The material structure described by NdTa3O9 crystallizes in the monoclinic C2/m space group. Nd(1) is bonded to one O(2), two equivalent O(1), two equivalent O(3), three equivalent O(7), and four equivalent O(6) atoms to form NdO12 cuboctahedra that share corners with three equivalent Nd(1)O12 cuboctahedra, faces with two equivalent Nd(1)O12 cuboctahedra, faces with two equivalent Ta(1)O6 octahedra, faces with three equivalent Ta(2)O6 octahedra, and faces with three equivalent Ta(3)O6 octahedra. There are three inequivalent Ta sites. In the first Ta site, Ta(1) is bonded to one O(2), one O(5), two equivalent O(1), and two equivalent O(3) atoms to form TaO6 octahedra that share  a cornercorner with one Ta(1)O6 octahedra, corners with two equivalent Ta(3)O6 octahedra, corners with three equivalent Ta(2)O6 octahedra, and faces with two equivalent Nd(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-14°. In the second Ta site, Ta(2) is bonded to one O(5), one O(7), two equivalent O(1), and two equivalent O(6) atoms to form TaO6 octahedra that share corners with three equivalent Ta(1)O6 octahedra, corners with three equivalent Ta(3)O6 octahedra, and faces with three equivalent Nd(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 2-17°. In the third Ta site, Ta(3) is bonded to one O(4), one O(7), two equivalent O(3), and two equivalent O(6) atoms to form TaO6 octahedra that share  a cornercorner with one Ta(3)O6 octahedra, corners with two equivalent Ta(1)O6 octahedra, corners with three equivalent Ta(2)O6 octahedra, and faces with three equivalent Nd(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-17°. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted T-shaped geometry to one Nd(1), one Ta(1), and one Ta(2) atom. In the second O site, O(2) is bonded in a distorted linear geometry to two equivalent Nd(1) and two equivalent Ta(1) atoms. In the third O site, O(3) is bonded in a distorted T-shaped geometry to one Nd(1), one Ta(1), and one Ta(3) atom. In the fourth O site, O(4) is bonded in a linear geometry to two equivalent Ta(3) atoms. In the fifth O site, O(5) is bonded in a linear geometry to one Ta(1) and one Ta(2) atom. In the sixth O site, O(6) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Nd(1), one Ta(2), and one Ta(3) atom. In the seventh O site, O(7) is bonded to three equivalent Nd(1), one Ta(2), and one Ta(3) atom to form a mixture of distorted corner and edge-sharing ONd3Ta2 square pyramids. is represented by the CIF file [CIF]
data_NdTa3O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.820
_cell_length_b   8.820
_cell_length_c   9.716
_cell_angle_alpha   57.032
_cell_angle_beta   57.032
_cell_angle_gamma   36.931
_symmetry_Int_Tables_number   1
_cell_volume   371.959
_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
  Nd  Nd0  1  0.332  0.332  0.000  1.0
  Nd  Nd1  1  0.668  0.668  1.000  1.0
  Ta  Ta2  1  0.584  0.584  0.748  1.0
  Ta  Ta3  1  0.750  0.750  0.261  1.0
  Ta  Ta4  1  0.077  0.077  0.258  1.0
  Ta  Ta5  1  0.416  0.416  0.252  1.0
  Ta  Ta6  1  0.250  0.250  0.739  1.0
  Ta  Ta7  1  0.923  0.923  0.742  1.0
  O  O8  1  0.574  0.096  0.231  1.0
  O  O9  1  0.500  0.500  0.000  1.0
  O  O10  1  0.096  0.574  0.231  1.0
  O  O11  1  0.728  0.251  0.769  1.0
  O  O12  1  0.000  0.000  0.500  1.0
  O  O13  1  0.666  0.666  0.502  1.0
  O  O14  1  0.926  0.426  0.222  1.0
  O  O15  1  0.826  0.826  0.000  1.0
  O  O16  1  0.174  0.174  1.000  1.0
  O  O17  1  0.574  0.074  0.778  1.0
  O  O18  1  0.749  0.272  0.231  1.0
  O  O19  1  0.251  0.728  0.769  1.0
  O  O20  1  0.426  0.926  0.222  1.0
  O  O21  1  0.334  0.334  0.498  1.0
  O  O22  1  0.272  0.749  0.231  1.0
  O  O23  1  0.074  0.574  0.778  1.0
  O  O24  1  0.904  0.426  0.769  1.0
  O  O25  1  0.426  0.904  0.769  1.0
[/CIF]
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The material structure described by NdTa3O9 crystallizes in the monoclinic C2/m space group. Nd(1) is bonded to one O(2), two equivalent O(1), two equivalent O(3), three equivalent O(7), and four equivalent O(6) atoms to form NdO12 cuboctahedra that share corners with three equivalent Nd(1)O12 cuboctahedra, faces with two equivalent Nd(1)O12 cuboctahedra, faces with two equivalent Ta(1)O6 octahedra, faces with three equivalent Ta(2)O6 octahedra, and faces with three equivalent Ta(3)O6 octahedra. There are three inequivalent Ta sites. In the first Ta site, Ta(1) is bonded to one O(2), one O(5), two equivalent O(1), and two equivalent O(3) atoms to form TaO6 octahedra that share  a cornercorner with one Ta(1)O6 octahedra, corners with two equivalent Ta(3)O6 octahedra, corners with three equivalent Ta(2)O6 octahedra, and faces with two equivalent Nd(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-14°. In the second Ta site, Ta(2) is bonded to one O(5), one O(7), two equivalent O(1), and two equivalent O(6) atoms to form TaO6 octahedra that share corners with three equivalent Ta(1)O6 octahedra, corners with three equivalent Ta(3)O6 octahedra, and faces with three equivalent Nd(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 2-17°. In the third Ta site, Ta(3) is bonded to one O(4), one O(7), two equivalent O(3), and two equivalent O(6) atoms to form TaO6 octahedra that share  a cornercorner with one Ta(3)O6 octahedra, corners with two equivalent Ta(1)O6 octahedra, corners with three equivalent Ta(2)O6 octahedra, and faces with three equivalent Nd(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-17°. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted T-shaped geometry to one Nd(1), one Ta(1), and one Ta(2) atom. In the second O site, O(2) is bonded in a distorted linear geometry to two equivalent Nd(1) and two equivalent Ta(1) atoms. In the third O site, O(3) is bonded in a distorted T-shaped geometry to one Nd(1), one Ta(1), and one Ta(3) atom. In the fourth O site, O(4) is bonded in a linear geometry to two equivalent Ta(3) atoms. In the fifth O site, O(5) is bonded in a linear geometry to one Ta(1) and one Ta(2) atom. In the sixth O site, O(6) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Nd(1), one Ta(2), and one Ta(3) atom. In the seventh O site, O(7) is bonded to three equivalent Nd(1), one Ta(2), and one Ta(3) atom to form a mixture of distorted corner and edge-sharing ONd3Ta2 square pyramids. is represented by the CIF file [CIF]
data_NdTa3O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.820
_cell_length_b   8.820
_cell_length_c   9.716
_cell_angle_alpha   57.032
_cell_angle_beta   57.032
_cell_angle_gamma   36.931
_symmetry_Int_Tables_number   1
_cell_volume   371.959
_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
  Nd  Nd0  1  0.332  0.332  0.000  1.0
  Nd  Nd1  1  0.668  0.668  1.000  1.0
  Ta  Ta2  1  0.584  0.584  0.748  1.0
  Ta  Ta3  1  0.750  0.750  0.261  1.0
  Ta  Ta4  1  0.077  0.077  0.258  1.0
  Ta  Ta5  1  0.416  0.416  0.252  1.0
  Ta  Ta6  1  0.250  0.250  0.739  1.0
  Ta  Ta7  1  0.923  0.923  0.742  1.0
  O  O8  1  0.574  0.096  0.231  1.0
  O  O9  1  0.500  0.500  0.000  1.0
  O  O10  1  0.096  0.574  0.231  1.0
  O  O11  1  0.728  0.251  0.769  1.0
  O  O12  1  0.000  0.000  0.500  1.0
  O  O13  1  0.666  0.666  0.502  1.0
  O  O14  1  0.926  0.426  0.222  1.0
  O  O15  1  0.826  0.826  0.000  1.0
  O  O16  1  0.174  0.174  1.000  1.0
  O  O17  1  0.574  0.074  0.778  1.0
  O  O18  1  0.749  0.272  0.231  1.0
  O  O19  1  0.251  0.728  0.769  1.0
  O  O20  1  0.426  0.926  0.222  1.0
  O  O21  1  0.334  0.334  0.498  1.0
  O  O22  1  0.272  0.749  0.231  1.0
  O  O23  1  0.074  0.574  0.778  1.0
  O  O24  1  0.904  0.426  0.769  1.0
  O  O25  1  0.426  0.904  0.769  1.0
[/CIF]
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