data_Tb3I
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.9
_cell_length_b   4.9
_cell_length_c   4.9
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Tb3I
_chemical_formula_sum   'Tb3 I1'
_cell_volume   117.68
_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  Tb1  1  0.45  0.45  0.0  1.0
  Tb  Tb2  1  0.45  0.0  0.45  1.0
  Tb  Tb3  1  0.0  0.45  0.45  1.0
  I  I0  1  0.0  0.0  0.0  1.0

data_Tb3I
_symmetry_space_group_name_H-M   R3m
_cell_length_a   6.93
_cell_length_b   6.93
_cell_length_c   8.49
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   Tb3I
_chemical_formula_sum   'Tb9 I3'
_cell_volume   353.04
_cell_formula_units_Z   3
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  '-y, x-y, z'
  3  '-x+y, -x, z'
  4  '-y, -x, z'
  5  '-x+y, y, z'
  6  'x, x-y, z'
  7  'x+1/3, y+2/3, z+2/3'
  8  '-y+1/3, x-y+2/3, z+2/3'
  9  '-x+y+1/3, -x+2/3, z+2/3'
  10  '-y+1/3, -x+2/3, z+2/3'
  11  '-x+y+1/3, y+2/3, z+2/3'
  12  'x+1/3, x-y+2/3, z+2/3'
  13  'x+2/3, y+1/3, z+1/3'
  14  '-y+2/3, x-y+1/3, z+1/3'
  15  '-x+y+2/3, -x+1/3, z+1/3'
  16  '-y+2/3, -x+1/3, z+1/3'
  17  '-x+y+2/3, y+1/3, z+1/3'
  18  'x+2/3, x-y+1/3, z+1/3'
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  9  0.03  0.52  0.97  1.0
  I  I1  3  0.0  0.0  0.0  1.0

Tb Tb Tb I
Tb3I is Uranium Silicide structured and crystallizes in the trigonal R3m space group. Tb(1) is bonded in a 12-coordinate geometry to eight equivalent Tb(1) and four equivalent I(1) atoms. There are a spread of Tb(1)-Tb(1) bond distances ranging from 3.12-3.81 Å. There are a spread of Tb(1)-I(1) bond distances ranging from 3.12-3.81 Å. I(1) is bonded to twelve equivalent Tb(1) atoms to form a mixture of face and corner-sharing ITb12 cuboctahedra.