data_[Na8Nb4Tl4Se16]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Na  0.9300  1.8000  1.1600
  Nb  1.6000  1.4500  0.8200
  Tl  1.6200  1.9000  1.3325
  Se  2.5500  1.1500  1.0133
]
_symmetry_space_group_name_H-M [Fmm2]
_cell_length_a [10.3222]
_cell_length_b [10.8041]
_cell_length_c [8.1853]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [42]
_chemical_formula_structural [Na2NbTlSe4]
_chemical_formula_sum '[Na8 Nb4 Tl4 Se16]'
_cell_volume [912.8439]
_cell_formula_units_Z [4]
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
[
  Na  Na0  8  0.2500  0.2500  0.0856  1.0
  Nb  Nb1  4  0.0000  0.0000  0.5517  1.0
  Tl  Tl2  4  0.0000  0.0000  0.0492  1.0
  Se  Se3  8  0.0000  0.1866  0.3840  1.0
  Se  Se4  8  0.1882  0.0000  0.7299  1.0
]