data_CSe3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.48
_cell_length_b   8.48
_cell_length_c   3.13
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   132.15
_symmetry_Int_Tables_number   1
_chemical_formula_structural   CSe3
_chemical_formula_sum   'C2 Se6'
_cell_volume   166.9
_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
  C  C0  1  0.44  0.22  0.78  1.0
  C  C1  1  0.44  0.78  0.35  1.0
  Se  Se2  1  0.44  0.12  0.78  1.0
  Se  Se3  1  0.44  0.88  0.35  1.0
  Se  Se4  1  0.9  0.75  0.78  1.0
  Se  Se5  1  0.98  0.25  0.35  1.0
  Se  Se6  1  0.9  0.25  0.35  1.0
  Se  Se7  1  0.98  0.75  0.78  1.0

data_CSe3
_symmetry_space_group_name_H-M   P-1
_cell_length_a   3.13
_cell_length_b   6.87
_cell_length_c   8.48
_cell_angle_alpha   113.93
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   2
_chemical_formula_structural   CSe3
_chemical_formula_sum   'C2 Se6'
_cell_volume   166.9
_cell_formula_units_Z   2
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  '-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  Se0  2  0.28  0.75  0.21  1.0
  Se  Se1  2  0.28  0.12  0.12  1.0
  C  C2  2  0.28  0.22  0.22  1.0
  Se  Se3  2  0.28  0.75  0.29  1.0

C C Se Se Se Se Se Se
SeC(Se)2 is Cubane-like structured and crystallizes in the triclinic P-1 space group. The structure is zero-dimensional and consists of two diselenium molecules and two selenoformaldehyde molecules.