data_[Ca4O4]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Ca  1.0000  1.8000  1.1400
  O  3.4400  0.6000  1.2600
]
_symmetry_space_group_name_H-M [P-1]
_cell_length_a [6.4844]
_cell_length_b [17.7926]
_cell_length_c [17.7926]
_cell_angle_alpha [120.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [2]
_chemical_formula_structural [CaO]
_chemical_formula_sum '[Ca4 O4]'
_cell_volume [1777.7950]
_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  2  0.2500  0.5183  0.9957  1
  Ca  Ca1  2  0.2500  0.3613  0.0316  1
  O  O2  2  0.0371  0.4540  0.0543  1
  O  O3  2  0.4629  0.4041  0.9779  1
]