data_[Rb8Mn4Nb4O20]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Rb  0.8200  2.3500  1.6600
  Mn  1.5500  1.4000  0.6483
  Nb  1.6000  1.4500  0.8200
  O  3.4400  0.6000  1.2600
]
_symmetry_space_group_name_H-M [Cmc2_1]
_cell_length_a [3.2374]
_cell_length_b [15.7754]
_cell_length_c [12.8054]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [36]
_chemical_formula_structural [Rb2MnNbO5]
_chemical_formula_sum '[Rb8 Mn4 Nb4 O20]'
_cell_volume [653.9906]
_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  0.0806  0.6608  1
  Rb  Rb1  4  0.0000  0.1417  0.3132  1
  Mn  Mn2  4  0.0000  0.4430  0.4351  1
  Nb  Nb3  4  0.0000  0.2172  0.0285  1
  O  O4  4  0.0000  0.0684  0.0151  1
  O  O5  4  0.0000  0.2895  0.6281  1
  O  O6  4  0.0000  0.3052  0.4259  1
  O  O7  4  0.0000  0.3305  0.0071  1
  O  O8  4  0.0000  0.4949  0.3101  1
]