data_Ba2TlFe2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.76
_cell_length_b   3.76
_cell_length_c   13.41
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Ba2TlFe2O7
_chemical_formula_sum   'Ba2 Tl1 Fe2 O7'
_cell_volume   189.83
_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
  Ba  Ba0  1  0.0  0.0  0.77  1.0
  Ba  Ba1  1  0.0  0.0  0.64  1.0
  Tl  Tl2  1  0.88  0.88  0.0  1.0
  Fe  Fe3  1  0.88  0.88  0.27  1.0
  Fe  Fe4  1  0.88  0.88  0.14  1.0
  O  O5  1  0.0  0.0  0.0  1.0
  O  O6  1  0.88  0.0  0.95  1.0
  O  O7  1  0.0  0.88  0.95  1.0
  O  O8  1  0.88  0.0  0.46  1.0
  O  O9  1  0.0  0.88  0.46  1.0
  O  O10  1  0.88  0.88  0.08  1.0
  O  O11  1  0.88  0.88  0.33  1.0

data_Ba2TlFe2O7
_symmetry_space_group_name_H-M   Cm
_cell_length_a   5.32
_cell_length_b   5.32
_cell_length_c   13.41
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   Ba2TlFe2O7
_chemical_formula_sum   'Ba4 Tl2 Fe4 O14'
_cell_volume   379.65
_cell_formula_units_Z   2
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  'x, -y, z'
  3  'x+1/2, y+1/2, z'
  4  'x+1/2, -y+1/2, 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
  Ba  Ba0  2  0.0  0.0  0.64  1.0
  Ba  Ba1  2  0.0  0.0  0.77  1.0
  Tl  Tl2  2  0.38  0.5  0.0  1.0
  Fe  Fe3  2  0.38  0.5  0.14  1.0
  Fe  Fe4  2  0.38  0.5  0.27  1.0
  O  O5  4  0.44  0.44  0.46  1.0
  O  O6  4  0.44  0.44  0.95  1.0
  O  O7  2  0.0  0.0  0.0  1.0
  O  O8  2  0.38  0.5  0.08  1.0
  O  O9  2  0.38  0.5  0.33  1.0

Ba Ba Tl Fe Fe O O O O O O O
Ba Ba Tl Fe Fe O O O O O O O 0 1 o o o 2 7 + o - 2 6 o + - 2 5 + + o 3 11 o o o 4 10 o o o 5 6 - o - 5 7 o - - 6 7 + - o 8 9 + - o 
Ba2Fe2TlO7 crystallizes in the monoclinic Cm space group. The structure is zero-dimensional and consists of two Ba2Fe2TlO7 clusters. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 3-coordinate geometry to one Ba(2) and two equivalent O(2) atoms. The Ba(1)-Ba(2) bond length is 1.71 Å. Both Ba(1)-O(2) bond lengths are 2.52 Å. In the second Ba site, Ba(2) is bonded in a 3-coordinate geometry to one Ba(1) and two equivalent O(3) atoms. Both Ba(2)-O(3) bond lengths are 2.52 Å. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a single-bond geometry to one O(5) atom. The Fe(1)-O(5) bond length is 0.79 Å. In the second Fe site, Fe(2) is bonded in a single-bond geometry to one O(4) atom. The Fe(2)-O(4) bond length is 0.79 Å. Tl(1) is bonded in a single-bond geometry to one O(1), one O(4), and two equivalent O(2) atoms. The Tl(1)-O(1) bond length is 0.63 Å. The Tl(1)-O(4) bond length is 1.06 Å. Both Tl(1)-O(2) bond lengths are 0.77 Å. There are five inequivalent O sites. In the first O site, O(1) is bonded in a single-bond geometry to one Tl(1) and two equivalent O(2) atoms. Both O(1)-O(2) bond lengths are 0.77 Å. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Ba(1), one Tl(1), one O(1), and one O(2) atom. The O(2)-O(2) bond length is 0.63 Å. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Ba(2), one O(3), and one O(5) atom. The O(3)-O(3) bond length is 0.63 Å. The O(3)-O(5) bond length is 1.74 Å. In the fourth O site, O(4) is bonded in a linear geometry to one Fe(2) and one Tl(1) atom. In the fifth O site, O(5) is bonded in a single-bond geometry to one Fe(1) and two equivalent O(3) atoms.