The compound described by Ba2TlAlSn2O7 crystallizes in the tetragonal P4/mmm space group. Ba(1) is bonded to one O(3) and four equivalent O(1) atoms to form distorted BaO5 square pyramids that share corners with four equivalent Sn(1)O5 square pyramids, corners with five equivalent Ba(1)O5 square pyramids, and edges with four equivalent Ba(1)O5 square pyramids. Tl(1) is bonded in a distorted linear geometry to two equivalent O(1) atoms. Al(1) is bonded in a body-centered cubic geometry to eight equivalent O(2) atoms. Sn(1) is bonded to one O(1) and four equivalent O(2) atoms to form SnO5 square pyramids that share corners with four equivalent Ba(1)O5 square pyramids and corners with four equivalent Sn(1)O5 square pyramids. There are three inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Ba(1), one Tl(1), and one Sn(1) atom to form a mixture of distorted edge and corner-sharing OBa4TlSn octahedra. The corner-sharing octahedral tilt angles range from 0-13°. In the second O site, O(2) is bonded in a 4-coordinate geometry to two equivalent Al(1) and two equivalent Sn(1) atoms. In the third O site, O(3) is bonded in a linear geometry to two equivalent Ba(1) atoms. is represented by the CIF file [CIF]
data_Ba2AlTlSn2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.156
_cell_length_b   4.156
_cell_length_c   12.966
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   223.978
_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  0.500  0.500  0.191  1.0
  Ba  Ba1  1  0.500  0.500  0.809  1.0
  Al  Al2  1  0.500  0.500  0.500  1.0
  Tl  Tl3  1  0.000  0.000  0.000  1.0
  Sn  Sn4  1  0.000  0.000  0.374  1.0
  Sn  Sn5  1  0.000  0.000  0.626  1.0
  O  O6  1  0.000  0.000  0.216  1.0
  O  O7  1  0.000  0.500  0.401  1.0
  O  O8  1  0.500  0.000  0.401  1.0
  O  O9  1  0.500  0.000  0.599  1.0
  O  O10  1  0.500  0.500  0.000  1.0
  O  O11  1  0.000  0.500  0.599  1.0
  O  O12  1  0.000  0.000  0.784  1.0
[/CIF]
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The compound described by Ba2TlAlSn2O7 crystallizes in the tetragonal P4/mmm space group. Ba(1) is bonded to one O(3) and four equivalent O(1) atoms to form distorted BaO5 square pyramids that share corners with four equivalent Sn(1)O5 square pyramids, corners with five equivalent Ba(1)O5 square pyramids, and edges with four equivalent Ba(1)O5 square pyramids. Tl(1) is bonded in a distorted linear geometry to two equivalent O(1) atoms. Al(1) is bonded in a body-centered cubic geometry to eight equivalent O(2) atoms. Sn(1) is bonded to one O(1) and four equivalent O(2) atoms to form SnO5 square pyramids that share corners with four equivalent Ba(1)O5 square pyramids and corners with four equivalent Sn(1)O5 square pyramids. There are three inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Ba(1), one Tl(1), and one Sn(1) atom to form a mixture of distorted edge and corner-sharing OBa4TlSn octahedra. The corner-sharing octahedral tilt angles range from 0-13°. In the second O site, O(2) is bonded in a 4-coordinate geometry to two equivalent Al(1) and two equivalent Sn(1) atoms. In the third O site, O(3) is bonded in a linear geometry to two equivalent Ba(1) atoms. is represented by the CIF file [CIF]
data_Ba2AlTlSn2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.156
_cell_length_b   4.156
_cell_length_c   12.966
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   223.978
_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  0.500  0.500  0.191  1.0
  Ba  Ba1  1  0.500  0.500  0.809  1.0
  Al  Al2  1  0.500  0.500  0.500  1.0
  Tl  Tl3  1  0.000  0.000  0.000  1.0
  Sn  Sn4  1  0.000  0.000  0.374  1.0
  Sn  Sn5  1  0.000  0.000  0.626  1.0
  O  O6  1  0.000  0.000  0.216  1.0
  O  O7  1  0.000  0.500  0.401  1.0
  O  O8  1  0.500  0.000  0.401  1.0
  O  O9  1  0.500  0.000  0.599  1.0
  O  O10  1  0.500  0.500  0.000  1.0
  O  O11  1  0.000  0.500  0.599  1.0
  O  O12  1  0.000  0.000  0.784  1.0
[/CIF]
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