data_[Rb3Si6Ge6O21]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Rb  0.8200  2.3500  1.6600
  Si  1.9000  1.1000  0.5400
  Ge  2.0100  1.2500  0.7700
  O  3.4400  0.6000  1.2600
]
_symmetry_space_group_name_H-M [R32]
_cell_length_a [5.3949]
_cell_length_b [5.3949]
_cell_length_c [24.6141]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [120.0000]
_symmetry_Int_Tables_number [155]
_chemical_formula_structural [RbSi2Ge2O7]
_chemical_formula_sum '[Rb3 Si6 Ge6 O21]'
_cell_volume [620.4169]
_cell_formula_units_Z [3]
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  3  0.0000  0.0000  0.5000  1.0
  Si  Si1  6  0.0000  0.0000  0.0665  1.0
  Ge  Ge2  6  0.0000  0.0000  0.2808  1.0
  O  O3  18  0.0079  0.4590  0.5771  1.0
  O  O4  3  0.0000  0.0000  0.0000  1.0
]