data_[Si2Sn4Se8]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Si  1.9000  1.1000  0.5400
  Sn  1.9600  1.4500  0.8300
  Se  2.5500  1.1500  1.0133
]
_symmetry_space_group_name_H-M [P2_1/m]
_cell_length_a [7.0660]
_cell_length_b [6.8707]
_cell_length_c [8.6708]
_cell_angle_alpha [90.0000]
_cell_angle_beta [107.1817]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [11]
_chemical_formula_structural [Si(SnSe2)2]
_chemical_formula_sum '[Si2 Sn4 Se8]'
_cell_volume [402.1636]
_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
[
  Si  Si0  2  0.2977  0.2500  0.2130  1.0
  Sn  Sn1  2  0.2051  0.7500  0.9338  1.0
  Sn  Sn2  2  0.2894  0.7500  0.4452  1.0
  Se  Se3  4  0.4846  0.0049  0.7195  1.0
  Se  Se4  2  0.0783  0.2500  0.3617  1.0
  Se  Se5  2  0.1269  0.2500  0.9435  1.0
]