data_SeI2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.23
_cell_length_b   8.23
_cell_length_c   3.94
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   SeI2
_chemical_formula_sum   'Se2 I4'
_cell_volume   266.98
_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
  Se  Se4  1  0.0  0.0  0.0  1.0
  Se  Se5  1  0.12  0.12  0.97  1.0
  I  I0  1  0.69  0.69  0.0  1.0
  I  I1  1  0.55  0.55  0.0  1.0
  I  I2  1  0.81  0.43  0.97  1.0
  I  I3  1  0.43  0.81  0.97  1.0

data_SeI2
_symmetry_space_group_name_H-M   Cm
_cell_length_a   11.65
_cell_length_b   11.65
_cell_length_c   3.94
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   SeI2
_chemical_formula_sum   'Se4 I8'
_cell_volume   533.95
_cell_formula_units_Z   4
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
  Se  Se0  2  0.0  0.0  0.0  1.0
  Se  Se1  2  0.12  0.0  0.97  1.0
  I  I2  4  0.12  0.31  0.97  1.0
  I  I3  2  0.05  0.5  -0.0  1.0
  I  I4  2  0.19  0.5  -0.0  1.0

Se Se I I I I