The linear triatomic species dicarbon sulfide (C2S) was identified
in 1987 in the interstellar cloud TMC-1 by
Saito et al.
and in the circumstellar shell
IRC +10216 by
Cernicharo et al. It was
suggested by Velusamy et al. that
the presence of C2S in protostellar objects might indicate that they are very young, but
later work by Lai & Crutcher and
de Gregorio-Monsalvo et al.
concluded that most YSOs do
not exhibit the molecule.
C2S is too unstable to exist on earth outside of a laboratory. It is
related to another observed astromolecule, C2O.