data_[Na6Sn8Hg8]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Na  0.9300  1.8000  1.1600
  Sn  1.9600  1.4500  0.8300
  Hg  2.0000  1.5000  1.2450
]
_symmetry_space_group_name_H-M [Immm]
_cell_length_a [4.5048]
_cell_length_b [8.5428]
_cell_length_c [16.3815]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [71]
_chemical_formula_structural [Na3(SnHg)4]
_chemical_formula_sum '[Na6 Sn8 Hg8]'
_cell_volume [630.4168]
_cell_formula_units_Z [2]
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  4  0.0000  0.0000  0.1208  1.0
  Na  Na1  2  0.0000  0.5000  0.0000  1.0
  Sn  Sn2  8  0.0000  0.2003  0.3315  1.0
  Hg  Hg3  4  0.0000  0.3214  0.5000  1.0
  Hg  Hg4  4  0.0000  0.5000  0.2286  1.0
]