data_[Na12Cu4Se12]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Na  0.9300  1.8000  1.1600
  Cu  1.9000  1.3500  0.8200
  Se  2.5500  1.1500  1.0133
]
_symmetry_space_group_name_H-M [C2/m]
_cell_length_a [8.2771]
_cell_length_b [13.2962]
_cell_length_c [7.0290]
_cell_angle_alpha [90.0000]
_cell_angle_beta [114.5265]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [12]
_chemical_formula_structural [Na3CuSe3]
_chemical_formula_sum '[Na12 Cu4 Se12]'
_cell_volume [703.7714]
_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  4  0.0000  0.1479  0.5000  1
  Na  Na1  4  0.0000  0.2049  0.0000  1
  Na  Na2  4  0.1164  0.5000  0.3079  1
  Cu  Cu3  4  0.2053  0.0000  0.2026  1
  Se  Se4  8  0.1162  0.3451  0.6901  1
  Se  Se5  4  0.1061  0.0000  0.8221  1
]