data_[Na8Fe4O8]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Na  0.9300  1.8000  1.1600
  Fe  1.8300  1.4000  0.8525
  O  3.4400  0.6000  1.2600
]
_symmetry_space_group_name_H-M [Cmc2_1]
_cell_length_a [3.0069]
_cell_length_b [10.6696]
_cell_length_c [8.4422]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [36]
_chemical_formula_structural [Na2FeO2]
_chemical_formula_sum '[Na8 Fe4 O8]'
_cell_volume [270.8419]
_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  0.1096  0.6528  1
  Na  Na1  4  0.0000  0.3581  0.8343  1
  Fe  Fe2  4  0.0000  0.3766  0.4958  1
  O  O3  4  0.0000  0.0156  0.9086  1
  O  O4  4  0.0000  0.2288  0.0936  1
]