data_[Na4Nb2Cu2S8]
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
  Cu  1.9000  1.3500  0.8200
  S  2.5800  1.0000  0.8800
]
_symmetry_space_group_name_H-M [Pmn2_1]
_cell_length_a [7.8087]
_cell_length_b [7.4547]
_cell_length_c [6.7554]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [31]
_chemical_formula_structural [Na2NbCuS4]
_chemical_formula_sum '[Na4 Nb2 Cu2 S8]'
_cell_volume [393.2392]
_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
[
  Na  Na0  4  0.2483  0.6874  0.0038  1.0
  Nb  Nb1  2  0.0000  0.1638  0.9984  1.0
  Cu  Cu2  2  0.0000  0.8337  0.4956  1.0
  S  S3  4  0.2485  0.3202  0.9191  1.0
  S  S4  2  0.0000  0.1060  0.3294  1.0
  S  S5  2  0.0000  0.8983  0.8307  1.0
]