The material described by Nd2Ta2O9 crystallizes in the monoclinic C2/m space group. Nd(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 distorted corner and edge-sharing TaO6 octahedra. The corner-sharing octahedral tilt angles range from 0-14°. There are five inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Nd(1) and two equivalent Ta(1) atoms to form a mixture of distorted corner and edge-sharing ONd2Ta2 trigonal pyramids. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to three equivalent Nd(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 Nd(1) and two equivalent Ta(1) atoms. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to three equivalent Nd(1) and one Ta(1) atom. is represented by the CIF card [CIF]
data_Nd2Ta2O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.033
_cell_length_b   8.033
_cell_length_c   6.721
_cell_angle_alpha   68.342
_cell_angle_beta   68.342
_cell_angle_gamma   28.068
_symmetry_Int_Tables_number   1
_cell_volume   188.735
_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
  Nd  Nd0  1  0.695  0.695  0.314  1.0
  Nd  Nd1  1  0.305  0.305  0.686  1.0
  Ta  Ta2  1  0.961  0.961  0.306  1.0
  Ta  Ta3  1  0.039  0.039  0.694  1.0
  O  O4  1  0.919  0.919  0.659  1.0
  O  O5  1  0.081  0.081  0.341  1.0
  O  O6  1  0.281  0.281  0.061  1.0
  O  O7  1  0.719  0.719  0.939  1.0
  O  O8  1  0.000  0.000  0.000  1.0
  O  O9  1  0.452  0.452  0.342  1.0
  O  O10  1  0.548  0.548  0.658  1.0
  O  O11  1  0.824  0.824  0.420  1.0
  O  O12  1  0.176  0.176  0.580  1.0
[/CIF]
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The material described by Nd2Ta2O9 crystallizes in the monoclinic C2/m space group. Nd(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 distorted corner and edge-sharing TaO6 octahedra. The corner-sharing octahedral tilt angles range from 0-14°. There are five inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Nd(1) and two equivalent Ta(1) atoms to form a mixture of distorted corner and edge-sharing ONd2Ta2 trigonal pyramids. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to three equivalent Nd(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 Nd(1) and two equivalent Ta(1) atoms. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to three equivalent Nd(1) and one Ta(1) atom. is represented by the CIF card [CIF]
data_Nd2Ta2O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.033
_cell_length_b   8.033
_cell_length_c   6.721
_cell_angle_alpha   68.342
_cell_angle_beta   68.342
_cell_angle_gamma   28.068
_symmetry_Int_Tables_number   1
_cell_volume   188.735
_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
  Nd  Nd0  1  0.695  0.695  0.314  1.0
  Nd  Nd1  1  0.305  0.305  0.686  1.0
  Ta  Ta2  1  0.961  0.961  0.306  1.0
  Ta  Ta3  1  0.039  0.039  0.694  1.0
  O  O4  1  0.919  0.919  0.659  1.0
  O  O5  1  0.081  0.081  0.341  1.0
  O  O6  1  0.281  0.281  0.061  1.0
  O  O7  1  0.719  0.719  0.939  1.0
  O  O8  1  0.000  0.000  0.000  1.0
  O  O9  1  0.452  0.452  0.342  1.0
  O  O10  1  0.548  0.548  0.658  1.0
  O  O11  1  0.824  0.824  0.420  1.0
  O  O12  1  0.176  0.176  0.580  1.0
[/CIF]
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