The compound described by Th2Ce3O9 crystallizes in the orthorhombic Imm2 space group. Th(1) is bonded in a body-centered cubic geometry to one O(1), one O(4), three equivalent O(2), and three equivalent O(3) atoms. There are two inequivalent Ce sites. In the first Ce site, Ce(1) is bonded in a 7-coordinate geometry to one O(2), one O(3), one O(5), two equivalent O(1), and two equivalent O(4) atoms. In the second Ce site, Ce(2) is bonded in a distorted hexagonal planar geometry to two equivalent O(1), two equivalent O(4), and two equivalent O(5) atoms. There are five inequivalent O sites. In the first O site, O(1) is bonded to one Th(1), one Ce(2), and two equivalent Ce(1) atoms to form OCe3Th tetrahedra that share  a cornercorner with one O(2)CeTh3 tetrahedra, corners with three equivalent O(1)Ce3Th tetrahedra, corners with three equivalent O(4)Ce3Th tetrahedra, corners with four equivalent O(5)Ce4 tetrahedra, corners with five equivalent O(3)CeTh3 tetrahedra, edges with two equivalent O(4)Ce3Th tetrahedra, and edges with two equivalent O(2)CeTh3 tetrahedra. In the second O site, O(2) is bonded to three equivalent Th(1) and one Ce(1) atom to form OCeTh3 tetrahedra that share  a cornercorner with one O(1)Ce3Th tetrahedra,  a cornercorner with one O(5)Ce4 tetrahedra, corners with two equivalent O(3)CeTh3 tetrahedra, corners with five equivalent O(4)Ce3Th tetrahedra, corners with six equivalent O(2)CeTh3 tetrahedra, edges with two equivalent O(1)Ce3Th tetrahedra, and edges with four equivalent O(3)CeTh3 tetrahedra. In the third O site, O(3) is bonded to three equivalent Th(1) and one Ce(1) atom to form OCeTh3 tetrahedra that share  a cornercorner with one O(4)Ce3Th tetrahedra,  a cornercorner with one O(5)Ce4 tetrahedra, corners with two equivalent O(2)CeTh3 tetrahedra, corners with five equivalent O(1)Ce3Th tetrahedra, corners with six equivalent O(3)CeTh3 tetrahedra, edges with two equivalent O(4)Ce3Th tetrahedra, and edges with four equivalent O(2)CeTh3 tetrahedra. In the fourth O site, O(4) is bonded to one Th(1), one Ce(2), and two equivalent Ce(1) atoms to form OCe3Th tetrahedra that share  a cornercorner with one O(3)CeTh3 tetrahedra, corners with three equivalent O(1)Ce3Th tetrahedra, corners with three equivalent O(4)Ce3Th tetrahedra, corners with five equivalent O(2)CeTh3 tetrahedra, edges with two equivalent O(1)Ce3Th tetrahedra, edges with two equivalent O(5)Ce4 tetrahedra, and edges with two equivalent O(3)CeTh3 tetrahedra. In the fifth O site, O(5) is bonded to two equivalent Ce(1) and two equivalent Ce(2) atoms to form OCe4 tetrahedra that share corners with two equivalent O(5)Ce4 tetrahedra, corners with two equivalent O(2)CeTh3 tetrahedra, corners with two equivalent O(3)CeTh3 tetrahedra, corners with eight equivalent O(1)Ce3Th tetrahedra, and edges with four equivalent O(4)Ce3Th tetrahedra. is represented by the Crystallographic Information File (CIF) [CIF]
data_Ce3Th2O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   10.425
_cell_length_b   10.425
_cell_length_c   10.425
_cell_angle_alpha   158.326
_cell_angle_beta   148.722
_cell_angle_gamma   38.376
_symmetry_Int_Tables_number   1
_cell_volume   216.964
_cell_formula_units_Z   1
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
  Ce  Ce0  1  0.905  0.895  0.010  1.0
  Ce  Ce1  1  0.458  0.500  0.958  1.0
  Ce  Ce2  1  0.115  0.105  0.010  1.0
  Th  Th3  1  0.702  0.697  0.004  1.0
  Th  Th4  1  0.307  0.303  0.004  1.0
  O  O5  1  0.655  0.413  0.242  1.0
  O  O6  1  0.558  0.802  0.756  1.0
  O  O7  1  0.055  0.798  0.257  1.0
  O  O8  1  0.829  0.587  0.242  1.0
  O  O9  1  0.955  0.198  0.756  1.0
  O  O10  1  0.140  0.396  0.744  1.0
  O  O11  1  0.459  0.202  0.257  1.0
  O  O12  1  0.347  0.604  0.744  1.0
  O  O13  1  0.238  0.000  0.238  1.0
[/CIF]
.
The compound described by Th2Ce3O9 crystallizes in the orthorhombic Imm2 space group. Th(1) is bonded in a body-centered cubic geometry to one O(1), one O(4), three equivalent O(2), and three equivalent O(3) atoms. There are two inequivalent Ce sites. In the first Ce site, Ce(1) is bonded in a 7-coordinate geometry to one O(2), one O(3), one O(5), two equivalent O(1), and two equivalent O(4) atoms. In the second Ce site, Ce(2) is bonded in a distorted hexagonal planar geometry to two equivalent O(1), two equivalent O(4), and two equivalent O(5) atoms. There are five inequivalent O sites. In the first O site, O(1) is bonded to one Th(1), one Ce(2), and two equivalent Ce(1) atoms to form OCe3Th tetrahedra that share  a cornercorner with one O(2)CeTh3 tetrahedra, corners with three equivalent O(1)Ce3Th tetrahedra, corners with three equivalent O(4)Ce3Th tetrahedra, corners with four equivalent O(5)Ce4 tetrahedra, corners with five equivalent O(3)CeTh3 tetrahedra, edges with two equivalent O(4)Ce3Th tetrahedra, and edges with two equivalent O(2)CeTh3 tetrahedra. In the second O site, O(2) is bonded to three equivalent Th(1) and one Ce(1) atom to form OCeTh3 tetrahedra that share  a cornercorner with one O(1)Ce3Th tetrahedra,  a cornercorner with one O(5)Ce4 tetrahedra, corners with two equivalent O(3)CeTh3 tetrahedra, corners with five equivalent O(4)Ce3Th tetrahedra, corners with six equivalent O(2)CeTh3 tetrahedra, edges with two equivalent O(1)Ce3Th tetrahedra, and edges with four equivalent O(3)CeTh3 tetrahedra. In the third O site, O(3) is bonded to three equivalent Th(1) and one Ce(1) atom to form OCeTh3 tetrahedra that share  a cornercorner with one O(4)Ce3Th tetrahedra,  a cornercorner with one O(5)Ce4 tetrahedra, corners with two equivalent O(2)CeTh3 tetrahedra, corners with five equivalent O(1)Ce3Th tetrahedra, corners with six equivalent O(3)CeTh3 tetrahedra, edges with two equivalent O(4)Ce3Th tetrahedra, and edges with four equivalent O(2)CeTh3 tetrahedra. In the fourth O site, O(4) is bonded to one Th(1), one Ce(2), and two equivalent Ce(1) atoms to form OCe3Th tetrahedra that share  a cornercorner with one O(3)CeTh3 tetrahedra, corners with three equivalent O(1)Ce3Th tetrahedra, corners with three equivalent O(4)Ce3Th tetrahedra, corners with five equivalent O(2)CeTh3 tetrahedra, edges with two equivalent O(1)Ce3Th tetrahedra, edges with two equivalent O(5)Ce4 tetrahedra, and edges with two equivalent O(3)CeTh3 tetrahedra. In the fifth O site, O(5) is bonded to two equivalent Ce(1) and two equivalent Ce(2) atoms to form OCe4 tetrahedra that share corners with two equivalent O(5)Ce4 tetrahedra, corners with two equivalent O(2)CeTh3 tetrahedra, corners with two equivalent O(3)CeTh3 tetrahedra, corners with eight equivalent O(1)Ce3Th tetrahedra, and edges with four equivalent O(4)Ce3Th tetrahedra. is represented by the Crystallographic Information File (CIF) [CIF]
data_Ce3Th2O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   10.425
_cell_length_b   10.425
_cell_length_c   10.425
_cell_angle_alpha   158.326
_cell_angle_beta   148.722
_cell_angle_gamma   38.376
_symmetry_Int_Tables_number   1
_cell_volume   216.964
_cell_formula_units_Z   1
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
  Ce  Ce0  1  0.905  0.895  0.010  1.0
  Ce  Ce1  1  0.458  0.500  0.958  1.0
  Ce  Ce2  1  0.115  0.105  0.010  1.0
  Th  Th3  1  0.702  0.697  0.004  1.0
  Th  Th4  1  0.307  0.303  0.004  1.0
  O  O5  1  0.655  0.413  0.242  1.0
  O  O6  1  0.558  0.802  0.756  1.0
  O  O7  1  0.055  0.798  0.257  1.0
  O  O8  1  0.829  0.587  0.242  1.0
  O  O9  1  0.955  0.198  0.756  1.0
  O  O10  1  0.140  0.396  0.744  1.0
  O  O11  1  0.459  0.202  0.257  1.0
  O  O12  1  0.347  0.604  0.744  1.0
  O  O13  1  0.238  0.000  0.238  1.0
[/CIF]
.