The material described by Sr2YFe2TlO7 crystallizes in the tetragonal P4/mmm space group. Sr(1) is bonded to one O(3) and four equivalent O(2) atoms to form distorted SrO5 square pyramids that share corners with five equivalent Sr(1)O5 square pyramids, corners with four equivalent Fe(1)O5 trigonal bipyramids, edges with four equivalent Tl(1)O6 octahedra, and edges with four equivalent Sr(1)O5 square pyramids. Y(1) is bonded in a body-centered cubic geometry to eight equivalent O(1) atoms. Fe(1) is bonded to one O(2) and four equivalent O(1) atoms to form distorted FeO5 trigonal bipyramids that share  a cornercorner with one Tl(1)O6 octahedra, corners with four equivalent Sr(1)O5 square pyramids, and corners with four equivalent Fe(1)O5 trigonal bipyramids. The corner-sharing octahedra are not tilted. Tl(1) is bonded to two equivalent O(2) and four equivalent O(3) atoms to form TlO6 octahedra that share corners with four equivalent Tl(1)O6 octahedra, corners with two equivalent Fe(1)O5 trigonal bipyramids, edges with four equivalent Tl(1)O6 octahedra, and edges with eight equivalent Sr(1)O5 square pyramids. The corner-sharing octahedra are not tilted. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Y(1) and two equivalent Fe(1) atoms. In the second O site, O(2) is bonded to four equivalent Sr(1), one Fe(1), and one Tl(1) atom to form distorted OSr4TlFe octahedra that share corners with five equivalent O(2)Sr4TlFe octahedra, edges with four equivalent O(3)Sr2Tl4 octahedra, and edges with four equivalent O(2)Sr4TlFe octahedra. The corner-sharing octahedral tilt angles range from 0-9°. In the third O site, O(3) is bonded to two equivalent Sr(1) and four equivalent Tl(1) atoms to form OSr2Tl4 octahedra that share corners with four equivalent O(3)Sr2Tl4 octahedra, edges with four equivalent O(3)Sr2Tl4 octahedra, and edges with eight equivalent O(2)Sr4TlFe octahedra. The corner-sharing octahedra are not tilted. is represented by the CIF file [CIF]
data_Sr2YTlFe2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.873
_cell_length_b   3.873
_cell_length_c   13.004
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   195.056
_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
  Sr  Sr0  1  0.500  0.500  0.811  1.0
  Sr  Sr1  1  0.500  0.500  0.189  1.0
  Y  Y2  1  0.500  0.500  0.500  1.0
  Tl  Tl3  1  0.000  0.000  0.000  1.0
  Fe  Fe4  1  0.000  0.000  0.648  1.0
  Fe  Fe5  1  0.000  0.000  0.352  1.0
  O  O6  1  0.500  0.000  0.609  1.0
  O  O7  1  0.000  0.500  0.609  1.0
  O  O8  1  0.500  0.000  0.391  1.0
  O  O9  1  0.000  0.500  0.391  1.0
  O  O10  1  0.000  0.000  0.795  1.0
  O  O11  1  0.000  0.000  0.205  1.0
  O  O12  1  0.500  0.500  0.000  1.0
[/CIF]
.
The material described by Sr2YFe2TlO7 crystallizes in the tetragonal P4/mmm space group. Sr(1) is bonded to one O(3) and four equivalent O(2) atoms to form distorted SrO5 square pyramids that share corners with five equivalent Sr(1)O5 square pyramids, corners with four equivalent Fe(1)O5 trigonal bipyramids, edges with four equivalent Tl(1)O6 octahedra, and edges with four equivalent Sr(1)O5 square pyramids. Y(1) is bonded in a body-centered cubic geometry to eight equivalent O(1) atoms. Fe(1) is bonded to one O(2) and four equivalent O(1) atoms to form distorted FeO5 trigonal bipyramids that share  a cornercorner with one Tl(1)O6 octahedra, corners with four equivalent Sr(1)O5 square pyramids, and corners with four equivalent Fe(1)O5 trigonal bipyramids. The corner-sharing octahedra are not tilted. Tl(1) is bonded to two equivalent O(2) and four equivalent O(3) atoms to form TlO6 octahedra that share corners with four equivalent Tl(1)O6 octahedra, corners with two equivalent Fe(1)O5 trigonal bipyramids, edges with four equivalent Tl(1)O6 octahedra, and edges with eight equivalent Sr(1)O5 square pyramids. The corner-sharing octahedra are not tilted. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Y(1) and two equivalent Fe(1) atoms. In the second O site, O(2) is bonded to four equivalent Sr(1), one Fe(1), and one Tl(1) atom to form distorted OSr4TlFe octahedra that share corners with five equivalent O(2)Sr4TlFe octahedra, edges with four equivalent O(3)Sr2Tl4 octahedra, and edges with four equivalent O(2)Sr4TlFe octahedra. The corner-sharing octahedral tilt angles range from 0-9°. In the third O site, O(3) is bonded to two equivalent Sr(1) and four equivalent Tl(1) atoms to form OSr2Tl4 octahedra that share corners with four equivalent O(3)Sr2Tl4 octahedra, edges with four equivalent O(3)Sr2Tl4 octahedra, and edges with eight equivalent O(2)Sr4TlFe octahedra. The corner-sharing octahedra are not tilted. is represented by the CIF file [CIF]
data_Sr2YTlFe2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.873
_cell_length_b   3.873
_cell_length_c   13.004
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   195.056
_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
  Sr  Sr0  1  0.500  0.500  0.811  1.0
  Sr  Sr1  1  0.500  0.500  0.189  1.0
  Y  Y2  1  0.500  0.500  0.500  1.0
  Tl  Tl3  1  0.000  0.000  0.000  1.0
  Fe  Fe4  1  0.000  0.000  0.648  1.0
  Fe  Fe5  1  0.000  0.000  0.352  1.0
  O  O6  1  0.500  0.000  0.609  1.0
  O  O7  1  0.000  0.500  0.609  1.0
  O  O8  1  0.500  0.000  0.391  1.0
  O  O9  1  0.000  0.500  0.391  1.0
  O  O10  1  0.000  0.000  0.795  1.0
  O  O11  1  0.000  0.000  0.205  1.0
  O  O12  1  0.500  0.500  0.000  1.0
[/CIF]
.