data_BaTaHg2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.31
_cell_length_b   3.31
_cell_length_c   9.07
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   BaTaHg2
_chemical_formula_sum   'Ba1 Ta1 Hg2'
_cell_volume   99.22
_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  0.0  1.0
  Ta  Ta3  1  0.0  0.0  0.54  1.0
  Hg  Hg1  1  0.65  0.65  0.67  1.0
  Hg  Hg2  1  0.65  0.65  0.4  1.0

data_BaTaHg2
_symmetry_space_group_name_H-M   Cm
_cell_length_a   4.68
_cell_length_b   4.68
_cell_length_c   9.07
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   BaTaHg2
_chemical_formula_sum   'Ba2 Ta2 Hg4'
_cell_volume   198.44
_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  0.0  1.0
  Ta  Ta1  2  0.0  0.0  0.54  1.0
  Hg  Hg2  2  0.15  0.5  0.4  1.0
  Hg  Hg3  2  0.15  0.5  0.67  1.0

Ba Ta Hg Hg
BaTaHg2 crystallizes in the monoclinic Cm space group. Ba(1) is bonded in a 8-coordinate geometry to four equivalent Ba(1), one Hg(2), and three equivalent Hg(1) atoms. All Ba(1)-Ba(1) bond lengths are 3.31 Å. The Ba(1)-Hg(2) bond length is 3.99 Å. There is one shorter (3.39 Å) and two longer (3.86 Å) Ba(1)-Hg(1) bond lengths. Ta(1) is bonded in a 2-coordinate geometry to one Hg(1) and one Hg(2) atom. The Ta(1)-Hg(1) bond length is 2.03 Å. The Ta(1)-Hg(2) bond length is 2.03 Å. There are two inequivalent Hg sites. In the first Hg site, Hg(1) is bonded in a distorted single-bond geometry to three equivalent Ba(1) and one Ta(1) atom. In the second Hg site, Hg(2) is bonded in a distorted single-bond geometry to one Ba(1) and one Ta(1) atom.