The material described by Ba2Ta6Te2O21 crystallizes in the monoclinic C2/m space group. Ba(1) is bonded in a 11-coordinate geometry to one O(2), two equivalent O(4), two equivalent O(6), two equivalent O(7), and four equivalent O(8) atoms. There are three inequivalent Ta sites. In the first Ta site, Ta(1) is bonded to one O(2), one O(3), two equivalent O(4), and two equivalent O(5) atoms to form corner-sharing TaO6 octahedra. The corner-sharing octahedral tilt angles range from 0-13°. In the second Ta site, Ta(2) is bonded to one O(1), one O(7), two equivalent O(4), and two equivalent O(6) atoms to form a mixture of distorted corner and edge-sharing TaO6 octahedra. The corner-sharing octahedral tilt angles range from 10-13°. In the third Ta site, Ta(3) is bonded to one O(1), one O(2), two equivalent O(5), and two equivalent O(8) atoms to form corner-sharing TaO6 octahedra. The corner-sharing octahedral tilt angles range from 7-13°. Te(1) is bonded in a distorted T-shaped geometry to one O(7) and two equivalent O(8) atoms. There are eight inequivalent O sites. In the first O site, O(7) is bonded in a 4-coordinate geometry to two equivalent Ba(1), one Ta(2), and one Te(1) atom. In the second O site, O(8) is bonded in a 4-coordinate geometry to two equivalent Ba(1), one Ta(3), and one Te(1) atom. In the third O site, O(1) is bonded in a linear geometry to one Ta(2) and one Ta(3) atom. In the fourth O site, O(2) is bonded in a distorted linear geometry to one Ba(1), one Ta(1), and one Ta(3) atom. In the fifth O site, O(3) is bonded in a linear geometry to two equivalent Ta(1) atoms. In the sixth O site, O(4) is bonded in a linear geometry to one Ba(1), one Ta(1), and one Ta(2) atom. In the seventh O site, O(5) is bonded in a linear geometry to one Ta(1) and one Ta(3) atom. In the eighth O site, O(6) is bonded to two equivalent Ba(1) and two equivalent Ta(2) atoms to form distorted edge-sharing OBa2Ta2 tetrahedra. is represented by the CIF file [CIF]
data_Ba2Ta6Te2O21
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.918
_cell_length_b   8.918
_cell_length_c   9.743
_cell_angle_alpha   83.560
_cell_angle_beta   83.560
_cell_angle_gamma   37.593
_symmetry_Int_Tables_number   1
_cell_volume   469.329
_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  0.138  0.138  0.472  1.0
  Ba  Ba1  1  0.862  0.862  0.528  1.0
  Ta  Ta2  1  0.901  0.901  0.918  1.0
  Ta  Ta3  1  0.099  0.099  0.082  1.0
  Ta  Ta4  1  0.479  0.479  0.664  1.0
  Ta  Ta5  1  0.521  0.521  0.336  1.0
  Ta  Ta6  1  0.676  0.676  0.828  1.0
  Ta  Ta7  1  0.324  0.324  0.172  1.0
  Te  Te8  1  0.274  0.274  0.753  1.0
  Te  Te9  1  0.726  0.726  0.247  1.0
  O  O10  1  0.419  0.419  0.278  1.0
  O  O11  1  0.581  0.581  0.722  1.0
  O  O12  1  0.210  0.210  0.151  1.0
  O  O13  1  0.790  0.790  0.849  1.0
  O  O14  1  0.000  0.000  0.000  1.0
  O  O15  1  0.176  0.693  0.780  1.0
  O  O16  1  0.307  0.824  0.220  1.0
  O  O17  1  0.824  0.307  0.220  1.0
  O  O18  1  0.693  0.176  0.780  1.0
  O  O19  1  0.896  0.394  0.947  1.0
  O  O20  1  0.279  0.721  0.500  1.0
  O  O21  1  0.721  0.279  0.500  1.0
  O  O22  1  0.642  0.642  0.396  1.0
  O  O23  1  0.358  0.358  0.604  1.0
  O  O24  1  0.542  0.023  0.330  1.0
  O  O25  1  0.977  0.458  0.670  1.0
  O  O26  1  0.458  0.977  0.670  1.0
  O  O27  1  0.023  0.542  0.330  1.0
  O  O28  1  0.394  0.896  0.947  1.0
  O  O29  1  0.104  0.606  0.053  1.0
  O  O30  1  0.606  0.104  0.053  1.0
[/CIF]
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The material described by Ba2Ta6Te2O21 crystallizes in the monoclinic C2/m space group. Ba(1) is bonded in a 11-coordinate geometry to one O(2), two equivalent O(4), two equivalent O(6), two equivalent O(7), and four equivalent O(8) atoms. There are three inequivalent Ta sites. In the first Ta site, Ta(1) is bonded to one O(2), one O(3), two equivalent O(4), and two equivalent O(5) atoms to form corner-sharing TaO6 octahedra. The corner-sharing octahedral tilt angles range from 0-13°. In the second Ta site, Ta(2) is bonded to one O(1), one O(7), two equivalent O(4), and two equivalent O(6) atoms to form a mixture of distorted corner and edge-sharing TaO6 octahedra. The corner-sharing octahedral tilt angles range from 10-13°. In the third Ta site, Ta(3) is bonded to one O(1), one O(2), two equivalent O(5), and two equivalent O(8) atoms to form corner-sharing TaO6 octahedra. The corner-sharing octahedral tilt angles range from 7-13°. Te(1) is bonded in a distorted T-shaped geometry to one O(7) and two equivalent O(8) atoms. There are eight inequivalent O sites. In the first O site, O(7) is bonded in a 4-coordinate geometry to two equivalent Ba(1), one Ta(2), and one Te(1) atom. In the second O site, O(8) is bonded in a 4-coordinate geometry to two equivalent Ba(1), one Ta(3), and one Te(1) atom. In the third O site, O(1) is bonded in a linear geometry to one Ta(2) and one Ta(3) atom. In the fourth O site, O(2) is bonded in a distorted linear geometry to one Ba(1), one Ta(1), and one Ta(3) atom. In the fifth O site, O(3) is bonded in a linear geometry to two equivalent Ta(1) atoms. In the sixth O site, O(4) is bonded in a linear geometry to one Ba(1), one Ta(1), and one Ta(2) atom. In the seventh O site, O(5) is bonded in a linear geometry to one Ta(1) and one Ta(3) atom. In the eighth O site, O(6) is bonded to two equivalent Ba(1) and two equivalent Ta(2) atoms to form distorted edge-sharing OBa2Ta2 tetrahedra. is represented by the CIF file [CIF]
data_Ba2Ta6Te2O21
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.918
_cell_length_b   8.918
_cell_length_c   9.743
_cell_angle_alpha   83.560
_cell_angle_beta   83.560
_cell_angle_gamma   37.593
_symmetry_Int_Tables_number   1
_cell_volume   469.329
_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  0.138  0.138  0.472  1.0
  Ba  Ba1  1  0.862  0.862  0.528  1.0
  Ta  Ta2  1  0.901  0.901  0.918  1.0
  Ta  Ta3  1  0.099  0.099  0.082  1.0
  Ta  Ta4  1  0.479  0.479  0.664  1.0
  Ta  Ta5  1  0.521  0.521  0.336  1.0
  Ta  Ta6  1  0.676  0.676  0.828  1.0
  Ta  Ta7  1  0.324  0.324  0.172  1.0
  Te  Te8  1  0.274  0.274  0.753  1.0
  Te  Te9  1  0.726  0.726  0.247  1.0
  O  O10  1  0.419  0.419  0.278  1.0
  O  O11  1  0.581  0.581  0.722  1.0
  O  O12  1  0.210  0.210  0.151  1.0
  O  O13  1  0.790  0.790  0.849  1.0
  O  O14  1  0.000  0.000  0.000  1.0
  O  O15  1  0.176  0.693  0.780  1.0
  O  O16  1  0.307  0.824  0.220  1.0
  O  O17  1  0.824  0.307  0.220  1.0
  O  O18  1  0.693  0.176  0.780  1.0
  O  O19  1  0.896  0.394  0.947  1.0
  O  O20  1  0.279  0.721  0.500  1.0
  O  O21  1  0.721  0.279  0.500  1.0
  O  O22  1  0.642  0.642  0.396  1.0
  O  O23  1  0.358  0.358  0.604  1.0
  O  O24  1  0.542  0.023  0.330  1.0
  O  O25  1  0.977  0.458  0.670  1.0
  O  O26  1  0.458  0.977  0.670  1.0
  O  O27  1  0.023  0.542  0.330  1.0
  O  O28  1  0.394  0.896  0.947  1.0
  O  O29  1  0.104  0.606  0.053  1.0
  O  O30  1  0.606  0.104  0.053  1.0
[/CIF]
.