The crystal structure described by Ba2Fe2TlAlO7 crystallizes in the triclinic P1 space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 9-coordinate geometry to one O(5), two equivalent O(2), two equivalent O(3), and four equivalent O(1) atoms. In the second Ba site, Ba(2) is bonded in a 9-coordinate geometry to one O(5), two equivalent O(4), two equivalent O(6), and four equivalent O(7) atoms. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), two equivalent O(2), and two equivalent O(3) atoms to form distorted corner-sharing FeO5 square pyramids. In the second Fe site, Fe(2) is bonded to one O(7), two equivalent O(4), and two equivalent O(6) atoms to form distorted corner-sharing FeO5 square pyramids. Tl(1) is bonded in a see-saw-like geometry to one O(1), one O(7), and two equivalent O(5) atoms. Al(1) is bonded in a square co-planar geometry to one O(2), one O(3), one O(4), and one O(6) atom. There are seven inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Ba(1), one Fe(1), and one Tl(1) atom to form a mixture of distorted edge and corner-sharing OBa4TlFe octahedra. The corner-sharing octahedral tilt angles range from 17-19°. In the second O site, O(2) is bonded in a 5-coordinate geometry to two equivalent Ba(1), two equivalent Fe(1), and one Al(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to two equivalent Ba(1), two equivalent Fe(1), and one Al(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to two equivalent Ba(2), two equivalent Fe(2), and one Al(1) atom. In the fifth O site, O(5) is bonded in a see-saw-like geometry to one Ba(1), one Ba(2), and two equivalent Tl(1) atoms. In the sixth O site, O(6) is bonded in a 5-coordinate geometry to two equivalent Ba(2), two equivalent Fe(2), and one Al(1) atom. In the seventh O site, O(7) is bonded to four equivalent Ba(2), one Fe(2), and one Tl(1) atom to form a mixture of distorted edge and corner-sharing OBa4TlFe octahedra. The corner-sharing octahedral tilt angles range from 15-19°. is represented by the Crystallographic Information File (CIF) [CIF]
data_Ba2AlTlFe2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.037
_cell_length_b   4.103
_cell_length_c   12.028
_cell_angle_alpha   84.211
_cell_angle_beta   84.438
_cell_angle_gamma   87.304
_symmetry_Int_Tables_number   1
_cell_volume   197.111
_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  0.437  0.443  0.216  1.0
  Ba  Ba1  1  0.565  0.577  0.784  1.0
  Al  Al2  1  0.502  0.509  0.500  1.0
  Tl  Tl3  1  0.006  0.073  0.999  1.0
  Fe  Fe4  1  0.920  0.923  0.378  1.0
  Fe  Fe5  1  0.084  0.093  0.625  1.0
  O  O6  1  0.953  0.940  0.180  1.0
  O  O7  1  0.854  0.404  0.396  1.0
  O  O8  1  0.405  0.857  0.396  1.0
  O  O9  1  0.599  0.164  0.606  1.0
  O  O10  1  0.488  0.368  0.998  1.0
  O  O11  1  0.148  0.613  0.604  1.0
  O  O12  1  0.040  0.035  0.817  1.0
[/CIF]
.
The crystal structure described by Ba2Fe2TlAlO7 crystallizes in the triclinic P1 space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 9-coordinate geometry to one O(5), two equivalent O(2), two equivalent O(3), and four equivalent O(1) atoms. In the second Ba site, Ba(2) is bonded in a 9-coordinate geometry to one O(5), two equivalent O(4), two equivalent O(6), and four equivalent O(7) atoms. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), two equivalent O(2), and two equivalent O(3) atoms to form distorted corner-sharing FeO5 square pyramids. In the second Fe site, Fe(2) is bonded to one O(7), two equivalent O(4), and two equivalent O(6) atoms to form distorted corner-sharing FeO5 square pyramids. Tl(1) is bonded in a see-saw-like geometry to one O(1), one O(7), and two equivalent O(5) atoms. Al(1) is bonded in a square co-planar geometry to one O(2), one O(3), one O(4), and one O(6) atom. There are seven inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Ba(1), one Fe(1), and one Tl(1) atom to form a mixture of distorted edge and corner-sharing OBa4TlFe octahedra. The corner-sharing octahedral tilt angles range from 17-19°. In the second O site, O(2) is bonded in a 5-coordinate geometry to two equivalent Ba(1), two equivalent Fe(1), and one Al(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to two equivalent Ba(1), two equivalent Fe(1), and one Al(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to two equivalent Ba(2), two equivalent Fe(2), and one Al(1) atom. In the fifth O site, O(5) is bonded in a see-saw-like geometry to one Ba(1), one Ba(2), and two equivalent Tl(1) atoms. In the sixth O site, O(6) is bonded in a 5-coordinate geometry to two equivalent Ba(2), two equivalent Fe(2), and one Al(1) atom. In the seventh O site, O(7) is bonded to four equivalent Ba(2), one Fe(2), and one Tl(1) atom to form a mixture of distorted edge and corner-sharing OBa4TlFe octahedra. The corner-sharing octahedral tilt angles range from 15-19°. is represented by the Crystallographic Information File (CIF) [CIF]
data_Ba2AlTlFe2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.037
_cell_length_b   4.103
_cell_length_c   12.028
_cell_angle_alpha   84.211
_cell_angle_beta   84.438
_cell_angle_gamma   87.304
_symmetry_Int_Tables_number   1
_cell_volume   197.111
_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  0.437  0.443  0.216  1.0
  Ba  Ba1  1  0.565  0.577  0.784  1.0
  Al  Al2  1  0.502  0.509  0.500  1.0
  Tl  Tl3  1  0.006  0.073  0.999  1.0
  Fe  Fe4  1  0.920  0.923  0.378  1.0
  Fe  Fe5  1  0.084  0.093  0.625  1.0
  O  O6  1  0.953  0.940  0.180  1.0
  O  O7  1  0.854  0.404  0.396  1.0
  O  O8  1  0.405  0.857  0.396  1.0
  O  O9  1  0.599  0.164  0.606  1.0
  O  O10  1  0.488  0.368  0.998  1.0
  O  O11  1  0.148  0.613  0.604  1.0
  O  O12  1  0.040  0.035  0.817  1.0
[/CIF]
.