data_Ba2NbHg
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.92
_cell_length_b   5.92
_cell_length_c   5.92
_cell_angle_alpha   125.34
_cell_angle_beta   125.34
_cell_angle_gamma   80.98
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Ba2NbHg
_chemical_formula_sum   'Ba2 Nb1 Hg1'
_cell_volume   133.29
_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  0.72  0.0  0.25  1.0
  Ba  Ba1  1  0.0  0.0  0.5  1.0
  Nb  Nb3  1  0.0  0.0  0.0  1.0
  Hg  Hg2  1  0.0  0.72  0.25  1.0

data_Ba2NbHg
_symmetry_space_group_name_H-M   P1
_cell_length_a   5.44
_cell_length_b   5.44
_cell_length_c   5.92
_cell_angle_alpha   117.33
_cell_angle_beta   117.33
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Ba2NbHg
_chemical_formula_sum   'Ba2 Nb1 Hg1'
_cell_volume   133.29
_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  0.5  0.0  0.5  1.0
  Ba  Ba1  1  0.75  0.0  0.47  1.0
  Nb  Nb2  1  0.0  0.0  0.0  1.0
  Hg  Hg3  1  0.47  0.72  0.47  1.0

Ba Ba Nb Hg
Ba Ba Nb Hg 0 1 + o o 0 2 + o o 1 3 o - o 1 2 o o + 1 2 o o o 2 3 o - o 
Ba2NbHg crystallizes in the triclinic P1 space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 4-coordinate geometry to one Ba(2), two equivalent Nb(1), and one Hg(1) atom. The Ba(1)-Ba(2) bond length is 1.46 Å. There is one shorter (2.80 Å) and one longer (3.61 Å) Ba(1)-Nb(1) bond length. The Ba(1)-Hg(1) bond length is 2.16 Å. In the second Ba site, Ba(2) is bonded in a distorted single-bond geometry to one Ba(1), two equivalent Nb(1), and one Hg(1) atom. There is one shorter (2.93 Å) and one longer (2.99 Å) Ba(2)-Nb(1) bond length. The Ba(2)-Hg(1) bond length is 1.46 Å. Nb(1) is bonded in a 6-coordinate geometry to two equivalent Ba(1), two equivalent Ba(2), and two equivalent Hg(1) atoms. There is one shorter (2.80 Å) and one longer (3.61 Å) Nb(1)-Hg(1) bond length. Hg(1) is bonded in a single-bond geometry to one Ba(1), one Ba(2), and two equivalent Nb(1) atoms.