data_Si2Sn2Se
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.88
_cell_length_b   5.88
_cell_length_c   5.88
_cell_angle_alpha   130.29
_cell_angle_beta   130.29
_cell_angle_gamma   72.95
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Si2Sn2Se
_chemical_formula_sum   'Si2 Sn2 Se1'
_cell_volume   115.3
_cell_formula_units_Z   1
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  Si1  1  0.0  0.0  0.89  1.0
  Si  Si2  1  0.0  0.0  0.56  1.0
  Sn  Sn3  1  0.0  0.47  0.36  1.0
  Sn  Sn4  1  0.47  0.0  0.36  1.0
  Se  Se0  1  0.0  0.0  0.0  1.0

data_Si2Sn2Se
_symmetry_space_group_name_H-M   Cm
_cell_length_a   6.99
_cell_length_b   6.99
_cell_length_c   5.88
_cell_angle_alpha   90.0
_cell_angle_beta   126.48
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   Si2Sn2Se
_chemical_formula_sum   'Si4 Sn4 Se2'
_cell_volume   230.59
_cell_formula_units_Z   2
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  'x, -y, z'
  3  'x+1/2, y+1/2, z'
  4  'x+1/2, -y+1/2, 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  0.11  0.0  0.11  1.0
  Si  Si1  2  0.44  0.0  0.44  1.0
  Sn  Sn2  4  0.37  0.27  0.11  1.0
  Se  Se3  2  0.0  0.0  0.0  1.0

Si Si Sn Sn Se