data_[Rb4Sr4Nb2O12]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Rb  0.8200  2.3500  1.6600
  Sr  0.9500  2.0000  1.3200
  Nb  1.6000  1.4500  0.8200
  O  3.4400  0.6000  1.2600
]
_symmetry_space_group_name_H-M [C2/m]
_cell_length_a [6.2406]
_cell_length_b [10.5688]
_cell_length_c [6.9035]
_cell_angle_alpha [90.0000]
_cell_angle_beta [106.6972]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [12]
_chemical_formula_structural [Rb2Sr2NbO6]
_chemical_formula_sum '[Rb4 Sr4 Nb2 O12]'
_cell_volume [436.1308]
_cell_formula_units_Z [2]
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  0.1650  0.0000  1
  Sr  Sr1  4  0.0000  0.3382  0.5000  1
  Nb  Nb2  2  0.0000  0.0000  0.5000  1
  O  O3  8  0.1893  0.1413  0.6693  1
  O  O4  4  0.2163  0.0000  0.3278  1
]