The structure described by Tb7O12 crystallizes in the trigonal R-3 space group. There are two inequivalent Tb sites. In the first Tb site, Tb(1) is bonded in a 7-coordinate geometry to three equivalent O(2) and four equivalent O(1) atoms. In the second Tb site, Tb(2) is bonded in a distorted octahedral geometry to six equivalent O(2) atoms. There are two inequivalent O sites. In the first O site, O(2) is bonded to one Tb(2) and three equivalent Tb(1) atoms to form a mixture of edge and corner-sharing OTb4 tetrahedra. In the second O site, O(1) is bonded to four equivalent Tb(1) atoms to form a mixture of edge and corner-sharing OTb4 tetrahedra. is represented by the CIF file [CIF]
data_Tb7O12
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.643
_cell_length_b   6.643
_cell_length_c   6.643
_cell_angle_alpha   99.503
_cell_angle_beta   99.503
_cell_angle_gamma   99.503
_symmetry_Int_Tables_number   1
_cell_volume   279.568
_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
  Tb  Tb0  1  0.698  0.392  0.862  1.0
  Tb  Tb1  1  0.862  0.698  0.392  1.0
  Tb  Tb2  1  0.392  0.862  0.698  1.0
  Tb  Tb3  1  0.302  0.608  0.138  1.0
  Tb  Tb4  1  0.138  0.302  0.608  1.0
  Tb  Tb5  1  0.608  0.138  0.302  1.0
  Tb  Tb6  1  0.000  0.000  0.000  1.0
  O  O7  1  0.436  0.179  0.579  1.0
  O  O8  1  0.579  0.436  0.179  1.0
  O  O9  1  0.179  0.579  0.436  1.0
  O  O10  1  0.564  0.821  0.421  1.0
  O  O11  1  0.421  0.564  0.821  1.0
  O  O12  1  0.821  0.421  0.564  1.0
  O  O13  1  0.063  0.326  0.936  1.0
  O  O14  1  0.674  0.064  0.937  1.0
  O  O15  1  0.064  0.937  0.674  1.0
  O  O16  1  0.937  0.674  0.064  1.0
  O  O17  1  0.326  0.936  0.063  1.0
  O  O18  1  0.936  0.063  0.326  1.0
[/CIF]
.
The structure described by Tb7O12 crystallizes in the trigonal R-3 space group. There are two inequivalent Tb sites. In the first Tb site, Tb(1) is bonded in a 7-coordinate geometry to three equivalent O(2) and four equivalent O(1) atoms. In the second Tb site, Tb(2) is bonded in a distorted octahedral geometry to six equivalent O(2) atoms. There are two inequivalent O sites. In the first O site, O(2) is bonded to one Tb(2) and three equivalent Tb(1) atoms to form a mixture of edge and corner-sharing OTb4 tetrahedra. In the second O site, O(1) is bonded to four equivalent Tb(1) atoms to form a mixture of edge and corner-sharing OTb4 tetrahedra. is represented by the CIF file [CIF]
data_Tb7O12
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.643
_cell_length_b   6.643
_cell_length_c   6.643
_cell_angle_alpha   99.503
_cell_angle_beta   99.503
_cell_angle_gamma   99.503
_symmetry_Int_Tables_number   1
_cell_volume   279.568
_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
  Tb  Tb0  1  0.698  0.392  0.862  1.0
  Tb  Tb1  1  0.862  0.698  0.392  1.0
  Tb  Tb2  1  0.392  0.862  0.698  1.0
  Tb  Tb3  1  0.302  0.608  0.138  1.0
  Tb  Tb4  1  0.138  0.302  0.608  1.0
  Tb  Tb5  1  0.608  0.138  0.302  1.0
  Tb  Tb6  1  0.000  0.000  0.000  1.0
  O  O7  1  0.436  0.179  0.579  1.0
  O  O8  1  0.579  0.436  0.179  1.0
  O  O9  1  0.179  0.579  0.436  1.0
  O  O10  1  0.564  0.821  0.421  1.0
  O  O11  1  0.421  0.564  0.821  1.0
  O  O12  1  0.821  0.421  0.564  1.0
  O  O13  1  0.063  0.326  0.936  1.0
  O  O14  1  0.674  0.064  0.937  1.0
  O  O15  1  0.064  0.937  0.674  1.0
  O  O16  1  0.937  0.674  0.064  1.0
  O  O17  1  0.326  0.936  0.063  1.0
  O  O18  1  0.936  0.063  0.326  1.0
[/CIF]
.