Isomers among the carbon sulfides C<sub>4</sub>S<sub>6</sub>—synthesis and crystal structures of α,α-C<sub>4</sub>S<sub>6</sub>, α,β-C<sub>4</sub>S<sub>6</sub>, and of a second polymorph of the diiodine adduct α,β-C<sub>4</sub>S<sub>6</sub>·I<sub>2</sub>
beta-C4S6. The molecular rearrangement can be induced by a short thermal treatment at 150 degrees C. Significant differences are found in the mass spectra fragmentation patterns. Only alpha,beta-C4S6 shows an intense signal for C3S2+ and is therefore a potential source for the synthesis of carbon subsulfide via flash vacuum pyrolysis. Only alpha,beta-C4S6 forms a stable adduct with I2. alpha,beta-C4S6.I2