data_[Rb4Si2Se6]
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
  Se  2.5500  1.1500  1.0133
]
_symmetry_space_group_name_H-M [Pmc2_1]
_cell_length_a [19.3753]
_cell_length_b [5.0007]
_cell_length_c [12.4009]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [26]
_chemical_formula_structural [Rb2SiSe3]
_chemical_formula_sum '[Rb4 Si2 Se6]'
_cell_volume [1201.5124]
_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  0.3871  0.3376  0.6011  1
  Si  Si1  2  0.5000  0.0556  0.3700  1
  Se  Se2  4  0.3981  0.1706  0.3068  1
  Se  Se3  2  0.5000  0.1554  0.0261  1
]