data_Tb3Co
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.97
_cell_length_b   5.97
_cell_length_c   5.97
_cell_angle_alpha   136.83
_cell_angle_beta   136.83
_cell_angle_gamma   62.7
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Tb3Co
_chemical_formula_sum   'Tb3 Co1'
_cell_volume   98.45
_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  0.0  0.0  0.1  1.0
  Tb  Tb2  1  0.0  0.2  0.55  1.0
  Tb  Tb3  1  0.2  0.0  0.55  1.0
  Co  Co0  1  0.0  0.0  0.0  1.0

data_Tb3Co
_symmetry_space_group_name_H-M   Cm
_cell_length_a   6.21
_cell_length_b   6.21
_cell_length_c   5.97
_cell_angle_alpha   90.0
_cell_angle_beta   121.35
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   Tb3Co
_chemical_formula_sum   'Tb6 Co2'
_cell_volume   196.89
_cell_formula_units_Z   2
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  'x, -y, z'
  3  'x+1/2, y+1/2, z'
  4  'x+1/2, -y+1/2, 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  4  0.05  0.4  0.65  1.0
  Tb  Tb1  2  0.4  0.5  0.9  1.0
  Co  Co2  2  0.0  0.0  0.0  1.0

Tb Tb Tb Co
Tb Tb Tb Co 0 3 o o o 1 2 o o o 
Tb3Co is BCT5 structured and crystallizes in the monoclinic Cm space group. The structure is zero-dimensional and consists of two terbium molecules and two TbCo clusters. In each TbCo cluster, Tb(1) is bonded in a single-bond geometry to one Co(1) atom. The Tb(1)-Co(1) bond length is 0.59 Å. Co(1) is bonded in a single-bond geometry to one Tb(1) atom.