data_[Si2Ge2Se2]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Si  1.9000  1.1000  0.5400
  Ge  2.0100  1.2500  0.7700
  Se  2.5500  1.1500  1.0133
]
_symmetry_space_group_name_H-M [P1]
_cell_length_a [4.5590]
_cell_length_b [5.5039]
_cell_length_c [6.0188]
_cell_angle_alpha [77.2894]
_cell_angle_beta [67.9572]
_cell_angle_gamma [83.7168]
_symmetry_Int_Tables_number [1]
_chemical_formula_structural [SiGeSe]
_chemical_formula_sum '[Si2 Ge2 Se2]'
_cell_volume [136.4930]
_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  1  0.5736  0.3588  0.9233  1
  Si  Si1  1  0.6718  0.5393  0.2172  1
  Ge  Ge2  1  0.2714  0.4982  0.6433  1
  Ge  Ge3  1  0.8630  0.9676  0.0223  1
  Se  Se4  1  0.0501  0.2106  0.2640  1
  Se  Se5  1  0.3716  0.9204  0.7089  1
]