data_[Na2Ac2Si2Se8]
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
  Se  2.5500  1.1500  1.0133
]
_symmetry_space_group_name_H-M [P2_1/m]
_cell_length_a [6.9859]
_cell_length_b [6.9959]
_cell_length_c [8.6956]
_cell_angle_alpha [90.0000]
_cell_angle_beta [104.2225]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [11]
_chemical_formula_structural [NaAcSiSe4]
_chemical_formula_sum '[Na2 Ac2 Si2 Se8]'
_cell_volume [411.9499]
_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  0.2186  0.2500  0.0414  1
  Ac  Ac1  2  0.2324  0.2500  0.5542  1
  Si  Si2  2  0.2267  0.7500  0.2980  1
  Se  Se3  4  0.0121  0.0045  0.2510  1
  Se  Se4  2  0.3769  0.7500  0.5659  1
  Se  Se5  2  0.4330  0.7500  0.1357  1
]