data_[Na2Er2I8]
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
  I  2.6600  1.4000  1.2733
]
_symmetry_space_group_name_H-M [P2_1/m]
_cell_length_a [15.7663]
_cell_length_b [4.4783]
_cell_length_c [18.9723]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [11]
_chemical_formula_structural [NaErI4]
_chemical_formula_sum '[Na2 Er2 I8]'
_cell_volume [1339.5532]
_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  0.4064  0.2500  0.5136  1
  Er  Er1  2  0.1360  0.7500  0.5021  1
  I  I2  2  0.0382  0.2500  0.5861  1
  I  I3  2  0.1911  0.2500  0.4073  1
  I  I4  2  0.2662  0.7500  0.6047  1
  I  I5  2  0.4250  0.7500  0.4067  1
]