data_[Ca4Cu4O8]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Ca  1.0000  1.8000  1.1400
  Cu  1.9000  1.3500  0.8200
  O  3.4400  0.6000  1.2600
]
_symmetry_space_group_name_H-M [P2_12_12]
_cell_length_a [5.4603]
_cell_length_b [11.1351]
_cell_length_c [3.2029]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [18]
_chemical_formula_structural [CaCuO2]
_chemical_formula_sum '[Ca4 Cu4 O8]'
_cell_volume [194.7356]
_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
[
  Ca  Ca0  4  0.0244  0.1373  0.5046  1.0
  Cu  Cu1  4  0.0150  0.3781  0.9929  1.0
  O  O2  4  0.2267  0.7543  0.9990  1.0
  O  O3  4  0.2435  0.0061  0.0155  1.0
]