The structure described by TaBi(P2O7)2 crystallizes in the monoclinic P2_1/c space group. Ta(1) is bonded to two equivalent O(1), two equivalent O(4), and two equivalent O(6) atoms to form TaO6 octahedra that share corners with two equivalent P(2)O4 tetrahedra and corners with four equivalent P(1)O4 tetrahedra. Bi(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(5) atoms to form BiO6 octahedra that share corners with two equivalent P(1)O4 tetrahedra and corners with four equivalent P(2)O4 tetrahedra. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(4), one O(5), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one Bi(1)O6 octahedra, corners with two equivalent Ta(1)O6 octahedra, and  a cornercorner with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 11-22°. In the second P site, P(2) is bonded to one O(2), one O(3), one O(6), and one O(8) atom to form PO4 tetrahedra that share  a cornercorner with one Ta(1)O6 octahedra, corners with two equivalent Bi(1)O6 octahedra, and  a cornercorner with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 21-34°. There are eight inequivalent O sites. In the first O site, O(7) is bonded in a linear geometry to two equivalent P(1) atoms. In the second O site, O(8) is bonded in a linear geometry to two equivalent P(2) atoms. In the third O site, O(1) is bonded in a linear geometry to one Ta(1) and one P(1) atom. In the fourth O site, O(2) is bonded in a distorted bent 150 degrees geometry to one Bi(1) and one P(2) atom. In the fifth O site, O(3) is bonded in a bent 150 degrees geometry to one Bi(1) and one P(2) atom. In the sixth O site, O(4) is bonded in a linear geometry to one Ta(1) and one P(1) atom. In the seventh O site, O(5) is bonded in a distorted bent 150 degrees geometry to one Bi(1) and one P(1) atom. In the eighth O site, O(6) is bonded in a bent 150 degrees geometry to one Ta(1) and one P(2) atom. is represented by the CIF file [CIF]
data_TaBi(P2O7)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.428
_cell_length_b   8.442
_cell_length_c   8.590
_cell_angle_alpha   88.725
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   610.997
_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  0.500  0.500  0.000  1.0
  Bi  Bi2  1  0.000  0.500  0.500  1.0
  Bi  Bi3  1  0.500  0.000  0.500  1.0
  P  P4  1  0.616  0.113  0.088  1.0
  P  P5  1  0.116  0.387  0.912  1.0
  P  P6  1  0.412  0.601  0.372  1.0
  P  P7  1  0.912  0.899  0.628  1.0
  P  P8  1  0.384  0.887  0.912  1.0
  P  P9  1  0.884  0.613  0.088  1.0
  P  P10  1  0.588  0.399  0.628  1.0
  P  P11  1  0.088  0.101  0.372  1.0
  O  O12  1  0.780  0.075  0.023  1.0
  O  O13  1  0.280  0.425  0.977  1.0
  O  O14  1  0.238  0.586  0.395  1.0
  O  O15  1  0.738  0.914  0.605  1.0
  O  O16  1  0.478  0.765  0.369  1.0
  O  O17  1  0.571  0.280  0.032  1.0
  O  O18  1  0.071  0.220  0.968  1.0
  O  O19  1  0.978  0.735  0.631  1.0
  O  O20  1  0.106  0.411  0.741  1.0
  O  O21  1  0.464  0.517  0.221  1.0
  O  O22  1  0.606  0.089  0.259  1.0
  O  O23  1  0.964  0.983  0.779  1.0
  O  O24  1  0.220  0.925  0.977  1.0
  O  O25  1  0.720  0.575  0.023  1.0
  O  O26  1  0.762  0.414  0.605  1.0
  O  O27  1  0.262  0.086  0.395  1.0
  O  O28  1  0.522  0.235  0.631  1.0
  O  O29  1  0.429  0.720  0.968  1.0
  O  O30  1  0.929  0.780  0.032  1.0
  O  O31  1  0.022  0.265  0.369  1.0
  O  O32  1  0.894  0.589  0.259  1.0
  O  O33  1  0.536  0.483  0.779  1.0
  O  O34  1  0.394  0.911  0.741  1.0
  O  O35  1  0.036  0.017  0.221  1.0
  O  O36  1  0.500  0.000  0.000  1.0
  O  O37  1  0.000  0.500  0.000  1.0
  O  O38  1  0.500  0.500  0.500  1.0
  O  O39  1  0.000  0.000  0.500  1.0
[/CIF]
.
The structure described by TaBi(P2O7)2 crystallizes in the monoclinic P2_1/c space group. Ta(1) is bonded to two equivalent O(1), two equivalent O(4), and two equivalent O(6) atoms to form TaO6 octahedra that share corners with two equivalent P(2)O4 tetrahedra and corners with four equivalent P(1)O4 tetrahedra. Bi(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(5) atoms to form BiO6 octahedra that share corners with two equivalent P(1)O4 tetrahedra and corners with four equivalent P(2)O4 tetrahedra. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(4), one O(5), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one Bi(1)O6 octahedra, corners with two equivalent Ta(1)O6 octahedra, and  a cornercorner with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 11-22°. In the second P site, P(2) is bonded to one O(2), one O(3), one O(6), and one O(8) atom to form PO4 tetrahedra that share  a cornercorner with one Ta(1)O6 octahedra, corners with two equivalent Bi(1)O6 octahedra, and  a cornercorner with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 21-34°. There are eight inequivalent O sites. In the first O site, O(7) is bonded in a linear geometry to two equivalent P(1) atoms. In the second O site, O(8) is bonded in a linear geometry to two equivalent P(2) atoms. In the third O site, O(1) is bonded in a linear geometry to one Ta(1) and one P(1) atom. In the fourth O site, O(2) is bonded in a distorted bent 150 degrees geometry to one Bi(1) and one P(2) atom. In the fifth O site, O(3) is bonded in a bent 150 degrees geometry to one Bi(1) and one P(2) atom. In the sixth O site, O(4) is bonded in a linear geometry to one Ta(1) and one P(1) atom. In the seventh O site, O(5) is bonded in a distorted bent 150 degrees geometry to one Bi(1) and one P(1) atom. In the eighth O site, O(6) is bonded in a bent 150 degrees geometry to one Ta(1) and one P(2) atom. is represented by the CIF file [CIF]
data_TaBi(P2O7)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.428
_cell_length_b   8.442
_cell_length_c   8.590
_cell_angle_alpha   88.725
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   610.997
_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  0.500  0.500  0.000  1.0
  Bi  Bi2  1  0.000  0.500  0.500  1.0
  Bi  Bi3  1  0.500  0.000  0.500  1.0
  P  P4  1  0.616  0.113  0.088  1.0
  P  P5  1  0.116  0.387  0.912  1.0
  P  P6  1  0.412  0.601  0.372  1.0
  P  P7  1  0.912  0.899  0.628  1.0
  P  P8  1  0.384  0.887  0.912  1.0
  P  P9  1  0.884  0.613  0.088  1.0
  P  P10  1  0.588  0.399  0.628  1.0
  P  P11  1  0.088  0.101  0.372  1.0
  O  O12  1  0.780  0.075  0.023  1.0
  O  O13  1  0.280  0.425  0.977  1.0
  O  O14  1  0.238  0.586  0.395  1.0
  O  O15  1  0.738  0.914  0.605  1.0
  O  O16  1  0.478  0.765  0.369  1.0
  O  O17  1  0.571  0.280  0.032  1.0
  O  O18  1  0.071  0.220  0.968  1.0
  O  O19  1  0.978  0.735  0.631  1.0
  O  O20  1  0.106  0.411  0.741  1.0
  O  O21  1  0.464  0.517  0.221  1.0
  O  O22  1  0.606  0.089  0.259  1.0
  O  O23  1  0.964  0.983  0.779  1.0
  O  O24  1  0.220  0.925  0.977  1.0
  O  O25  1  0.720  0.575  0.023  1.0
  O  O26  1  0.762  0.414  0.605  1.0
  O  O27  1  0.262  0.086  0.395  1.0
  O  O28  1  0.522  0.235  0.631  1.0
  O  O29  1  0.429  0.720  0.968  1.0
  O  O30  1  0.929  0.780  0.032  1.0
  O  O31  1  0.022  0.265  0.369  1.0
  O  O32  1  0.894  0.589  0.259  1.0
  O  O33  1  0.536  0.483  0.779  1.0
  O  O34  1  0.394  0.911  0.741  1.0
  O  O35  1  0.036  0.017  0.221  1.0
  O  O36  1  0.500  0.000  0.000  1.0
  O  O37  1  0.000  0.500  0.000  1.0
  O  O38  1  0.500  0.500  0.500  1.0
  O  O39  1  0.000  0.000  0.500  1.0
[/CIF]
.