data_[Na2Al2Si2]
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 [Pmma]
_cell_length_a [6.9408]
_cell_length_b [5.4365]
_cell_length_c [3.7984]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [51]
_chemical_formula_structural [NaAlSi]
_chemical_formula_sum '[Na2 Al2 Si2]'
_cell_volume [143.3274]
_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  0.2500  0.0000  0.6716  1
  Al  Al1  2  0.0000  0.5000  0.5000  1
  Si  Si2  2  0.2500  0.5000  0.0264  1
]