Carbon subsulfide is an organic, sulfur-containing chemical compound with the formula and structure . This deep red liquid is immiscible with water but soluble in organic solvents. It readily polymerizes at room temperature to form a hard black solid.
C<sub>3</sub>S<sub>2</sub> was discovered by , who assigned it an unsymmetrical structure. Later, infrared and Raman spectroscopy showed that the structure is symmetrical with a D<sub>âÂÂh</sub> point group symmetry, i.e. S=C=C=C=S. This compound is analogous to carbon suboxide whose structure is O=C=C=C=O.
Lengyel first synthesized this compound by passing carbon disulfide (CS<sub>2</sub>) vapor through an electric arc with carbon electrodes. This treatment produced a black solution that after filtration and evaporation gave a cherry-red liquid. He determined the molecular mass by cryoscopy. Later preparations of C<sub>3</sub>S<sub>2</sub> include thermolysis of a stream of CS<sub>2</sub> in a quartz tube heated to 900 to 1100 ðC as well as flash vacuum pyrolysis (FVP) of 1,2-dithiole-3-thiones.
Among its few known reactions, C<sub>3</sub>S<sub>2</sub> reacts with bromine to form the cyclic disulfide.
C<sub>3</sub>S<sub>2</sub> polymerizes under applied pressure to give a black semi-conducting solid. A similar pressure-induced polymerization of CS<sub>2</sub> also gives a black semiconducting polymer.
In addition, reactions of C<sub>3</sub>S<sub>2</sub> can yield highly condensed sulfur-containing compounds, e.g. the reaction of C<sub>3</sub>S<sub>2</sub> with 2-aminopyridine.
Using microwave spectroscopy, small C<sub>n</sub>S<sub>2</sub> clusters have been detected in interstellar medium. The rotational transitions of these molecular carbon sulfides matched with the corresponding molecules.