data_[Na4Ca12Hg28]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Na  0.9300  1.8000  1.1600
  Ca  1.0000  1.8000  1.1400
  Hg  2.0000  1.5000  1.2450
]
_symmetry_space_group_name_H-M [Cmcm]
_cell_length_a [3.8712]
_cell_length_b [20.6852]
_cell_length_c [15.1160]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [63]
_chemical_formula_structural [NaCa3Hg7]
_chemical_formula_sum '[Na4 Ca12 Hg28]'
_cell_volume [1210.4444]
_cell_formula_units_Z [4]
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  0.0730  0.7500  1
  Ca  Ca1  8  0.0000  0.0886  0.0739  1
  Ca  Ca2  4  0.0000  0.2790  0.7500  1
  Hg  Hg3  8  0.0000  0.2932  0.5507  1
  Hg  Hg4  8  0.0000  0.3232  0.1442  1
  Hg  Hg5  8  0.0000  0.4630  0.0904  1
  Hg  Hg6  4  0.0000  0.4351  0.7500  1
]