data_[Rb4Cu4O8]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Rb  0.8200  2.3500  1.6600
  Cu  1.9000  1.3500  0.8200
  O  3.4400  0.6000  1.2600
]
_symmetry_space_group_name_H-M [Cmcm]
_cell_length_a [4.9342]
_cell_length_b [11.9336]
_cell_length_c [5.5058]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [63]
_chemical_formula_structural [RbCuO2]
_chemical_formula_sum '[Rb4 Cu4 O8]'
_cell_volume [324.1988]
_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
[
  Rb  Rb0  4  0.0000  0.3094  0.2500  1.0
  Cu  Cu1  4  0.0000  0.0022  0.2500  1.0
  O  O2  8  0.0000  0.1031  0.5041  1.0
]