beta   119.522
_cell_angle_gamma   116.303
_symmetry_Int_Tables_number   1
_cell_volume   234.882
_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  0.563  0.437  0.162  1.0
  Tl  Tl1  1  0.506  0.494  0.536  1.0
  Cu  Cu2  1  1.000  0.500  0.007  1.0
  Cu  Cu3  1  0.500  0.000  0.007  1.0
  Se  Se4  1  0.918  0.082  0.712  1.0
  Se  Se5  1  0.095  0.905  0.296  1.0
  O  O6  1  0.824  0.176  0.816  1.0
  O  O7  1  0.193  0.806  0.197  1.0
  O  O8  1  0.793  0.207  0.478  1.0
  O  O9  1  0.206  0.794  0.526  1.0
  O  O10  1  0.253  0.184  0.780  1.0
  O  O11  1  0.816  0.747  0.780  1.0
  O  O12  1  0.756  0.795  0.216  1.0
  O  O13  1  0.205  0.244  0.216  1.0
  O  O14  1  0.321  0.679  0.975  1.0
  O  O15  1  0.696  0.304  0.069  1.0
[/CIF]
.
The material structure described by MgCu2Tl(SeO5)2 crystallizes in the monoclinic Cm space group. Mg(1) is bonded to one O(3), one O(7), one O(8), and two equivalent O(6) atoms to form MgO5 trigonal bipyramids that share  a cornercorner with one Se(1)O4 tetrahedra and corners with two equivalent Se(2)O4 tetrahedra. Cu(1) is bonded in a distorted rectangular see-saw-like geometry to one O(5), one O(6), one O(7), and one O(8) atom. Tl(1) is bonded in a 4-coordinate geometry to one O(1), one O(2), and two equivalent O(5) atoms. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded to one O(1), one O(3), and two equivalent O(5) atoms to form SeO4 tetrahedra that share  a cornercorner with one Mg(1)O5 trigonal bipyramid. In the second Se site, Se(2) is bonded to one O(2), one O(4), and two equivalent O(6) atoms to form SeO4 tetrahedra that share corners with two equivalent Mg(1)O5 trigonal bipyramids. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to one Tl(1) and one Se(1) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to one Tl(1) and one Se(2) atom. In the third O site, O(3) is bonded in a linear geometry to one Mg(1) and one Se(1) atom. In the fourth O site, O(4) is bonded in a single-bond geometry to one Se(2) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Cu(1), one Tl(1), and one Se(1) atom. In the sixth O site, O(6) is bonded in a trigonal planar geometry to one Mg(1), one Cu(1), and one Se(2) atom. In the seventh O site, O(7) is bonded in a trigonal non-coplanar geometry to one Mg(1) and two equivalent Cu(1) atoms. In the eighth O site, O(8) is bonded in a trigonal planar geometry to one Mg(1) and two equivalent Cu(1) atoms. is represented by the CIF card [CIF]
data_MgTlCu2(SeO5)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.074
_cell_length_b   6.074
_cell_length_c   8.719
_cell_angle_alpha   60.477
_cell_angle_beta   119.522
_cell_angle_gamma   116.303
_symmetry_Int_Tables_number   1
_cell_volume   234.882
_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  0.563  0.437  0.162  1.0
  Tl  Tl1  1  0.506  0.494  0.536  1.0
  Cu  Cu2  1  1.000  0.500  0.007  1.0
  Cu  Cu3  1  0.500  0.000  0.007  1.0
  Se  Se4  1  0.918  0.082  0.712  1.0
  Se  Se5  1  0.095  0.905  0.296  1.0
  O  O6  1  0.824  0.176  0.816  1.0
  O  O7  1  0.193  0.806  0.197  1.0
  O  O8  1  0.793  0.207  0.478  1.0
  O  O9  1  0.206  0.794  0.526  1.0
  O  O10  1  0.253  0.184  0.780  1.0
  O  O11  1  0.816  0.747  0.780  1.0
  O  O12  1  0.756  0.795  0.216  1.0
  O  O13  1  0.205  0.244  0.216  1.0
  O  O14  1  0.321  0.679  0.975  1.0
  O  O15  1  0.696  0.304  0.069  1.0
[/CIF]
.