data_[Ca4Fe2O8]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Ca  1.0000  1.8000  1.1400
  Fe  1.8300  1.4000  0.8525
  O  3.4400  0.6000  1.2600
]
_symmetry_space_group_name_H-M [I4/mmm]
_cell_length_a [3.8108]
_cell_length_b [3.8108]
_cell_length_c [11.8625]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [139]
_chemical_formula_structural [Ca2FeO4]
_chemical_formula_sum '[Ca4 Fe2 O8]'
_cell_volume [172.2691]
_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
[
  Ca  Ca0  4  0.0000  0.0000  0.3562  1.0
  Fe  Fe1  2  0.0000  0.0000  0.0000  1.0
  O  O2  4  0.0000  0.0000  0.1651  1.0
  O  O3  4  0.0000  0.5000  0.0000  1.0
]