The structure described by Ce2Ta2O9 crystallizes in the monoclinic P2_1/c space group. Ce(1) is bonded in a 9-coordinate geometry to one O(4), two equivalent O(1), three equivalent O(2), and three equivalent O(5) atoms. Ta(1) is bonded to one O(3), one O(5), two equivalent O(1), and two equivalent O(4) atoms to form a mixture of edge and corner-sharing TaO6 octahedra. The corner-sharing octahedral tilt angles range from 0-19°. There are five inequivalent O sites. In the first O site, O(1) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Ce(1) and two equivalent Ta(1) atoms. In the second O site, O(2) is bonded in a trigonal non-coplanar geometry to three equivalent Ce(1) atoms. In the third O site, O(3) is bonded in a linear geometry to two equivalent Ta(1) atoms. In the fourth O site, O(4) is bonded in a distorted T-shaped geometry to one Ce(1) and two equivalent Ta(1) atoms. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to three equivalent Ce(1) and one Ta(1) atom. is represented by the CIF card [CIF]
data_Ce2Ta2O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.864
_cell_length_b   6.538
_cell_length_c   15.637
_cell_angle_alpha   65.760
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   360.241
_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
  Ce  Ce0  1  0.008  0.302  0.716  1.0
  Ce  Ce1  1  0.992  0.698  0.284  1.0
  Ce  Ce2  1  0.508  0.698  0.784  1.0
  Ce  Ce3  1  0.492  0.302  0.216  1.0
  Ta  Ta4  1  0.004  0.763  0.959  1.0
  Ta  Ta5  1  0.996  0.237  0.041  1.0
  Ta  Ta6  1  0.504  0.237  0.541  1.0
  Ta  Ta7  1  0.496  0.763  0.459  1.0
  O  O8  1  0.998  0.490  0.916  1.0
  O  O9  1  0.002  0.510  0.084  1.0
  O  O10  1  0.498  0.510  0.584  1.0
  O  O11  1  0.502  0.490  0.416  1.0
  O  O12  1  0.505  0.348  0.782  1.0
  O  O13  1  0.495  0.652  0.218  1.0
  O  O14  1  0.005  0.652  0.718  1.0
  O  O15  1  0.995  0.348  0.282  1.0
  O  O16  1  0.000  0.000  0.000  1.0
  O  O17  1  0.500  0.000  0.500  1.0
  O  O18  1  0.501  0.748  0.942  1.0
  O  O19  1  0.499  0.252  0.058  1.0
  O  O20  1  0.001  0.252  0.558  1.0
  O  O21  1  0.999  0.748  0.442  1.0
  O  O22  1  0.002  0.937  0.819  1.0
  O  O23  1  0.998  0.063  0.181  1.0
  O  O24  1  0.502  0.063  0.681  1.0
  O  O25  1  0.498  0.937  0.319  1.0
[/CIF]
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The structure described by Ce2Ta2O9 crystallizes in the monoclinic P2_1/c space group. Ce(1) is bonded in a 9-coordinate geometry to one O(4), two equivalent O(1), three equivalent O(2), and three equivalent O(5) atoms. Ta(1) is bonded to one O(3), one O(5), two equivalent O(1), and two equivalent O(4) atoms to form a mixture of edge and corner-sharing TaO6 octahedra. The corner-sharing octahedral tilt angles range from 0-19°. There are five inequivalent O sites. In the first O site, O(1) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Ce(1) and two equivalent Ta(1) atoms. In the second O site, O(2) is bonded in a trigonal non-coplanar geometry to three equivalent Ce(1) atoms. In the third O site, O(3) is bonded in a linear geometry to two equivalent Ta(1) atoms. In the fourth O site, O(4) is bonded in a distorted T-shaped geometry to one Ce(1) and two equivalent Ta(1) atoms. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to three equivalent Ce(1) and one Ta(1) atom. is represented by the CIF card [CIF]
data_Ce2Ta2O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.864
_cell_length_b   6.538
_cell_length_c   15.637
_cell_angle_alpha   65.760
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   360.241
_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
  Ce  Ce0  1  0.008  0.302  0.716  1.0
  Ce  Ce1  1  0.992  0.698  0.284  1.0
  Ce  Ce2  1  0.508  0.698  0.784  1.0
  Ce  Ce3  1  0.492  0.302  0.216  1.0
  Ta  Ta4  1  0.004  0.763  0.959  1.0
  Ta  Ta5  1  0.996  0.237  0.041  1.0
  Ta  Ta6  1  0.504  0.237  0.541  1.0
  Ta  Ta7  1  0.496  0.763  0.459  1.0
  O  O8  1  0.998  0.490  0.916  1.0
  O  O9  1  0.002  0.510  0.084  1.0
  O  O10  1  0.498  0.510  0.584  1.0
  O  O11  1  0.502  0.490  0.416  1.0
  O  O12  1  0.505  0.348  0.782  1.0
  O  O13  1  0.495  0.652  0.218  1.0
  O  O14  1  0.005  0.652  0.718  1.0
  O  O15  1  0.995  0.348  0.282  1.0
  O  O16  1  0.000  0.000  0.000  1.0
  O  O17  1  0.500  0.000  0.500  1.0
  O  O18  1  0.501  0.748  0.942  1.0
  O  O19  1  0.499  0.252  0.058  1.0
  O  O20  1  0.001  0.252  0.558  1.0
  O  O21  1  0.999  0.748  0.442  1.0
  O  O22  1  0.002  0.937  0.819  1.0
  O  O23  1  0.998  0.063  0.181  1.0
  O  O24  1  0.502  0.063  0.681  1.0
  O  O25  1  0.498  0.937  0.319  1.0
[/CIF]
.