data_[Na4Cr4Si2Se12]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Na  0.9300  1.8000  1.1600
  Cr  1.6600  1.4000  0.9400
  Si  1.9000  1.1000  0.5400
  Se  2.5500  1.1500  1.0133
]
_symmetry_space_group_name_H-M [C2/m]
_cell_length_a [6.3708]
_cell_length_b [11.0668]
_cell_length_c [7.3804]
_cell_angle_alpha [90.0000]
_cell_angle_beta [106.8811]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [12]
_chemical_formula_structural [Na2Cr2SiSe6]
_chemical_formula_sum '[Na4 Cr4 Si2 Se12]'
_cell_volume [497.9248]
_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  4  0.0000  0.1680  0.0000  1.0
  Cr  Cr1  4  0.0000  0.3319  0.5000  1.0
  Si  Si2  2  0.0000  0.0000  0.5000  1.0
  Se  Se3  8  0.2293  0.1632  0.6952  1.0
  Se  Se4  4  0.2423  0.5000  0.6932  1.0
]