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 [Pm]
_cell_length_a [4.7592]
_cell_length_b [3.8658]
_cell_length_c [8.1069]
_cell_angle_alpha [90.0000]
_cell_angle_beta [94.4826]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [6]
_chemical_formula_structural [SiGeSe]
_chemical_formula_sum '[Si2 Ge2 Se2]'
_cell_volume [148.6940]
_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  0.5122  0.5000  0.9531  1
  Si  Si1  1  0.7501  0.0000  0.8517  1
  Ge  Ge2  1  0.0802  0.5000  0.7606  1
  Ge  Ge3  1  0.7465  0.0000  0.3699  1
  Se  Se4  1  0.4284  0.5000  0.2352  1
  Se  Se5  1  0.4293  0.0000  0.6088  1
]