data_[Rb6Ca3Se6O18]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Rb  0.8200  2.3500  1.6600
  Ca  1.0000  1.8000  1.1400
  Se  2.5500  1.1500  1.0133
  O  3.4400  0.6000  1.2600
]
_symmetry_space_group_name_H-M [R-3m]
_cell_length_a [6.1180]
_cell_length_b [6.1180]
_cell_length_c [24.4101]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [120.0000]
_symmetry_Int_Tables_number [166]
_chemical_formula_structural [Rb2Ca(SeO3)2]
_chemical_formula_sum '[Rb6 Ca3 Se6 O18]'
_cell_volume [791.2649]
_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  6  0.0000  0.0000  0.2751  1.0
  Ca  Ca1  3  0.0000  0.0000  0.0000  1.0
  Se  Se2  6  0.0000  0.0000  0.4174  1.0
  O  O3  18  0.0385  0.5192  0.2792  1.0
]