data_[Rb6Nb2Se8]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Rb  0.8200  2.3500  1.6600
  Nb  1.6000  1.4500  0.8200
  Se  2.5500  1.1500  1.0133
]
_symmetry_space_group_name_H-M [Imm2]
_cell_length_a [7.5045]
_cell_length_b [10.6898]
_cell_length_c [8.1440]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [44]
_chemical_formula_structural [Rb3NbSe4]
_chemical_formula_sum '[Rb6 Nb2 Se8]'
_cell_volume [653.3232]
_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  0.2420  0.4260  1.0
  Rb  Rb1  2  0.0000  0.0000  0.0018  1.0
  Nb  Nb2  2  0.0000  0.5000  0.9952  1.0
  Se  Se3  4  0.0000  0.3097  0.8305  1.0
  Se  Se4  4  0.2431  0.0000  0.6695  1.0
]