data_[Na20Si204]
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 [18.0516]
_cell_length_b [10.4150]
_cell_length_c [25.5844]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0223]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [12]
_chemical_formula_structural [Na5Si51]
_chemical_formula_sum '[Na20 Si204]'
_cell_volume [4810.0365]
_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  0.1250  1
  Na  Na1  4  0.1667  0.0000  0.4583  1
  Na  Na2  4  0.1667  0.0000  0.2083  1
  Na  Na3  4  0.1667  0.0000  0.8333  1
  Na  Na4  2  0.0000  0.0000  0.0000  1
  Na  Na5  2  0.0000  0.5000  0.5000  1
  Si  Si6  8  0.0025  0.1157  0.8762  1
  Si  Si7  8  0.0243  0.1960  0.5430  1
  Si  Si8  8  0.0268  0.1884  0.7903  1
  Si  Si9  8  0.0618  0.3145  0.4058  1
  Si  Si10  8  0.0628  0.3120  0.2548  1
  Si  Si11  8  0.0653  0.3039  0.0020  1
  Si  Si12  8  0.1013  0.1962  0.3313  1
  Si  Si13  8  0.1039  0.1883  0.0787  1
  Si  Si14  8  0.1048  0.1860  0.9275  1
  Si  Si15  8  0.1399  0.3116  0.5430  1
  Si  Si16  8  0.1424  0.3039  0.7904  1
  Si  Si17  8  0.1641  0.3844  0.4570  1
  Si  Si18  8  0.1692  0.3845  0.2097  1
  Si  Si19  8  0.1912  0.3042  0.8762  1
  Si  Si20  8  0.1937  0.3117  0.1238  1
  Si  Si21  8  0.2286  0.1855  0.7392  1
  Si  Si22  8  0.2294  0.1882  0.5881  1
  Si  Si23  8  0.2320  0.1961  0.3354  1
  Si  Si24  4  0.0000  0.5000  0.6254  1
  Si  Si25  4  0.0001  0.5000  0.2823  1
  Si  Si26  4  0.0360  0.0000  0.3353  1
  Si  Si27  4  0.0412  0.0000  0.5880  1
  Si  Si28  4  0.0430  0.0000  0.7391  1
  Si  Si29  4  0.1236  0.5000  0.5942  1
  Si  Si30  4  0.1254  0.5000  0.7453  1
  Si  Si31  4  0.1311  0.5000  0.9980  1
  Si  Si32  4  0.1667  0.0000  0.6156  1
  Si  Si33  4  0.1667  0.0000  0.7080  1
  Si  Si34  4  0.1669  0.0000  0.0511  1
  Si  Si35  4  0.1670  0.0000  0.9587  1
  Si  Si36  4  0.2026  0.5000  0.6687  1
  Si  Si37  4  0.2076  0.5000  0.9213  1
  Si  Si38  4  0.2093  0.5000  0.0725  1
]