data_Mg2Hg3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   11.56
_cell_length_b   11.56
_cell_length_c   11.56
_cell_angle_alpha   17.18
_cell_angle_beta   17.18
_cell_angle_gamma   17.18
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Mg2Hg3
_chemical_formula_sum   'Mg2 Hg3'
_cell_volume   117.69
_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  Mg3  1  0.0  0.0  0.65  1.0
  Mg  Mg4  1  0.0  0.0  0.52  1.0
  Hg  Hg0  1  0.0  0.0  0.0  1.0
  Hg  Hg1  1  0.0  0.0  0.93  1.0
  Hg  Hg2  1  0.0  0.0  0.24  1.0

data_Mg2Hg3
_symmetry_space_group_name_H-M   Cm
_cell_length_a   5.98
_cell_length_b   3.45
_cell_length_c   11.56
_cell_angle_alpha   90.0
_cell_angle_beta   99.93
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   Mg2Hg3
_chemical_formula_sum   'Mg4 Hg6'
_cell_volume   235.38
_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  0.0  0.0  0.35  1.0
  Mg  Mg1  2  0.0  0.0  0.48  1.0
  Hg  Hg2  2  0.0  0.0  0.0  1.0
  Hg  Hg3  2  0.0  0.0  0.07  1.0
  Hg  Hg4  2  0.0  0.0  0.76  1.0

Mg Mg Hg Hg Hg