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 [P31m]
_cell_length_a [6.5029]
_cell_length_b [6.5029]
_cell_length_c [18.7707]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [120.0000]
_symmetry_Int_Tables_number [157]
_chemical_formula_structural [CaO]
_chemical_formula_sum '[Ca4 O4]'
_cell_volume [687.4240]
_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  3  0.0000  0.6949  0.5300  1
  Ca  Ca1  1  0.0000  0.0000  0.3413  1
  O  O2  3  0.0000  0.3605  0.5422  1
  O  O3  1  0.0000  0.0000  0.4422  1
]