data_[Na2Er2Hg8]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Na  0.9300  1.8000  1.1600
  Er  1.2400  1.7500  1.0300
  Hg  2.0000  1.5000  1.2450
]
_symmetry_space_group_name_H-M [C2/m]
_cell_length_a [10.4948]
_cell_length_b [3.8310]
_cell_length_c [7.8486]
_cell_angle_alpha [90.0000]
_cell_angle_beta [112.3507]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [12]
_chemical_formula_structural [NaErHg4]
_chemical_formula_sum '[Na2 Er2 Hg8]'
_cell_volume [291.8485]
_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  2  0.0000  0.0000  0.0000  1
  Er  Er1  2  0.0000  0.0000  0.5000  1
  Hg  Hg2  4  0.1646  0.5000  0.3360  1
  Hg  Hg3  4  0.1696  0.5000  0.8314  1
]