data_Rb2TbNb
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.19
_cell_length_b   6.19
_cell_length_c   6.19
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Rb2TbNb
_chemical_formula_sum   'Rb2 Tb1 Nb1'
_cell_volume   167.58
_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
  Rb  Rb1  1  0.56  0.56  0.56  1.0
  Rb  Rb2  1  0.19  0.19  0.19  1.0
  Tb  Tb3  1  0.38  0.38  0.38  1.0
  Nb  Nb0  1  0.0  0.0  0.0  1.0

data_Rb2TbNb
_symmetry_space_group_name_H-M   R3m
_cell_length_a   6.19
_cell_length_b   6.19
_cell_length_c   15.16
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   Rb2TbNb
_chemical_formula_sum   'Rb6 Tb3 Nb3'
_cell_volume   502.75
_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
  Rb  Rb0  3  0.0  0.0  0.44  1.0
  Rb  Rb1  3  0.0  0.0  0.81  1.0
  Tb  Tb2  3  0.0  0.0  0.62  1.0
  Nb  Nb3  3  0.0  0.0  -0.0  1.0

Rb Rb Tb Nb
Rb2TbNb crystallizes in the trigonal R3m space group. There are two inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a 1-coordinate geometry to one Tb(1) atom. The Rb(1)-Tb(1) bond length is 2.85 Å. In the second Rb site, Rb(2) is bonded in a linear geometry to one Tb(1) and one Nb(1) atom. The Rb(2)-Tb(1) bond length is 2.85 Å. The Rb(2)-Nb(1) bond length is 2.85 Å. Tb(1) is bonded in a 5-coordinate geometry to one Rb(1), one Rb(2), and three equivalent Nb(1) atoms. All Tb(1)-Nb(1) bond lengths are 3.63 Å. Nb(1) is bonded in a distorted single-bond geometry to one Rb(2) and three equivalent Tb(1) atoms.