The crystal structure described by ThTa2O7 crystallizes in the monoclinic C2/m space group. Th(1) is bonded in a 10-coordinate geometry to one O(3), one O(4), one O(7), two equivalent O(2), two equivalent O(6), and three equivalent O(5) atoms. There are two inequivalent Ta sites. In the first Ta site, Ta(1) is bonded to one O(6), one O(7), two equivalent O(1), and two equivalent O(3) atoms to form distorted TaO6 octahedra that share corners with two equivalent Ta(1)O6 octahedra,  a cornercorner with one Ta(2)O7 pentagonal bipyramid,  an edgeedge with one Ta(1)O6 octahedra, and  an edgeedge with one Ta(2)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles are 22°. In the second Ta site, Ta(2) is bonded to one O(1), one O(5), one O(7), two equivalent O(2), and two equivalent O(4) atoms to form TaO7 pentagonal bipyramids that share  a cornercorner with one Ta(1)O6 octahedra, corners with two equivalent Ta(2)O7 pentagonal bipyramids,  an edgeedge with one Ta(1)O6 octahedra, and  an edgeedge with one Ta(2)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles are 39°. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Ta(2) and two equivalent Ta(1) atoms. In the second O site, O(2) is bonded in a distorted water-like geometry to two equivalent Th(1) and two equivalent Ta(2) atoms. In the third O site, O(3) is bonded in a distorted bent 150 degrees geometry to one Th(1) and two equivalent Ta(1) atoms. In the fourth O site, O(4) is bonded in a 2-coordinate geometry to one Th(1) and two equivalent Ta(2) atoms. In the fifth O site, O(5) is bonded to three equivalent Th(1) and one Ta(2) atom to form a mixture of edge and corner-sharing OTh3Ta tetrahedra. In the sixth O site, O(6) is bonded in a trigonal non-coplanar geometry to two equivalent Th(1) and one Ta(1) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Th(1), one Ta(1), and one Ta(2) atom. is represented by the CIF card [CIF]
data_ThTa2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.980
_cell_length_b   7.980
_cell_length_c   8.368
_cell_angle_alpha   84.181
_cell_angle_beta   84.181
_cell_angle_gamma   28.217
_symmetry_Int_Tables_number   1
_cell_volume   250.581
_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
  Th  Th0  1  0.312  0.312  0.667  1.0
  Th  Th1  1  0.688  0.688  0.333  1.0
  Ta  Ta2  1  0.108  0.108  0.020  1.0
  Ta  Ta3  1  0.892  0.892  0.980  1.0
  Ta  Ta4  1  0.071  0.071  0.634  1.0
  Ta  Ta5  1  0.929  0.929  0.366  1.0
  O  O6  1  0.013  0.013  0.859  1.0
  O  O7  1  0.987  0.987  0.141  1.0
  O  O8  1  0.057  0.057  0.392  1.0
  O  O9  1  0.943  0.943  0.608  1.0
  O  O10  1  0.393  0.393  0.935  1.0
  O  O11  1  0.607  0.607  0.065  1.0
  O  O12  1  0.585  0.585  0.611  1.0
  O  O13  1  0.415  0.415  0.389  1.0
  O  O14  1  0.805  0.805  0.497  1.0
  O  O15  1  0.195  0.195  0.503  1.0
  O  O16  1  0.803  0.803  0.834  1.0
  O  O17  1  0.197  0.197  0.166  1.0
  O  O18  1  0.832  0.832  0.193  1.0
  O  O19  1  0.168  0.168  0.807  1.0
[/CIF]
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The crystal structure described by ThTa2O7 crystallizes in the monoclinic C2/m space group. Th(1) is bonded in a 10-coordinate geometry to one O(3), one O(4), one O(7), two equivalent O(2), two equivalent O(6), and three equivalent O(5) atoms. There are two inequivalent Ta sites. In the first Ta site, Ta(1) is bonded to one O(6), one O(7), two equivalent O(1), and two equivalent O(3) atoms to form distorted TaO6 octahedra that share corners with two equivalent Ta(1)O6 octahedra,  a cornercorner with one Ta(2)O7 pentagonal bipyramid,  an edgeedge with one Ta(1)O6 octahedra, and  an edgeedge with one Ta(2)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles are 22°. In the second Ta site, Ta(2) is bonded to one O(1), one O(5), one O(7), two equivalent O(2), and two equivalent O(4) atoms to form TaO7 pentagonal bipyramids that share  a cornercorner with one Ta(1)O6 octahedra, corners with two equivalent Ta(2)O7 pentagonal bipyramids,  an edgeedge with one Ta(1)O6 octahedra, and  an edgeedge with one Ta(2)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles are 39°. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Ta(2) and two equivalent Ta(1) atoms. In the second O site, O(2) is bonded in a distorted water-like geometry to two equivalent Th(1) and two equivalent Ta(2) atoms. In the third O site, O(3) is bonded in a distorted bent 150 degrees geometry to one Th(1) and two equivalent Ta(1) atoms. In the fourth O site, O(4) is bonded in a 2-coordinate geometry to one Th(1) and two equivalent Ta(2) atoms. In the fifth O site, O(5) is bonded to three equivalent Th(1) and one Ta(2) atom to form a mixture of edge and corner-sharing OTh3Ta tetrahedra. In the sixth O site, O(6) is bonded in a trigonal non-coplanar geometry to two equivalent Th(1) and one Ta(1) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Th(1), one Ta(1), and one Ta(2) atom. is represented by the CIF card [CIF]
data_ThTa2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.980
_cell_length_b   7.980
_cell_length_c   8.368
_cell_angle_alpha   84.181
_cell_angle_beta   84.181
_cell_angle_gamma   28.217
_symmetry_Int_Tables_number   1
_cell_volume   250.581
_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
  Th  Th0  1  0.312  0.312  0.667  1.0
  Th  Th1  1  0.688  0.688  0.333  1.0
  Ta  Ta2  1  0.108  0.108  0.020  1.0
  Ta  Ta3  1  0.892  0.892  0.980  1.0
  Ta  Ta4  1  0.071  0.071  0.634  1.0
  Ta  Ta5  1  0.929  0.929  0.366  1.0
  O  O6  1  0.013  0.013  0.859  1.0
  O  O7  1  0.987  0.987  0.141  1.0
  O  O8  1  0.057  0.057  0.392  1.0
  O  O9  1  0.943  0.943  0.608  1.0
  O  O10  1  0.393  0.393  0.935  1.0
  O  O11  1  0.607  0.607  0.065  1.0
  O  O12  1  0.585  0.585  0.611  1.0
  O  O13  1  0.415  0.415  0.389  1.0
  O  O14  1  0.805  0.805  0.497  1.0
  O  O15  1  0.195  0.195  0.503  1.0
  O  O16  1  0.803  0.803  0.834  1.0
  O  O17  1  0.197  0.197  0.166  1.0
  O  O18  1  0.832  0.832  0.193  1.0
  O  O19  1  0.168  0.168  0.807  1.0
[/CIF]
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