data_[Na4Fe2Se6]
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
  Se  2.5500  1.1500  1.0133
]
_symmetry_space_group_name_H-M [Amm2]
_cell_length_a [18.7317]
_cell_length_b [9.4589]
_cell_length_c [7.1288]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [38]
_chemical_formula_structural [Na2FeSe3]
_chemical_formula_sum '[Na4 Fe2 Se6]'
_cell_volume [1263.0748]
_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  4  0.0000  0.2006  0.1199  1
  Fe  Fe1  2  0.0000  0.0000  0.7561  1
  Se  Se2  4  0.0996  0.0000  0.9097  1
  Se  Se3  2  0.0000  0.0000  0.4500  1
]