data_[Na2Fe2O4]
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 [Pmn2_1]
_cell_length_a [2.9775]
_cell_length_b [6.5118]
_cell_length_c [4.6910]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [31]
_chemical_formula_structural [NaFeO2]
_chemical_formula_sum '[Na2 Fe2 O4]'
_cell_volume [90.9546]
_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  0.6177  0.2417  1.0
  Fe  Fe1  2  0.0000  0.1269  0.2184  1.0
  O  O2  2  0.0000  0.0874  0.7921  1.0
  O  O3  2  0.0000  0.6733  0.7478  1.0
]