data_[Na6Sr3Hg3I18]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Na  0.9300  1.8000  1.1600
  Sr  0.9500  2.0000  1.3200
  Hg  2.0000  1.5000  1.2450
  I  2.6600  1.4000  1.2733
]
_symmetry_space_group_name_H-M [R3]
_cell_length_a [8.0890]
_cell_length_b [8.0890]
_cell_length_c [21.8411]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [120.0000]
_symmetry_Int_Tables_number [146]
_chemical_formula_structural [Na2SrHgI6]
_chemical_formula_sum '[Na6 Sr3 Hg3 I18]'
_cell_volume [1237.6433]
_cell_formula_units_Z [3]
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  3  0.0000  0.0000  0.0138  1.0
  Na  Na1  3  0.0000  0.0000  0.5137  1.0
  Sr  Sr2  3  0.0000  0.0000  0.8194  1.0
  Hg  Hg3  3  0.0000  0.0000  0.3190  1.0
  I  I4  9  0.0060  0.3563  0.5850  1.0
  I  I5  9  0.0348  0.6688  0.0800  1.0
]