data_[Na1Ac1Si4]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Na  0.9300  1.8000  1.1600
  Ac  1.1000  1.9500  1.2600
  Si  1.9000  1.1000  0.5400
]
_symmetry_space_group_name_H-M [Pmmm]
_cell_length_a [4.1727]
_cell_length_b [4.6707]
_cell_length_c [6.9680]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [47]
_chemical_formula_structural [NaAcSi4]
_chemical_formula_sum '[Na1 Ac1 Si4]'
_cell_volume [135.8016]
_cell_formula_units_Z [1]
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  1  0.5000  0.0000  0.0000  1
  Ac  Ac1  1  0.0000  0.0000  0.5000  1
  Si  Si2  2  0.0000  0.5000  0.1686  1
  Si  Si3  2  0.5000  0.5000  0.3300  1
]