data_[K6Na18Hg18]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  K  0.8200  2.2000  1.5200
  Na  0.9300  1.8000  1.1600
  Hg  2.0000  1.5000  1.2450
]
_symmetry_space_group_name_H-M [R-3]
_cell_length_a [8.4479]
_cell_length_b [8.4479]
_cell_length_c [21.2489]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [120.0000]
_symmetry_Int_Tables_number [148]
_chemical_formula_structural [K(NaHg)3]
_chemical_formula_sum '[K6 Na18 Hg18]'
_cell_volume [1313.2923]
_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
[
  K  K0  6  0.0000  0.0000  0.3502  1
  Na  Na1  18  0.0493  0.4340  0.8752  1
  Hg  Hg2  18  0.0040  0.2283  0.0599  1
]