4,5‐Propyl­enedi­thio‐1,3‐di­thiole‐2‐thione and 4,5‐propyl­enedi­thio‐1,3‐di­thiol‐2‐one

4,5‐Propyl­ene­di­thio‐1,3‐di­thiole‐2‐thione, C₆H₆S₅, (I), crystallizes in the centrosymmetric space group P2₁/c. The molecular packing is characterized by pairs of S?S intermolecular contacts between neighbouring mol­ecules, which may account for the rather high thermal stablity of the crystal. 4,5‐Propyl­ene­di­thio‐1,3‐di­thiol‐2‐one, C₆H₆OS₄, (II), in which an O atom replaces the terminal S atom of (I), crystallizes in the non‐centrosymmetric polar space group Cc. The packing pattern of (II) indicates that the macropolarization direction is along 101]. Although the packing patterns are qualitatively significantly different, the molecular structures of (I) and (II) are similar, each exhibiting a chair conformation.