data_BaMg2Hg
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.72
_cell_length_b   3.72
_cell_length_c   8.61
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   BaMg2Hg
_chemical_formula_sum   'Ba1 Mg2 Hg1'
_cell_volume   119.02
_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
  Mg  Mg2  1  0.86  0.86  0.88  1.0
  Mg  Mg3  1  0.86  0.86  0.73  1.0
  Hg  Hg1  1  0.0  0.0  0.31  1.0

data_BaMg2Hg
_symmetry_space_group_name_H-M   Cm
_cell_length_a   5.26
_cell_length_b   5.26
_cell_length_c   8.61
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   BaMg2Hg
_chemical_formula_sum   'Ba2 Mg4 Hg2'
_cell_volume   238.04
_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
  Mg  Mg1  2  0.36  0.5  0.73  1.0
  Mg  Mg2  2  0.36  0.5  0.88  1.0
  Hg  Hg3  2  0.0  0.0  0.31  1.0

Ba Mg Mg Hg
BaMg2Hg crystallizes in the monoclinic Cm space group. The structure is zero-dimensional and consists of two BaMg2Hg clusters. Ba(1) is bonded in a 2-coordinate geometry to one Mg(1) and one Hg(1) atom. The Ba(1)-Mg(1) bond length is 1.28 Å. The Ba(1)-Hg(1) bond length is 2.64 Å. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a distorted single-bond geometry to one Ba(1) and one Mg(2) atom. The Mg(1)-Mg(2) bond length is 1.25 Å. In the second Mg site, Mg(2) is bonded in a single-bond geometry to one Mg(1) atom. Hg(1) is bonded in a single-bond geometry to one Ba(1) atom.