Discovery of thiofulminic acid with the QUIJOTE line survey: A study of the isomers of HNCS and HNCO in TMC-1

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) x 10(9), (3.2 +/- 0.1) x 10(11), and (8.3 +/- 0.4) x 10(11) 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 (HNCO)-N-15, DNCO, (HNCO)-C-13, DCNO, (HSCN)-S-34, and DSCN have also been detected with the ultrasensitive QUIJOTE line survey.