data_MgCrHg
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.73
_cell_length_b   6.73
_cell_length_c   6.73
_cell_angle_alpha   155.42
_cell_angle_beta   155.42
_cell_angle_gamma   35.04
_symmetry_Int_Tables_number   1
_chemical_formula_structural   MgCrHg
_chemical_formula_sum   'Mg1 Cr1 Hg1'
_cell_volume   52.7
_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
  Mg  Mg2  1  0.0  0.0  0.43  1.0
  Cr  Cr0  1  0.0  0.0  0.02  1.0
  Hg  Hg1  1  0.0  0.0  0.38  1.0

data_MgCrHg
_symmetry_space_group_name_H-M   Cm
_cell_length_a   4.05
_cell_length_b   4.05
_cell_length_c   6.73
_cell_angle_alpha   90.0
_cell_angle_beta   107.52
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   MgCrHg
_chemical_formula_sum   'Mg2 Cr2 Hg2'
_cell_volume   105.39
_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
  Mg  Mg0  2  0.43  0.0  0.43  1.0
  Cr  Cr1  2  0.02  0.0  0.02  1.0
  Hg  Hg2  2  0.38  0.0  0.38  1.0

Mg Cr Hg
Mg Cr Hg 0 2 o o o 0 1 o o o 1 1 + o + 1 1 o + + 1 2 o o o 
MgCrHg crystallizes in the monoclinic Cm space group. The structure is zero-dimensional and consists of two MgCrHg clusters. Mg(1) is bonded in a single-bond geometry to one Hg(1) atom. The Mg(1)-Hg(1) bond length is 0.30 Å. Cr(1) is bonded in a distorted single-bond geometry to one Hg(1) atom. The Cr(1)-Hg(1) bond length is 2.41 Å. Hg(1) is bonded in a single-bond geometry to one Mg(1) and one Cr(1) atom.