The presence of the sulfonium ion (H3S+) was sought via its
10-00 rotational transition at 293.4572 GHz toward a number of sources by
Neufeld et al. using the
Institut de Radioastronomie Millimétrique (IRAM)
30m telescope on
Pico Valeta in southern Spain.
Four other sulfur-containing molecules were successfully detected by the study: SH, H2S, CS, and SO.
The five objects where H3S+ was searched for include the star-forming regions
W31C, G29.96-0.02, G34.2+0.1,
W51. The upper limit derived for
H3S+ relative to
H2S—τ(H3S+)/τ(H2S)—was about 0.01.
The 10-00 rotational transition of H3S+ was measured by
Saito et al. in 1987.
or protonated hydrogen sulfide is analogous to the known astromolecule,
Both compounds are pyramidal. In organic chemistry,
sulfonium is also the generic term for any
tricoordinated sulfur cation (SR1R2R3)+. A large number of
sulfonium salts have been