data_Ba2HfNb
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   12.01
_cell_length_b   12.01
_cell_length_c   12.01
_cell_angle_alpha   17.19
_cell_angle_beta   17.19
_cell_angle_gamma   17.19
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Ba2HfNb
_chemical_formula_sum   'Ba2 Hf1 Nb1'
_cell_volume   131.85
_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
  Ba  Ba0  1  0.0  0.0  0.59  1.0
  Ba  Ba1  1  0.0  0.0  0.42  1.0
  Hf  Hf2  1  0.0  0.0  0.17  1.0
  Nb  Nb3  1  0.0  0.0  0.03  1.0

data_Ba2HfNb
_symmetry_space_group_name_H-M   Cm
_cell_length_a   6.21
_cell_length_b   3.59
_cell_length_c   12.01
_cell_angle_alpha   90.0
_cell_angle_beta   99.94
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   Ba2HfNb
_chemical_formula_sum   'Ba4 Hf2 Nb2'
_cell_volume   263.7
_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
  Ba  Ba0  2  0.0  0.0  0.41  1.0
  Ba  Ba1  2  0.0  0.0  0.58  1.0
  Hf  Hf2  2  0.0  0.0  0.83  1.0
  Nb  Nb3  2  0.0  0.0  0.97  1.0

Ba Ba Hf Nb
Ba Ba Hf Nb 0 1 o o o 2 3 o o o 
Ba2HfNb crystallizes in the monoclinic Cm space group. The structure is zero-dimensional and consists of two Ba2HfNb clusters. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a single-bond geometry to one Ba(2) atom. The Ba(1)-Ba(2) bond length is 1.97 Å. In the second Ba site, Ba(2) is bonded in a linear geometry to one Ba(1) and one Hf(1) atom. The Ba(2)-Hf(1) bond length is 3.07 Å. Hf(1) is bonded in a distorted single-bond geometry to one Ba(2) and one Nb(1) atom. The Hf(1)-Nb(1) bond length is 1.63 Å. Nb(1) is bonded in a single-bond geometry to one Hf(1) atom.