data_[Na16Cu20Se24]
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 [Cmc2_1]
_cell_length_a [4.1716]
_cell_length_b [18.4281]
_cell_length_c [15.4852]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [36]
_chemical_formula_structural [Na4Cu5Se6]
_chemical_formula_sum '[Na16 Cu20 Se24]'
_cell_volume [1190.4184]
_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  0.0022  0.5006  1
  Na  Na1  4  0.0000  0.0198  0.7647  1
  Na  Na2  4  0.0000  0.1780  0.3072  1
  Na  Na3  4  0.0000  0.1791  0.9460  1
  Cu  Cu4  4  0.0000  0.1377  0.6296  1
  Cu  Cu5  4  0.0000  0.2931  0.6300  1
  Cu  Cu6  4  0.0000  0.3564  0.2550  1
  Cu  Cu7  4  0.0000  0.3565  0.9901  1
  Cu  Cu8  4  0.0000  0.4273  0.6763  1
  Se  Se9  4  0.0000  0.1267  0.1248  1
  Se  Se10  4  0.0000  0.2143  0.4995  1
  Se  Se11  4  0.0000  0.2153  0.7604  1
  Se  Se12  4  0.0000  0.4313  0.3863  1
  Se  Se13  4  0.0000  0.4324  0.8578  1
  Se  Se14  4  0.0000  0.4425  0.1272  1
]