data_[Na4Si4As4Se16]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Na  0.9300  1.8000  1.1600
  Si  1.9000  1.1000  0.5400
  As  2.1800  1.1500  0.6600
  Se  2.5500  1.1500  1.0133
]
_symmetry_space_group_name_H-M [Cmcm]
_cell_length_a [7.8592]
_cell_length_b [11.6411]
_cell_length_c [8.8140]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [63]
_chemical_formula_structural [NaSiAsSe4]
_chemical_formula_sum '[Na4 Si4 As4 Se16]'
_cell_volume [806.3872]
_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  0.5000  0.0000  1
  Si  Si1  4  0.0000  0.1307  0.2500  1
  As  As2  4  0.0000  0.1564  0.7500  1
  Se  Se3  8  0.0000  0.2411  0.0421  1
  Se  Se4  8  0.2191  0.0061  0.7500  1
]