The material described by Tb2Nb2O7 crystallizes in the cubic Fd-3m space group. Tb(1) is bonded in a body-centered cubic geometry to two equivalent O(2) and six equivalent O(1) atoms. Nb(1) is bonded to six equivalent O(1) atoms to form distorted corner-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles are 56°. There are two inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Tb(1) and two equivalent Nb(1) atoms to form OTb2Nb2 tetrahedra that share corners with two equivalent O(2)Tb4 tetrahedra, corners with twelve equivalent O(1)Tb2Nb2 tetrahedra,  an edgeedge with one O(2)Tb4 tetrahedra, and edges with four equivalent O(1)Tb2Nb2 tetrahedra. In the second O site, O(2) is bonded to four equivalent Tb(1) atoms to form OTb4 tetrahedra that share corners with four equivalent O(2)Tb4 tetrahedra, corners with twelve equivalent O(1)Tb2Nb2 tetrahedra, and edges with six equivalent O(1)Tb2Nb2 tetrahedra. is represented by the CIF card [CIF]
data_Tb2Nb2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.361
_cell_length_b   7.361
_cell_length_c   7.361
_cell_angle_alpha   60.000
_cell_angle_beta   60.000
_cell_angle_gamma   60.000
_symmetry_Int_Tables_number   1
_cell_volume   282.065
_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
  Tb  Tb0  1  0.125  0.625  0.125  1.0
  Tb  Tb1  1  0.125  0.125  0.625  1.0
  Tb  Tb2  1  0.625  0.125  0.125  1.0
  Tb  Tb3  1  0.125  0.125  0.125  1.0
  Nb  Nb4  1  0.625  0.625  0.625  1.0
  Nb  Nb5  1  0.125  0.625  0.625  1.0
  Nb  Nb6  1  0.625  0.125  0.625  1.0
  Nb  Nb7  1  0.625  0.625  0.125  1.0
  O  O8  1  0.281  0.719  0.719  1.0
  O  O9  1  0.531  0.969  0.969  1.0
  O  O10  1  0.719  0.281  0.719  1.0
  O  O11  1  0.719  0.719  0.281  1.0
  O  O12  1  0.281  0.281  0.719  1.0
  O  O13  1  0.000  0.000  0.000  1.0
  O  O14  1  0.281  0.719  0.281  1.0
  O  O15  1  0.969  0.531  0.969  1.0
  O  O16  1  0.969  0.969  0.531  1.0
  O  O17  1  0.250  0.250  0.250  1.0
  O  O18  1  0.531  0.969  0.531  1.0
  O  O19  1  0.531  0.531  0.969  1.0
  O  O20  1  0.719  0.281  0.281  1.0
  O  O21  1  0.969  0.531  0.531  1.0
[/CIF]
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The material described by Tb2Nb2O7 crystallizes in the cubic Fd-3m space group. Tb(1) is bonded in a body-centered cubic geometry to two equivalent O(2) and six equivalent O(1) atoms. Nb(1) is bonded to six equivalent O(1) atoms to form distorted corner-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles are 56°. There are two inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Tb(1) and two equivalent Nb(1) atoms to form OTb2Nb2 tetrahedra that share corners with two equivalent O(2)Tb4 tetrahedra, corners with twelve equivalent O(1)Tb2Nb2 tetrahedra,  an edgeedge with one O(2)Tb4 tetrahedra, and edges with four equivalent O(1)Tb2Nb2 tetrahedra. In the second O site, O(2) is bonded to four equivalent Tb(1) atoms to form OTb4 tetrahedra that share corners with four equivalent O(2)Tb4 tetrahedra, corners with twelve equivalent O(1)Tb2Nb2 tetrahedra, and edges with six equivalent O(1)Tb2Nb2 tetrahedra. is represented by the CIF card [CIF]
data_Tb2Nb2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.361
_cell_length_b   7.361
_cell_length_c   7.361
_cell_angle_alpha   60.000
_cell_angle_beta   60.000
_cell_angle_gamma   60.000
_symmetry_Int_Tables_number   1
_cell_volume   282.065
_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
  Tb  Tb0  1  0.125  0.625  0.125  1.0
  Tb  Tb1  1  0.125  0.125  0.625  1.0
  Tb  Tb2  1  0.625  0.125  0.125  1.0
  Tb  Tb3  1  0.125  0.125  0.125  1.0
  Nb  Nb4  1  0.625  0.625  0.625  1.0
  Nb  Nb5  1  0.125  0.625  0.625  1.0
  Nb  Nb6  1  0.625  0.125  0.625  1.0
  Nb  Nb7  1  0.625  0.625  0.125  1.0
  O  O8  1  0.281  0.719  0.719  1.0
  O  O9  1  0.531  0.969  0.969  1.0
  O  O10  1  0.719  0.281  0.719  1.0
  O  O11  1  0.719  0.719  0.281  1.0
  O  O12  1  0.281  0.281  0.719  1.0
  O  O13  1  0.000  0.000  0.000  1.0
  O  O14  1  0.281  0.719  0.281  1.0
  O  O15  1  0.969  0.531  0.969  1.0
  O  O16  1  0.969  0.969  0.531  1.0
  O  O17  1  0.250  0.250  0.250  1.0
  O  O18  1  0.531  0.969  0.531  1.0
  O  O19  1  0.531  0.531  0.969  1.0
  O  O20  1  0.719  0.281  0.281  1.0
  O  O21  1  0.969  0.531  0.531  1.0
[/CIF]
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