  We present the first detection of HCNS (thiofulminic acid) in space with the
QUIJOTE line survey in the direction of TMC-1. We performed a complete study of
the isomers of CHNS and CHNO, including NCO and NCS. The derived column
densities for HCNS, HNCS, and HSCN are (9.0+/-0.5)e9, (3.2+/-0.1)e11, and
(8.3+/-0.4)e11 cm-2, respectively. The HNCS/HSCN abundance ratio is 0.38. The
abundance ratios HNCO/HNCS, HCNO/HCNS, HOCN/HSCN, and NCO/NCS are 34+/-4,
8.3+/-0.7, 0.18+/-0.03, and 0.78+/-0.07, respectively. These ratios cannot be
correctly reproduced by our gas-phase chemical models, which suggests that
formation paths for these species are missing, and/or that the adopted
dissociative recombination rates for their protonated precursors have to be
revised. The isotopologues H15NCO, DNCO, N13CO, DCNO, H34SCN, and DSCN have
also been detected with the ultrasensitive QUIJOTE line survey.
