The crystal structure described by ThNb4O12 crystallizes in the orthorhombic Immm space group. There are two inequivalent Th sites. In the first Th site, Th(1) is bonded to two equivalent O(1), two equivalent O(2), and eight equivalent O(6) atoms to form ThO12 cuboctahedra that share corners with two equivalent Th(1)O12 cuboctahedra, faces with four equivalent Th(2)O12 cuboctahedra, faces with four equivalent Nb(1)O6 octahedra, and faces with four equivalent Nb(4)O6 octahedra. In the second Th site, Th(2) is bonded to one O(1), one O(4), two equivalent O(2), four equivalent O(3), and four equivalent O(6) atoms to form distorted ThO12 cuboctahedra that share corners with three equivalent Th(2)O12 cuboctahedra, faces with two equivalent Th(1)O12 cuboctahedra, faces with two equivalent Nb(2)O6 octahedra, faces with two equivalent Nb(4)O6 octahedra, and faces with four equivalent Nb(1)O6 octahedra. There are four inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to one O(2), one O(5), two equivalent O(3), and two equivalent O(6) atoms to form distorted NbO6 octahedra that share  a cornercorner with one Nb(1)O6 octahedra, corners with two equivalent Nb(4)O6 octahedra, corners with three equivalent Nb(2)O6 octahedra,  a faceface with one Th(1)O12 cuboctahedra, and faces with two equivalent Th(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 5-25°. In the second Nb site, Nb(2) is bonded to one O(4), one O(5), two equivalent O(3), and two equivalent O(7) atoms to form distorted NbO6 octahedra that share  a cornercorner with one Nb(2)O6 octahedra, corners with two equivalent Nb(3)O6 octahedra, corners with three equivalent Nb(1)O6 octahedra, and  a faceface with one Th(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 5-24°. In the third Nb site, Nb(3) is bonded to one O(8), one O(9), and four equivalent O(7) atoms to form corner-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles range from 0-5°. In the fourth Nb site, Nb(4) is bonded to one O(1), one O(9), and four equivalent O(6) atoms to form distorted NbO6 octahedra that share  a cornercorner with one Nb(3)O6 octahedra,  a cornercorner with one Nb(4)O6 octahedra, corners with four equivalent Nb(1)O6 octahedra, faces with two equivalent Th(1)O12 cuboctahedra, and faces with two equivalent Th(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-25°. There are nine inequivalent O sites. In the first O site, O(3) is bonded in a 3-coordinate geometry to one Th(2), one Nb(1), and one Nb(2) atom. In the second O site, O(4) is bonded in a 3-coordinate geometry to one Th(2) and two equivalent Nb(2) atoms. In the third O site, O(5) is bonded in a linear geometry to one Nb(1) and one Nb(2) atom. In the fourth O site, O(6) is bonded in a 4-coordinate geometry to one Th(1), one Th(2), one Nb(1), and one Nb(4) atom. In the fifth O site, O(7) is bonded in a linear geometry to one Nb(2) and one Nb(3) atom. In the sixth O site, O(8) is bonded in a linear geometry to two equivalent Nb(3) atoms. In the seventh O site, O(9) is bonded in a linear geometry to one Nb(3) and one Nb(4) atom. In the eighth O site, O(1) is bonded in a distorted linear geometry to two equivalent Th(1), two equivalent Th(2), and two equivalent Nb(4) atoms. In the ninth O site, O(2) is bonded to one Th(1), two equivalent Th(2), and two equivalent Nb(1) atoms to form distorted corner-sharing OTh3Nb2 square pyramids. is represented by the CIF file [CIF]
data_ThNb4O12
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   11.976
_cell_length_b   11.976
_cell_length_c   11.976
_cell_angle_alpha   152.943
_cell_angle_beta   96.087
_cell_angle_gamma   90.195
_symmetry_Int_Tables_number   1
_cell_volume   758.488
_cell_formula_units_Z   3
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  0.000  0.000  0.000  1.0
  Th  Th1  1  0.828  0.328  0.500  1.0
  Th  Th2  1  0.172  0.672  0.500  1.0
  Nb  Nb3  1  0.960  0.827  0.134  1.0
  Nb  Nb4  1  0.693  0.827  0.866  1.0
  Nb  Nb5  1  0.534  0.157  0.376  1.0
  Nb  Nb6  1  0.781  0.157  0.624  1.0
  Nb  Nb7  1  0.620  0.500  0.120  1.0
  Nb  Nb8  1  0.136  0.500  0.636  1.0
  Nb  Nb9  1  0.380  0.500  0.880  1.0
  Nb  Nb10  1  0.864  0.500  0.364  1.0
  Nb  Nb11  1  0.219  0.843  0.376  1.0
  Nb  Nb12  1  0.466  0.843  0.624  1.0
  Nb  Nb13  1  0.307  0.173  0.134  1.0
  Nb  Nb14  1  0.040  0.173  0.866  1.0
  O  O15  1  0.000  0.500  0.500  1.0
  O  O16  1  0.846  0.846  0.000  1.0
  O  O17  1  0.648  0.493  0.619  1.0
  O  O18  1  0.873  0.028  0.381  1.0
  O  O19  1  0.648  0.028  0.155  1.0
  O  O20  1  0.873  0.493  0.845  1.0
  O  O21  1  0.682  0.182  0.500  1.0
  O  O22  1  0.423  0.170  0.252  1.0
  O  O23  1  0.918  0.170  0.748  1.0
  O  O24  1  0.188  0.328  0.355  1.0
  O  O25  1  0.973  0.328  0.140  1.0
  O  O26  1  0.707  0.337  0.874  1.0
  O  O27  1  0.463  0.337  0.630  1.0
  O  O28  1  0.188  0.833  0.860  1.0
  O  O29  1  0.973  0.833  0.645  1.0
  O  O30  1  0.463  0.832  0.126  1.0
  O  O31  1  0.707  0.832  0.370  1.0
  O  O32  1  0.500  0.500  0.000  1.0
  O  O33  1  0.252  0.500  0.752  1.0
  O  O34  1  0.748  0.500  0.248  1.0
  O  O35  1  0.293  0.168  0.630  1.0
  O  O36  1  0.027  0.167  0.355  1.0
  O  O37  1  0.537  0.663  0.370  1.0
  O  O38  1  0.293  0.663  0.126  1.0
  O  O39  1  0.537  0.168  0.874  1.0
  O  O40  1  0.027  0.672  0.860  1.0
  O  O41  1  0.812  0.167  0.140  1.0
  O  O42  1  0.812  0.672  0.645  1.0
  O  O43  1  0.577  0.830  0.748  1.0
  O  O44  1  0.082  0.830  0.252  1.0
  O  O45  1  0.318  0.818  0.500  1.0
  O  O46  1  0.127  0.507  0.155  1.0
  O  O47  1  0.352  0.507  0.381  1.0
  O  O48  1  0.352  0.972  0.845  1.0
  O  O49  1  0.127  0.972  0.619  1.0
  O  O50  1  0.154  0.154  0.000  1.0
[/CIF]
.
The crystal structure described by ThNb4O12 crystallizes in the orthorhombic Immm space group. There are two inequivalent Th sites. In the first Th site, Th(1) is bonded to two equivalent O(1), two equivalent O(2), and eight equivalent O(6) atoms to form ThO12 cuboctahedra that share corners with two equivalent Th(1)O12 cuboctahedra, faces with four equivalent Th(2)O12 cuboctahedra, faces with four equivalent Nb(1)O6 octahedra, and faces with four equivalent Nb(4)O6 octahedra. In the second Th site, Th(2) is bonded to one O(1), one O(4), two equivalent O(2), four equivalent O(3), and four equivalent O(6) atoms to form distorted ThO12 cuboctahedra that share corners with three equivalent Th(2)O12 cuboctahedra, faces with two equivalent Th(1)O12 cuboctahedra, faces with two equivalent Nb(2)O6 octahedra, faces with two equivalent Nb(4)O6 octahedra, and faces with four equivalent Nb(1)O6 octahedra. There are four inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to one O(2), one O(5), two equivalent O(3), and two equivalent O(6) atoms to form distorted NbO6 octahedra that share  a cornercorner with one Nb(1)O6 octahedra, corners with two equivalent Nb(4)O6 octahedra, corners with three equivalent Nb(2)O6 octahedra,  a faceface with one Th(1)O12 cuboctahedra, and faces with two equivalent Th(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 5-25°. In the second Nb site, Nb(2) is bonded to one O(4), one O(5), two equivalent O(3), and two equivalent O(7) atoms to form distorted NbO6 octahedra that share  a cornercorner with one Nb(2)O6 octahedra, corners with two equivalent Nb(3)O6 octahedra, corners with three equivalent Nb(1)O6 octahedra, and  a faceface with one Th(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 5-24°. In the third Nb site, Nb(3) is bonded to one O(8), one O(9), and four equivalent O(7) atoms to form corner-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles range from 0-5°. In the fourth Nb site, Nb(4) is bonded to one O(1), one O(9), and four equivalent O(6) atoms to form distorted NbO6 octahedra that share  a cornercorner with one Nb(3)O6 octahedra,  a cornercorner with one Nb(4)O6 octahedra, corners with four equivalent Nb(1)O6 octahedra, faces with two equivalent Th(1)O12 cuboctahedra, and faces with two equivalent Th(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-25°. There are nine inequivalent O sites. In the first O site, O(3) is bonded in a 3-coordinate geometry to one Th(2), one Nb(1), and one Nb(2) atom. In the second O site, O(4) is bonded in a 3-coordinate geometry to one Th(2) and two equivalent Nb(2) atoms. In the third O site, O(5) is bonded in a linear geometry to one Nb(1) and one Nb(2) atom. In the fourth O site, O(6) is bonded in a 4-coordinate geometry to one Th(1), one Th(2), one Nb(1), and one Nb(4) atom. In the fifth O site, O(7) is bonded in a linear geometry to one Nb(2) and one Nb(3) atom. In the sixth O site, O(8) is bonded in a linear geometry to two equivalent Nb(3) atoms. In the seventh O site, O(9) is bonded in a linear geometry to one Nb(3) and one Nb(4) atom. In the eighth O site, O(1) is bonded in a distorted linear geometry to two equivalent Th(1), two equivalent Th(2), and two equivalent Nb(4) atoms. In the ninth O site, O(2) is bonded to one Th(1), two equivalent Th(2), and two equivalent Nb(1) atoms to form distorted corner-sharing OTh3Nb2 square pyramids. is represented by the CIF file [CIF]
data_ThNb4O12
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   11.976
_cell_length_b   11.976
_cell_length_c   11.976
_cell_angle_alpha   152.943
_cell_angle_beta   96.087
_cell_angle_gamma   90.195
_symmetry_Int_Tables_number   1
_cell_volume   758.488
_cell_formula_units_Z   3
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  0.000  0.000  0.000  1.0
  Th  Th1  1  0.828  0.328  0.500  1.0
  Th  Th2  1  0.172  0.672  0.500  1.0
  Nb  Nb3  1  0.960  0.827  0.134  1.0
  Nb  Nb4  1  0.693  0.827  0.866  1.0
  Nb  Nb5  1  0.534  0.157  0.376  1.0
  Nb  Nb6  1  0.781  0.157  0.624  1.0
  Nb  Nb7  1  0.620  0.500  0.120  1.0
  Nb  Nb8  1  0.136  0.500  0.636  1.0
  Nb  Nb9  1  0.380  0.500  0.880  1.0
  Nb  Nb10  1  0.864  0.500  0.364  1.0
  Nb  Nb11  1  0.219  0.843  0.376  1.0
  Nb  Nb12  1  0.466  0.843  0.624  1.0
  Nb  Nb13  1  0.307  0.173  0.134  1.0
  Nb  Nb14  1  0.040  0.173  0.866  1.0
  O  O15  1  0.000  0.500  0.500  1.0
  O  O16  1  0.846  0.846  0.000  1.0
  O  O17  1  0.648  0.493  0.619  1.0
  O  O18  1  0.873  0.028  0.381  1.0
  O  O19  1  0.648  0.028  0.155  1.0
  O  O20  1  0.873  0.493  0.845  1.0
  O  O21  1  0.682  0.182  0.500  1.0
  O  O22  1  0.423  0.170  0.252  1.0
  O  O23  1  0.918  0.170  0.748  1.0
  O  O24  1  0.188  0.328  0.355  1.0
  O  O25  1  0.973  0.328  0.140  1.0
  O  O26  1  0.707  0.337  0.874  1.0
  O  O27  1  0.463  0.337  0.630  1.0
  O  O28  1  0.188  0.833  0.860  1.0
  O  O29  1  0.973  0.833  0.645  1.0
  O  O30  1  0.463  0.832  0.126  1.0
  O  O31  1  0.707  0.832  0.370  1.0
  O  O32  1  0.500  0.500  0.000  1.0
  O  O33  1  0.252  0.500  0.752  1.0
  O  O34  1  0.748  0.500  0.248  1.0
  O  O35  1  0.293  0.168  0.630  1.0
  O  O36  1  0.027  0.167  0.355  1.0
  O  O37  1  0.537  0.663  0.370  1.0
  O  O38  1  0.293  0.663  0.126  1.0
  O  O39  1  0.537  0.168  0.874  1.0
  O  O40  1  0.027  0.672  0.860  1.0
  O  O41  1  0.812  0.167  0.140  1.0
  O  O42  1  0.812  0.672  0.645  1.0
  O  O43  1  0.577  0.830  0.748  1.0
  O  O44  1  0.082  0.830  0.252  1.0
  O  O45  1  0.318  0.818  0.500  1.0
  O  O46  1  0.127  0.507  0.155  1.0
  O  O47  1  0.352  0.507  0.381  1.0
  O  O48  1  0.352  0.972  0.845  1.0
  O  O49  1  0.127  0.972  0.619  1.0
  O  O50  1  0.154  0.154  0.000  1.0
[/CIF]
.