The structure described by BiTa7O19 crystallizes in the hexagonal P-6c2 space group. There are two inequivalent Ta sites. In the first Ta site, Ta(1) is bonded in an octahedral geometry to six equivalent O(5) atoms. In the second Ta site, Ta(2) is bonded in a 7-coordinate geometry to one O(2), one O(3), one O(4), one O(5), and three equivalent O(1) atoms. Bi(1) is bonded in a 8-coordinate geometry to two equivalent O(3) and six equivalent O(5) atoms. There are five inequivalent O sites. In the first O site, O(3) is bonded in a distorted trigonal non-coplanar geometry to three equivalent Ta(2) and one Bi(1) atom. In the second O site, O(4) is bonded in a bent 150 degrees geometry to two equivalent Ta(2) atoms. In the third O site, O(5) is bonded in a distorted trigonal non-coplanar geometry to one Ta(1), one Ta(2), and one Bi(1) atom. In the fourth O site, O(1) is bonded in a distorted bent 150 degrees geometry to three equivalent Ta(2) atoms. In the fifth O site, O(2) is bonded in a trigonal planar geometry to three equivalent Ta(2) atoms. is represented by the CIF card [CIF]
data_Ta7BiO19
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.273
_cell_length_b   6.273
_cell_length_c   20.217
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   688.986
_cell_formula_units_Z   2
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
  Ta  Ta0  1  0.000  0.000  0.000  1.0
  Ta  Ta1  1  0.000  0.000  0.500  1.0
  Ta  Ta2  1  0.667  0.694  0.844  1.0
  Ta  Ta3  1  0.306  0.974  0.844  1.0
  Ta  Ta4  1  0.026  0.333  0.844  1.0
  Ta  Ta5  1  0.667  0.694  0.656  1.0
  Ta  Ta6  1  0.306  0.974  0.656  1.0
  Ta  Ta7  1  0.026  0.333  0.656  1.0
  Ta  Ta8  1  0.667  0.974  0.344  1.0
  Ta  Ta9  1  0.306  0.333  0.344  1.0
  Ta  Ta10  1  0.026  0.694  0.344  1.0
  Ta  Ta11  1  0.667  0.974  0.156  1.0
  Ta  Ta12  1  0.306  0.333  0.156  1.0
  Ta  Ta13  1  0.026  0.694  0.156  1.0
  Bi  Bi14  1  0.333  0.667  0.000  1.0
  Bi  Bi15  1  0.333  0.667  0.500  1.0
  O  O16  1  0.667  0.086  0.847  1.0
  O  O17  1  0.914  0.581  0.847  1.0
  O  O18  1  0.419  0.333  0.847  1.0
  O  O19  1  0.667  0.086  0.653  1.0
  O  O20  1  0.914  0.581  0.653  1.0
  O  O21  1  0.419  0.333  0.653  1.0
  O  O22  1  0.667  0.581  0.347  1.0
  O  O23  1  0.914  0.333  0.347  1.0
  O  O24  1  0.419  0.086  0.347  1.0
  O  O25  1  0.667  0.581  0.153  1.0
  O  O26  1  0.914  0.333  0.153  1.0
  O  O27  1  0.419  0.086  0.153  1.0
  O  O28  1  0.000  0.000  0.833  1.0
  O  O29  1  0.000  0.000  0.667  1.0
  O  O30  1  0.000  0.000  0.333  1.0
  O  O31  1  0.000  0.000  0.167  1.0
  O  O32  1  0.333  0.667  0.866  1.0
  O  O33  1  0.333  0.667  0.634  1.0
  O  O34  1  0.333  0.667  0.366  1.0
  O  O35  1  0.333  0.667  0.134  1.0
  O  O36  1  0.625  0.708  0.750  1.0
  O  O37  1  0.292  0.917  0.750  1.0
  O  O38  1  0.083  0.375  0.750  1.0
  O  O39  1  0.625  0.917  0.250  1.0
  O  O40  1  0.292  0.375  0.250  1.0
  O  O41  1  0.083  0.708  0.250  1.0
  O  O42  1  0.716  0.762  0.944  1.0
  O  O43  1  0.238  0.954  0.944  1.0
  O  O44  1  0.046  0.284  0.944  1.0
  O  O45  1  0.716  0.762  0.556  1.0
  O  O46  1  0.238  0.954  0.556  1.0
  O  O47  1  0.046  0.284  0.556  1.0
  O  O48  1  0.716  0.954  0.444  1.0
  O  O49  1  0.238  0.284  0.444  1.0
  O  O50  1  0.046  0.762  0.444  1.0
  O  O51  1  0.716  0.954  0.056  1.0
  O  O52  1  0.238  0.284  0.056  1.0
  O  O53  1  0.046  0.762  0.056  1.0
[/CIF]
.
The structure described by BiTa7O19 crystallizes in the hexagonal P-6c2 space group. There are two inequivalent Ta sites. In the first Ta site, Ta(1) is bonded in an octahedral geometry to six equivalent O(5) atoms. In the second Ta site, Ta(2) is bonded in a 7-coordinate geometry to one O(2), one O(3), one O(4), one O(5), and three equivalent O(1) atoms. Bi(1) is bonded in a 8-coordinate geometry to two equivalent O(3) and six equivalent O(5) atoms. There are five inequivalent O sites. In the first O site, O(3) is bonded in a distorted trigonal non-coplanar geometry to three equivalent Ta(2) and one Bi(1) atom. In the second O site, O(4) is bonded in a bent 150 degrees geometry to two equivalent Ta(2) atoms. In the third O site, O(5) is bonded in a distorted trigonal non-coplanar geometry to one Ta(1), one Ta(2), and one Bi(1) atom. In the fourth O site, O(1) is bonded in a distorted bent 150 degrees geometry to three equivalent Ta(2) atoms. In the fifth O site, O(2) is bonded in a trigonal planar geometry to three equivalent Ta(2) atoms. is represented by the CIF card [CIF]
data_Ta7BiO19
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.273
_cell_length_b   6.273
_cell_length_c   20.217
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   688.986
_cell_formula_units_Z   2
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
  Ta  Ta0  1  0.000  0.000  0.000  1.0
  Ta  Ta1  1  0.000  0.000  0.500  1.0
  Ta  Ta2  1  0.667  0.694  0.844  1.0
  Ta  Ta3  1  0.306  0.974  0.844  1.0
  Ta  Ta4  1  0.026  0.333  0.844  1.0
  Ta  Ta5  1  0.667  0.694  0.656  1.0
  Ta  Ta6  1  0.306  0.974  0.656  1.0
  Ta  Ta7  1  0.026  0.333  0.656  1.0
  Ta  Ta8  1  0.667  0.974  0.344  1.0
  Ta  Ta9  1  0.306  0.333  0.344  1.0
  Ta  Ta10  1  0.026  0.694  0.344  1.0
  Ta  Ta11  1  0.667  0.974  0.156  1.0
  Ta  Ta12  1  0.306  0.333  0.156  1.0
  Ta  Ta13  1  0.026  0.694  0.156  1.0
  Bi  Bi14  1  0.333  0.667  0.000  1.0
  Bi  Bi15  1  0.333  0.667  0.500  1.0
  O  O16  1  0.667  0.086  0.847  1.0
  O  O17  1  0.914  0.581  0.847  1.0
  O  O18  1  0.419  0.333  0.847  1.0
  O  O19  1  0.667  0.086  0.653  1.0
  O  O20  1  0.914  0.581  0.653  1.0
  O  O21  1  0.419  0.333  0.653  1.0
  O  O22  1  0.667  0.581  0.347  1.0
  O  O23  1  0.914  0.333  0.347  1.0
  O  O24  1  0.419  0.086  0.347  1.0
  O  O25  1  0.667  0.581  0.153  1.0
  O  O26  1  0.914  0.333  0.153  1.0
  O  O27  1  0.419  0.086  0.153  1.0
  O  O28  1  0.000  0.000  0.833  1.0
  O  O29  1  0.000  0.000  0.667  1.0
  O  O30  1  0.000  0.000  0.333  1.0
  O  O31  1  0.000  0.000  0.167  1.0
  O  O32  1  0.333  0.667  0.866  1.0
  O  O33  1  0.333  0.667  0.634  1.0
  O  O34  1  0.333  0.667  0.366  1.0
  O  O35  1  0.333  0.667  0.134  1.0
  O  O36  1  0.625  0.708  0.750  1.0
  O  O37  1  0.292  0.917  0.750  1.0
  O  O38  1  0.083  0.375  0.750  1.0
  O  O39  1  0.625  0.917  0.250  1.0
  O  O40  1  0.292  0.375  0.250  1.0
  O  O41  1  0.083  0.708  0.250  1.0
  O  O42  1  0.716  0.762  0.944  1.0
  O  O43  1  0.238  0.954  0.944  1.0
  O  O44  1  0.046  0.284  0.944  1.0
  O  O45  1  0.716  0.762  0.556  1.0
  O  O46  1  0.238  0.954  0.556  1.0
  O  O47  1  0.046  0.284  0.556  1.0
  O  O48  1  0.716  0.954  0.444  1.0
  O  O49  1  0.238  0.284  0.444  1.0
  O  O50  1  0.046  0.762  0.444  1.0
  O  O51  1  0.716  0.954  0.056  1.0
  O  O52  1  0.238  0.284  0.056  1.0
  O  O53  1  0.046  0.762  0.056  1.0
[/CIF]
.