data_MgNbHg2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.91
_cell_length_b   9.91
_cell_length_c   9.91
_cell_angle_alpha   18.12
_cell_angle_beta   18.12
_cell_angle_gamma   18.12
_symmetry_Int_Tables_number   1
_chemical_formula_structural   MgNbHg2
_chemical_formula_sum   'Mg1 Nb1 Hg2'
_cell_volume   82.13
_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  0.0  1.0
  Nb  Nb3  1  0.0  0.0  0.61  1.0
  Hg  Hg0  1  0.0  0.0  0.92  1.0
  Hg  Hg1  1  0.0  0.0  0.3  1.0

data_MgNbHg2
_symmetry_space_group_name_H-M   Cm
_cell_length_a   5.4
_cell_length_b   3.12
_cell_length_c   9.91
_cell_angle_alpha   90.0
_cell_angle_beta   100.48
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   MgNbHg2
_chemical_formula_sum   'Mg2 Nb2 Hg4'
_cell_volume   164.25
_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  0.0  1.0
  Nb  Nb1  2  -0.0  0.0  0.39  1.0
  Hg  Hg2  2  -0.0  0.0  0.7  1.0
  Hg  Hg3  2  -0.0  0.0  0.08  1.0

Mg Nb Hg Hg