data_[Na8Np8Se20]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Na  0.9300  1.8000  1.1600
  Np  1.3600  1.7500  1.0000
  Se  2.5500  1.1500  1.0133
]
_symmetry_space_group_name_H-M [Cmce]
_cell_length_a [14.7882]
_cell_length_b [7.7865]
_cell_length_c [7.8213]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [64]
_chemical_formula_structural [Na2Np2Se5]
_chemical_formula_sum '[Na8 Np8 Se20]'
_cell_volume [900.6181]
_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  0.2027  0.0000  0.0000  1
  Np  Np1  8  0.0000  0.1580  0.6585  1
  Se  Se2  16  0.1248  0.1480  0.3530  1
  Se  Se3  4  0.0000  0.0000  0.0000  1
]