The structure described by Ce2O3 crystallizes in the monoclinic C2/m space group. There are three inequivalent Ce sites. In the first Ce site, Ce(1) is bonded in a 7-coordinate geometry to two equivalent O(2), two equivalent O(3), and three equivalent O(1) atoms. In the second Ce site, Ce(2) is bonded in a 7-coordinate geometry to one O(1), one O(5), two equivalent O(2), and three equivalent O(4) atoms. In the third Ce site, Ce(3) is bonded in a 6-coordinate geometry to one O(2), one O(4), two equivalent O(3), and two equivalent O(5) atoms. There are five inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Ce(2) and three equivalent Ce(1) atoms. In the second O site, O(2) is bonded to one Ce(3), two equivalent Ce(1), and two equivalent Ce(2) atoms to form distorted OCe5 square pyramids that share corners with two equivalent O(3)Ce4 tetrahedra, corners with five equivalent O(4)Ce4 tetrahedra, edges with two equivalent O(5)Ce6 octahedra, edges with two equivalent O(2)Ce5 square pyramids,  an edgeedge with one O(4)Ce4 tetrahedra, and edges with two equivalent O(3)Ce4 tetrahedra. In the third O site, O(3) is bonded to two equivalent Ce(1) and two equivalent Ce(3) atoms to form OCe4 tetrahedra that share corners with two equivalent O(5)Ce6 octahedra, corners with two equivalent O(2)Ce5 square pyramids, corners with two equivalent O(3)Ce4 tetrahedra, corners with two equivalent O(4)Ce4 tetrahedra,  an edgeedge with one O(5)Ce6 octahedra, edges with two equivalent O(2)Ce5 square pyramids, and  an edgeedge with one O(3)Ce4 tetrahedra. The corner-sharing octahedral tilt angles are 14°. In the fourth O site, O(4) is bonded to one Ce(3) and three equivalent Ce(2) atoms to form OCe4 tetrahedra that share  a cornercorner with one O(5)Ce6 octahedra, corners with five equivalent O(2)Ce5 square pyramids, corners with two equivalent O(3)Ce4 tetrahedra, corners with two equivalent O(4)Ce4 tetrahedra, edges with two equivalent O(5)Ce6 octahedra,  an edgeedge with one O(2)Ce5 square pyramid, and edges with two equivalent O(4)Ce4 tetrahedra. The corner-sharing octahedral tilt angles are 51°. In the fifth O site, O(5) is bonded to two equivalent Ce(2) and four equivalent Ce(3) atoms to form OCe6 octahedra that share corners with two equivalent O(4)Ce4 tetrahedra, corners with four equivalent O(3)Ce4 tetrahedra, edges with two equivalent O(5)Ce6 octahedra, edges with four equivalent O(2)Ce5 square pyramids, edges with two equivalent O(3)Ce4 tetrahedra, and edges with four equivalent O(4)Ce4 tetrahedra. is represented by the CIF file [CIF]
data_Ce2O3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.703
_cell_length_b   7.457
_cell_length_c   9.002
_cell_angle_alpha   99.770
_cell_angle_beta   90.000
_cell_angle_gamma   104.377
_symmetry_Int_Tables_number   1
_cell_volume   237.062
_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
  Ce  Ce0  1  0.366  0.732  0.510  1.0
  Ce  Ce1  1  0.310  0.620  0.861  1.0
  Ce  Ce2  1  0.634  0.268  0.490  1.0
  Ce  Ce3  1  0.033  0.065  0.813  1.0
  Ce  Ce4  1  0.967  0.935  0.187  1.0
  Ce  Ce5  1  0.690  0.380  0.139  1.0
  O  O6  1  0.797  0.594  0.373  1.0
  O  O7  1  0.127  0.254  0.285  1.0
  O  O8  1  0.527  0.054  0.657  1.0
  O  O9  1  0.203  0.406  0.627  1.0
  O  O10  1  0.176  0.351  0.973  1.0
  O  O11  1  0.824  0.649  0.027  1.0
  O  O12  1  0.473  0.946  0.343  1.0
  O  O13  1  0.500  0.000  0.000  1.0
  O  O14  1  0.873  0.746  0.715  1.0
[/CIF]
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The structure described by Ce2O3 crystallizes in the monoclinic C2/m space group. There are three inequivalent Ce sites. In the first Ce site, Ce(1) is bonded in a 7-coordinate geometry to two equivalent O(2), two equivalent O(3), and three equivalent O(1) atoms. In the second Ce site, Ce(2) is bonded in a 7-coordinate geometry to one O(1), one O(5), two equivalent O(2), and three equivalent O(4) atoms. In the third Ce site, Ce(3) is bonded in a 6-coordinate geometry to one O(2), one O(4), two equivalent O(3), and two equivalent O(5) atoms. There are five inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Ce(2) and three equivalent Ce(1) atoms. In the second O site, O(2) is bonded to one Ce(3), two equivalent Ce(1), and two equivalent Ce(2) atoms to form distorted OCe5 square pyramids that share corners with two equivalent O(3)Ce4 tetrahedra, corners with five equivalent O(4)Ce4 tetrahedra, edges with two equivalent O(5)Ce6 octahedra, edges with two equivalent O(2)Ce5 square pyramids,  an edgeedge with one O(4)Ce4 tetrahedra, and edges with two equivalent O(3)Ce4 tetrahedra. In the third O site, O(3) is bonded to two equivalent Ce(1) and two equivalent Ce(3) atoms to form OCe4 tetrahedra that share corners with two equivalent O(5)Ce6 octahedra, corners with two equivalent O(2)Ce5 square pyramids, corners with two equivalent O(3)Ce4 tetrahedra, corners with two equivalent O(4)Ce4 tetrahedra,  an edgeedge with one O(5)Ce6 octahedra, edges with two equivalent O(2)Ce5 square pyramids, and  an edgeedge with one O(3)Ce4 tetrahedra. The corner-sharing octahedral tilt angles are 14°. In the fourth O site, O(4) is bonded to one Ce(3) and three equivalent Ce(2) atoms to form OCe4 tetrahedra that share  a cornercorner with one O(5)Ce6 octahedra, corners with five equivalent O(2)Ce5 square pyramids, corners with two equivalent O(3)Ce4 tetrahedra, corners with two equivalent O(4)Ce4 tetrahedra, edges with two equivalent O(5)Ce6 octahedra,  an edgeedge with one O(2)Ce5 square pyramid, and edges with two equivalent O(4)Ce4 tetrahedra. The corner-sharing octahedral tilt angles are 51°. In the fifth O site, O(5) is bonded to two equivalent Ce(2) and four equivalent Ce(3) atoms to form OCe6 octahedra that share corners with two equivalent O(4)Ce4 tetrahedra, corners with four equivalent O(3)Ce4 tetrahedra, edges with two equivalent O(5)Ce6 octahedra, edges with four equivalent O(2)Ce5 square pyramids, edges with two equivalent O(3)Ce4 tetrahedra, and edges with four equivalent O(4)Ce4 tetrahedra. is represented by the CIF file [CIF]
data_Ce2O3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.703
_cell_length_b   7.457
_cell_length_c   9.002
_cell_angle_alpha   99.770
_cell_angle_beta   90.000
_cell_angle_gamma   104.377
_symmetry_Int_Tables_number   1
_cell_volume   237.062
_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
  Ce  Ce0  1  0.366  0.732  0.510  1.0
  Ce  Ce1  1  0.310  0.620  0.861  1.0
  Ce  Ce2  1  0.634  0.268  0.490  1.0
  Ce  Ce3  1  0.033  0.065  0.813  1.0
  Ce  Ce4  1  0.967  0.935  0.187  1.0
  Ce  Ce5  1  0.690  0.380  0.139  1.0
  O  O6  1  0.797  0.594  0.373  1.0
  O  O7  1  0.127  0.254  0.285  1.0
  O  O8  1  0.527  0.054  0.657  1.0
  O  O9  1  0.203  0.406  0.627  1.0
  O  O10  1  0.176  0.351  0.973  1.0
  O  O11  1  0.824  0.649  0.027  1.0
  O  O12  1  0.473  0.946  0.343  1.0
  O  O13  1  0.500  0.000  0.000  1.0
  O  O14  1  0.873  0.746  0.715  1.0
[/CIF]
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