data_[Na18Hg12]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Na  0.9300  1.8000  1.1600
  Hg  2.0000  1.5000  1.2450
]
_symmetry_space_group_name_H-M [R-3c]
_cell_length_a [6.8328]
_cell_length_b [6.8328]
_cell_length_c [22.9502]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [120.0000]
_symmetry_Int_Tables_number [167]
_chemical_formula_structural [Na3Hg2]
_chemical_formula_sum '[Na18 Hg12]'
_cell_volume [927.9385]
_cell_formula_units_Z [6]
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
[
  Na  Na0  18  0.0000  0.4386  0.2500  1.0
  Hg  Hg1  12  0.0000  0.0000  0.1868  1.0
]