data_[Na8Si4]
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
]
_symmetry_space_group_name_H-M [C2/m]
_cell_length_a [10.9329]
_cell_length_b [3.7568]
_cell_length_c [8.3214]
_cell_angle_alpha [90.0000]
_cell_angle_beta [107.6924]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [12]
_chemical_formula_structural [Na2Si]
_chemical_formula_sum '[Na8 Si4]'
_cell_volume [325.6172]
_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  0.0215  0.5000  0.1903  1.0
  Na  Na1  4  0.1654  0.0000  0.6306  1.0
  Si  Si2  4  0.2094  0.0000  0.0508  1.0
]