data_[Si8Se4]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Si  1.9000  1.1000  0.5400
  Se  2.5500  1.1500  1.0133
]
_symmetry_space_group_name_H-M [Cm]
_cell_length_a [11.0481]
_cell_length_b [3.5169]
_cell_length_c [6.5063]
_cell_angle_alpha [90.0000]
_cell_angle_beta [103.7091]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [8]
_chemical_formula_structural [Si2Se]
_chemical_formula_sum '[Si8 Se4]'
_cell_volume [245.5963]
_cell_formula_units_Z [4]
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  0.1388  0.5000  0.5399  1
  Si  Si1  2  0.1556  0.5000  0.9159  1
  Si  Si2  2  0.2868  0.0000  0.4815  1
  Si  Si3  2  0.4592  0.5000  0.5348  1
  Se  Se4  2  0.2979  0.0000  0.1144  1
  Se  Se5  2  0.4950  0.5000  0.9134  1
]