The material structure described by CeTa7O19 crystallizes in the hexagonal P-6c2 space group. Ce(1) is bonded in a 8-coordinate geometry to two equivalent O(4) and six equivalent O(5) atoms. There are two inequivalent Ta sites. In the first Ta site, Ta(1) is bonded in a 7-coordinate geometry to one O(1), one O(3), one O(4), one O(5), and three equivalent O(2) atoms. In the second Ta site, Ta(2) is bonded in an octahedral geometry to six equivalent O(5) atoms. There are five inequivalent O sites. In the first O site, O(3) is bonded in a trigonal planar geometry to three equivalent Ta(1) atoms. In the second O site, O(4) is bonded to one Ce(1) and three equivalent Ta(1) atoms to form distorted corner-sharing OCeTa3 tetrahedra. In the third O site, O(5) is bonded in a distorted trigonal non-coplanar geometry to one Ce(1), one Ta(1), and one Ta(2) atom. In the fourth O site, O(1) is bonded in a bent 150 degrees geometry to two equivalent Ta(1) atoms. In the fifth O site, O(2) is bonded in a distorted bent 150 degrees geometry to three equivalent Ta(1) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_CeTa7O19
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.294
_cell_length_b   6.294
_cell_length_c   20.184
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   692.511
_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  0.000  0.000  0.000  1.0
  Ce  Ce1  1  0.000  0.000  0.500  1.0
  Ta  Ta2  1  0.974  0.309  0.844  1.0
  Ta  Ta3  1  0.335  0.026  0.844  1.0
  Ta  Ta4  1  0.974  0.309  0.656  1.0
  Ta  Ta5  1  0.335  0.309  0.344  1.0
  Ta  Ta6  1  0.691  0.665  0.844  1.0
  Ta  Ta7  1  0.335  0.026  0.656  1.0
  Ta  Ta8  1  0.691  0.026  0.344  1.0
  Ta  Ta9  1  0.335  0.309  0.156  1.0
  Ta  Ta10  1  0.691  0.665  0.656  1.0
  Ta  Ta11  1  0.691  0.026  0.156  1.0
  Ta  Ta12  1  0.974  0.665  0.344  1.0
  Ta  Ta13  1  0.974  0.665  0.156  1.0
  Ta  Ta14  1  0.667  0.333  0.000  1.0
  Ta  Ta15  1  0.667  0.333  0.500  1.0
  O  O16  1  0.957  0.253  0.750  1.0
  O  O17  1  0.296  0.043  0.750  1.0
  O  O18  1  0.296  0.253  0.250  1.0
  O  O19  1  0.747  0.704  0.750  1.0
  O  O20  1  0.747  0.043  0.250  1.0
  O  O21  1  0.957  0.704  0.250  1.0
  O  O22  1  0.579  0.912  0.847  1.0
  O  O23  1  0.333  0.421  0.847  1.0
  O  O24  1  0.579  0.912  0.653  1.0
  O  O25  1  0.333  0.912  0.347  1.0
  O  O26  1  0.088  0.667  0.847  1.0
  O  O27  1  0.333  0.421  0.653  1.0
  O  O28  1  0.088  0.421  0.347  1.0
  O  O29  1  0.333  0.912  0.153  1.0
  O  O30  1  0.088  0.667  0.653  1.0
  O  O31  1  0.088  0.421  0.153  1.0
  O  O32  1  0.579  0.667  0.347  1.0
  O  O33  1  0.579  0.667  0.153  1.0
  O  O34  1  0.667  0.333  0.835  1.0
  O  O35  1  0.667  0.333  0.665  1.0
  O  O36  1  0.667  0.333  0.335  1.0
  O  O37  1  0.667  0.333  0.165  1.0
  O  O38  1  0.000  0.000  0.867  1.0
  O  O39  1  0.000  0.000  0.633  1.0
  O  O40  1  0.000  0.000  0.367  1.0
  O  O41  1  0.000  0.000  0.133  1.0
  O  O42  1  0.905  0.289  0.944  1.0
  O  O43  1  0.384  0.095  0.944  1.0
  O  O44  1  0.905  0.289  0.556  1.0
  O  O45  1  0.384  0.289  0.444  1.0
  O  O46  1  0.711  0.616  0.944  1.0
  O  O47  1  0.384  0.095  0.556  1.0
  O  O48  1  0.711  0.095  0.444  1.0
  O  O49  1  0.384  0.289  0.056  1.0
  O  O50  1  0.711  0.616  0.556  1.0
  O  O51  1  0.711  0.095  0.056  1.0
  O  O52  1  0.905  0.616  0.444  1.0
  O  O53  1  0.905  0.616  0.056  1.0
[/CIF]
.
The material structure described by CeTa7O19 crystallizes in the hexagonal P-6c2 space group. Ce(1) is bonded in a 8-coordinate geometry to two equivalent O(4) and six equivalent O(5) atoms. There are two inequivalent Ta sites. In the first Ta site, Ta(1) is bonded in a 7-coordinate geometry to one O(1), one O(3), one O(4), one O(5), and three equivalent O(2) atoms. In the second Ta site, Ta(2) is bonded in an octahedral geometry to six equivalent O(5) atoms. There are five inequivalent O sites. In the first O site, O(3) is bonded in a trigonal planar geometry to three equivalent Ta(1) atoms. In the second O site, O(4) is bonded to one Ce(1) and three equivalent Ta(1) atoms to form distorted corner-sharing OCeTa3 tetrahedra. In the third O site, O(5) is bonded in a distorted trigonal non-coplanar geometry to one Ce(1), one Ta(1), and one Ta(2) atom. In the fourth O site, O(1) is bonded in a bent 150 degrees geometry to two equivalent Ta(1) atoms. In the fifth O site, O(2) is bonded in a distorted bent 150 degrees geometry to three equivalent Ta(1) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_CeTa7O19
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.294
_cell_length_b   6.294
_cell_length_c   20.184
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   692.511
_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  0.000  0.000  0.000  1.0
  Ce  Ce1  1  0.000  0.000  0.500  1.0
  Ta  Ta2  1  0.974  0.309  0.844  1.0
  Ta  Ta3  1  0.335  0.026  0.844  1.0
  Ta  Ta4  1  0.974  0.309  0.656  1.0
  Ta  Ta5  1  0.335  0.309  0.344  1.0
  Ta  Ta6  1  0.691  0.665  0.844  1.0
  Ta  Ta7  1  0.335  0.026  0.656  1.0
  Ta  Ta8  1  0.691  0.026  0.344  1.0
  Ta  Ta9  1  0.335  0.309  0.156  1.0
  Ta  Ta10  1  0.691  0.665  0.656  1.0
  Ta  Ta11  1  0.691  0.026  0.156  1.0
  Ta  Ta12  1  0.974  0.665  0.344  1.0
  Ta  Ta13  1  0.974  0.665  0.156  1.0
  Ta  Ta14  1  0.667  0.333  0.000  1.0
  Ta  Ta15  1  0.667  0.333  0.500  1.0
  O  O16  1  0.957  0.253  0.750  1.0
  O  O17  1  0.296  0.043  0.750  1.0
  O  O18  1  0.296  0.253  0.250  1.0
  O  O19  1  0.747  0.704  0.750  1.0
  O  O20  1  0.747  0.043  0.250  1.0
  O  O21  1  0.957  0.704  0.250  1.0
  O  O22  1  0.579  0.912  0.847  1.0
  O  O23  1  0.333  0.421  0.847  1.0
  O  O24  1  0.579  0.912  0.653  1.0
  O  O25  1  0.333  0.912  0.347  1.0
  O  O26  1  0.088  0.667  0.847  1.0
  O  O27  1  0.333  0.421  0.653  1.0
  O  O28  1  0.088  0.421  0.347  1.0
  O  O29  1  0.333  0.912  0.153  1.0
  O  O30  1  0.088  0.667  0.653  1.0
  O  O31  1  0.088  0.421  0.153  1.0
  O  O32  1  0.579  0.667  0.347  1.0
  O  O33  1  0.579  0.667  0.153  1.0
  O  O34  1  0.667  0.333  0.835  1.0
  O  O35  1  0.667  0.333  0.665  1.0
  O  O36  1  0.667  0.333  0.335  1.0
  O  O37  1  0.667  0.333  0.165  1.0
  O  O38  1  0.000  0.000  0.867  1.0
  O  O39  1  0.000  0.000  0.633  1.0
  O  O40  1  0.000  0.000  0.367  1.0
  O  O41  1  0.000  0.000  0.133  1.0
  O  O42  1  0.905  0.289  0.944  1.0
  O  O43  1  0.384  0.095  0.944  1.0
  O  O44  1  0.905  0.289  0.556  1.0
  O  O45  1  0.384  0.289  0.444  1.0
  O  O46  1  0.711  0.616  0.944  1.0
  O  O47  1  0.384  0.095  0.556  1.0
  O  O48  1  0.711  0.095  0.444  1.0
  O  O49  1  0.384  0.289  0.056  1.0
  O  O50  1  0.711  0.616  0.556  1.0
  O  O51  1  0.711  0.095  0.056  1.0
  O  O52  1  0.905  0.616  0.444  1.0
  O  O53  1  0.905  0.616  0.056  1.0
[/CIF]
.