data_[Na6Cu8Se8]
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 [Immm]
_cell_length_a [4.2348]
_cell_length_b [7.0276]
_cell_length_c [13.7629]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [71]
_chemical_formula_structural [Na3(CuSe)4]
_chemical_formula_sum '[Na6 Cu8 Se8]'
_cell_volume [409.5941]
_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  0.0000  0.0000  0.1098  1.0
  Na  Na1  2  0.0000  0.5000  0.0000  1.0
  Cu  Cu2  8  0.0000  0.1876  0.3260  1.0
  Se  Se3  4  0.0000  0.2722  0.5000  1.0
  Se  Se4  4  0.0000  0.5000  0.2287  1.0
]