The material described by Ta2Th2O9 crystallizes in the orthorhombic C222_1 space group. There are three inequivalent Th sites. In the first Th site, Th(1) is bonded in a 9-coordinate geometry to one O(4), two equivalent O(10), two equivalent O(6), two equivalent O(7), and two equivalent O(8) atoms. In the second Th site, Th(2) is bonded in a 10-coordinate geometry to two equivalent O(10), two equivalent O(5), two equivalent O(6), two equivalent O(7), and two equivalent O(9) atoms. In the third Th site, Th(3) is bonded in a 9-coordinate geometry to one O(1), one O(10), one O(11), one O(3), one O(5), one O(6), one O(7), one O(8), and one O(9) atom. There are three inequivalent Ta sites. In the first Ta site, Ta(1) is bonded to one O(1), one O(2), two equivalent O(4), and two equivalent O(7) atoms to form corner-sharing TaO6 octahedra. The corner-sharing octahedral tilt angles range from 25-62°. In the second Ta site, Ta(2) is bonded to two equivalent O(11), two equivalent O(3), and two equivalent O(5) atoms to form corner-sharing TaO6 octahedra. The corner-sharing octahedral tilt angles range from 28-47°. In the third Ta site, Ta(3) is bonded to one O(10), one O(11), one O(2), one O(5), one O(8), and one O(9) atom to form corner-sharing TaO6 octahedra. The corner-sharing octahedral tilt angles range from 28-62°. There are eleven inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to two equivalent Th(3) and one Ta(1) atom. In the second O site, O(2) is bonded in a trigonal planar geometry to one Ta(1) and two equivalent Ta(3) atoms. In the third O site, O(3) is bonded in a 2-coordinate geometry to two equivalent Th(3) and two equivalent Ta(2) atoms. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Th(1) and two equivalent Ta(1) atoms. In the fifth O site, O(11) is bonded in a distorted bent 150 degrees geometry to one Th(3), one Ta(2), and one Ta(3) atom. In the sixth O site, O(5) is bonded in a 2-coordinate geometry to one Th(2), one Th(3), one Ta(2), and one Ta(3) atom. In the seventh O site, O(6) is bonded in a trigonal planar geometry to one Th(1), one Th(2), and one Th(3) atom. In the eighth O site, O(7) is bonded in a 4-coordinate geometry to one Th(1), one Th(2), one Th(3), and one Ta(1) atom. In the ninth O site, O(8) is bonded in a distorted trigonal planar geometry to one Th(1), one Th(3), and one Ta(3) atom. In the tenth O site, O(9) is bonded in a distorted trigonal planar geometry to one Th(2), one Th(3), and one Ta(3) atom. In the eleventh O site, O(10) is bonded in a 4-coordinate geometry to one Th(1), one Th(2), one Th(3), and one Ta(3) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Th2Ta2O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.783
_cell_length_b   9.783
_cell_length_c   7.474
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   106.665
_symmetry_Int_Tables_number   1
_cell_volume   685.267
_cell_formula_units_Z   4
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  0.793  0.207  0.750  1.0
  Th  Th1  1  0.207  0.793  0.250  1.0
  Th  Th2  1  0.239  0.761  0.750  1.0
  Th  Th3  1  0.761  0.239  0.250  1.0
  Th  Th4  1  0.134  0.390  0.487  1.0
  Th  Th5  1  0.866  0.610  0.987  1.0
  Th  Th6  1  0.390  0.134  0.513  1.0
  Th  Th7  1  0.610  0.866  0.013  1.0
  Ta  Ta8  1  0.991  0.991  0.500  1.0
  Ta  Ta9  1  0.009  0.009  0.000  1.0
  Ta  Ta10  1  0.495  0.505  0.750  1.0
  Ta  Ta11  1  0.505  0.495  0.250  1.0
  Ta  Ta12  1  0.600  0.855  0.501  1.0
  Ta  Ta13  1  0.400  0.145  0.001  1.0
  Ta  Ta14  1  0.855  0.600  0.499  1.0
  Ta  Ta15  1  0.145  0.400  0.999  1.0
  O  O16  1  0.176  0.176  0.500  1.0
  O  O17  1  0.824  0.824  0.000  1.0
  O  O18  1  0.818  0.818  0.500  1.0
  O  O19  1  0.182  0.182  0.000  1.0
  O  O20  1  0.431  0.431  0.500  1.0
  O  O21  1  0.569  0.569  0.000  1.0
  O  O22  1  0.973  0.027  0.750  1.0
  O  O23  1  0.027  0.973  0.250  1.0
  O  O24  1  0.292  0.491  0.801  1.0
  O  O25  1  0.708  0.509  0.301  1.0
  O  O26  1  0.491  0.292  0.199  1.0
  O  O27  1  0.509  0.708  0.699  1.0
  O  O28  1  0.371  0.792  0.020  1.0
  O  O29  1  0.629  0.208  0.520  1.0
  O  O30  1  0.792  0.371  0.980  1.0
  O  O31  1  0.208  0.629  0.480  1.0
  O  O32  1  0.101  0.853  0.969  1.0
  O  O33  1  0.899  0.147  0.469  1.0
  O  O34  1  0.853  0.101  0.031  1.0
  O  O35  1  0.147  0.899  0.531  1.0
  O  O36  1  0.670  0.966  0.717  1.0
  O  O37  1  0.330  0.034  0.217  1.0
  O  O38  1  0.966  0.670  0.283  1.0
  O  O39  1  0.034  0.330  0.783  1.0
  O  O40  1  0.657  0.978  0.297  1.0
  O  O41  1  0.343  0.022  0.797  1.0
  O  O42  1  0.978  0.657  0.703  1.0
  O  O43  1  0.022  0.343  0.203  1.0
  O  O44  1  0.583  0.107  1.000  1.0
  O  O45  1  0.417  0.893  0.500  1.0
  O  O46  1  0.107  0.583  0.000  1.0
  O  O47  1  0.893  0.417  0.500  1.0
  O  O48  1  0.544  0.697  0.321  1.0
  O  O49  1  0.456  0.303  0.821  1.0
  O  O50  1  0.697  0.544  0.679  1.0
  O  O51  1  0.303  0.456  0.179  1.0
[/CIF]
.
The material described by Ta2Th2O9 crystallizes in the orthorhombic C222_1 space group. There are three inequivalent Th sites. In the first Th site, Th(1) is bonded in a 9-coordinate geometry to one O(4), two equivalent O(10), two equivalent O(6), two equivalent O(7), and two equivalent O(8) atoms. In the second Th site, Th(2) is bonded in a 10-coordinate geometry to two equivalent O(10), two equivalent O(5), two equivalent O(6), two equivalent O(7), and two equivalent O(9) atoms. In the third Th site, Th(3) is bonded in a 9-coordinate geometry to one O(1), one O(10), one O(11), one O(3), one O(5), one O(6), one O(7), one O(8), and one O(9) atom. There are three inequivalent Ta sites. In the first Ta site, Ta(1) is bonded to one O(1), one O(2), two equivalent O(4), and two equivalent O(7) atoms to form corner-sharing TaO6 octahedra. The corner-sharing octahedral tilt angles range from 25-62°. In the second Ta site, Ta(2) is bonded to two equivalent O(11), two equivalent O(3), and two equivalent O(5) atoms to form corner-sharing TaO6 octahedra. The corner-sharing octahedral tilt angles range from 28-47°. In the third Ta site, Ta(3) is bonded to one O(10), one O(11), one O(2), one O(5), one O(8), and one O(9) atom to form corner-sharing TaO6 octahedra. The corner-sharing octahedral tilt angles range from 28-62°. There are eleven inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to two equivalent Th(3) and one Ta(1) atom. In the second O site, O(2) is bonded in a trigonal planar geometry to one Ta(1) and two equivalent Ta(3) atoms. In the third O site, O(3) is bonded in a 2-coordinate geometry to two equivalent Th(3) and two equivalent Ta(2) atoms. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Th(1) and two equivalent Ta(1) atoms. In the fifth O site, O(11) is bonded in a distorted bent 150 degrees geometry to one Th(3), one Ta(2), and one Ta(3) atom. In the sixth O site, O(5) is bonded in a 2-coordinate geometry to one Th(2), one Th(3), one Ta(2), and one Ta(3) atom. In the seventh O site, O(6) is bonded in a trigonal planar geometry to one Th(1), one Th(2), and one Th(3) atom. In the eighth O site, O(7) is bonded in a 4-coordinate geometry to one Th(1), one Th(2), one Th(3), and one Ta(1) atom. In the ninth O site, O(8) is bonded in a distorted trigonal planar geometry to one Th(1), one Th(3), and one Ta(3) atom. In the tenth O site, O(9) is bonded in a distorted trigonal planar geometry to one Th(2), one Th(3), and one Ta(3) atom. In the eleventh O site, O(10) is bonded in a 4-coordinate geometry to one Th(1), one Th(2), one Th(3), and one Ta(3) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Th2Ta2O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.783
_cell_length_b   9.783
_cell_length_c   7.474
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   106.665
_symmetry_Int_Tables_number   1
_cell_volume   685.267
_cell_formula_units_Z   4
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  0.793  0.207  0.750  1.0
  Th  Th1  1  0.207  0.793  0.250  1.0
  Th  Th2  1  0.239  0.761  0.750  1.0
  Th  Th3  1  0.761  0.239  0.250  1.0
  Th  Th4  1  0.134  0.390  0.487  1.0
  Th  Th5  1  0.866  0.610  0.987  1.0
  Th  Th6  1  0.390  0.134  0.513  1.0
  Th  Th7  1  0.610  0.866  0.013  1.0
  Ta  Ta8  1  0.991  0.991  0.500  1.0
  Ta  Ta9  1  0.009  0.009  0.000  1.0
  Ta  Ta10  1  0.495  0.505  0.750  1.0
  Ta  Ta11  1  0.505  0.495  0.250  1.0
  Ta  Ta12  1  0.600  0.855  0.501  1.0
  Ta  Ta13  1  0.400  0.145  0.001  1.0
  Ta  Ta14  1  0.855  0.600  0.499  1.0
  Ta  Ta15  1  0.145  0.400  0.999  1.0
  O  O16  1  0.176  0.176  0.500  1.0
  O  O17  1  0.824  0.824  0.000  1.0
  O  O18  1  0.818  0.818  0.500  1.0
  O  O19  1  0.182  0.182  0.000  1.0
  O  O20  1  0.431  0.431  0.500  1.0
  O  O21  1  0.569  0.569  0.000  1.0
  O  O22  1  0.973  0.027  0.750  1.0
  O  O23  1  0.027  0.973  0.250  1.0
  O  O24  1  0.292  0.491  0.801  1.0
  O  O25  1  0.708  0.509  0.301  1.0
  O  O26  1  0.491  0.292  0.199  1.0
  O  O27  1  0.509  0.708  0.699  1.0
  O  O28  1  0.371  0.792  0.020  1.0
  O  O29  1  0.629  0.208  0.520  1.0
  O  O30  1  0.792  0.371  0.980  1.0
  O  O31  1  0.208  0.629  0.480  1.0
  O  O32  1  0.101  0.853  0.969  1.0
  O  O33  1  0.899  0.147  0.469  1.0
  O  O34  1  0.853  0.101  0.031  1.0
  O  O35  1  0.147  0.899  0.531  1.0
  O  O36  1  0.670  0.966  0.717  1.0
  O  O37  1  0.330  0.034  0.217  1.0
  O  O38  1  0.966  0.670  0.283  1.0
  O  O39  1  0.034  0.330  0.783  1.0
  O  O40  1  0.657  0.978  0.297  1.0
  O  O41  1  0.343  0.022  0.797  1.0
  O  O42  1  0.978  0.657  0.703  1.0
  O  O43  1  0.022  0.343  0.203  1.0
  O  O44  1  0.583  0.107  1.000  1.0
  O  O45  1  0.417  0.893  0.500  1.0
  O  O46  1  0.107  0.583  0.000  1.0
  O  O47  1  0.893  0.417  0.500  1.0
  O  O48  1  0.544  0.697  0.321  1.0
  O  O49  1  0.456  0.303  0.821  1.0
  O  O50  1  0.697  0.544  0.679  1.0
  O  O51  1  0.303  0.456  0.179  1.0
[/CIF]
.