data_[Na2Cr8O16]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Na  0.9300  1.8000  1.1600
  Cr  1.6600  1.4000  0.9400
  O  3.4400  0.6000  1.2600
]
_symmetry_space_group_name_H-M [I4/m]
_cell_length_a [9.8540]
_cell_length_b [9.8540]
_cell_length_c [2.9883]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [87]
_chemical_formula_structural [NaCr4O8]
_chemical_formula_sum '[Na2 Cr8 O16]'
_cell_volume [290.1691]
_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  0.5000  1.0
  Cr  Cr1  8  0.1521  0.6655  0.5000  1.0
  O  O2  8  0.0401  0.3371  0.5000  1.0
  O  O3  8  0.1519  0.8012  0.0000  1.0
]