data_[Na4Al4Si4]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Na  0.9300  1.8000  1.1600
  Al  1.6100  1.2500  0.6750
  Si  1.9000  1.1000  0.5400
]
_symmetry_space_group_name_H-M [Aem2]
_cell_length_a [7.3924]
_cell_length_b [5.0204]
_cell_length_c [6.6447]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [39]
_chemical_formula_structural [NaAlSi]
_chemical_formula_sum '[Na4 Al4 Si4]'
_cell_volume [246.6015]
_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  0.5000  0.0000  0.4759  1
  Al  Al1  4  0.1174  0.2500  0.8370  1
  Si  Si2  4  0.2017  0.2500  0.2088  1
]