data_[Na2As2Se8]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Na  0.9300  1.8000  1.1600
  As  2.1800  1.1500  0.6600
  Se  2.5500  1.1500  1.0133
]
_symmetry_space_group_name_H-M [P2/c]
_cell_length_a [8.6807]
_cell_length_b [4.0562]
_cell_length_c [10.1526]
_cell_angle_alpha [90.0000]
_cell_angle_beta [109.1234]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [13]
_chemical_formula_structural [NaAsSe4]
_chemical_formula_sum '[Na2 As2 Se8]'
_cell_volume [337.7499]
_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  2  0.5000  0.2360  0.7500  1
  As  As1  2  0.0000  0.0000  0.0000  1
  Se  Se2  4  0.2135  0.4768  0.9944  1
  Se  Se3  4  0.2334  0.2413  0.2221  1
]