data_BaMgHg2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.01
_cell_length_b   4.01
_cell_length_c   7.63
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   92.17
_symmetry_Int_Tables_number   1
_chemical_formula_structural   BaMgHg2
_chemical_formula_sum   'Ba1 Mg1 Hg2'
_cell_volume   122.82
_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  0.78  0.0  0.8  1.0
  Mg  Mg3  1  0.0  0.0  0.43  1.0
  Hg  Hg1  1  0.0  0.0  0.39  1.0
  Hg  Hg2  1  0.78  0.0  0.44  1.0

data_BaMgHg2
_symmetry_space_group_name_H-M   Pm
_cell_length_a   4.01
_cell_length_b   4.01
_cell_length_c   7.63
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   6
_chemical_formula_structural   BaMgHg2
_chemical_formula_sum   'Ba1 Mg1 Hg2'
_cell_volume   122.91
_cell_formula_units_Z   1
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  '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  0.78  0.0  0.8  1.0
  Mg  Mg1  1  0.0  0.0  0.43  1.0
  Hg  Hg2  1  0.0  0.0  0.39  1.0
  Hg  Hg3  1  0.78  0.0  0.44  1.0

Ba Mg Hg Hg
Ba Mg Hg Hg 0 2 + o o 0 1 + o o 0 3 o o o 1 2 o o o 1 3 - o o 2 3 - o o 
BaMgHg2 crystallizes in the monoclinic Pm space group. The structure is zero-dimensional and consists of one BaMgHg2 cluster. Ba(1) is bonded in a distorted single-bond geometry to one Hg(2) atom. The Ba(1)-Hg(2) bond length is 2.74 Å. Mg(1) is bonded in a distorted L-shaped geometry to one Hg(1) and one Hg(2) atom. The Mg(1)-Hg(1) bond length is 0.34 Å. The Mg(1)-Hg(2) bond length is 0.87 Å. There are two inequivalent Hg sites. In the first Hg site, Hg(1) is bonded in a single-bond geometry to one Mg(1) atom. In the second Hg site, Hg(2) is bonded in a single-bond geometry to one Ba(1) and one Mg(1) atom.