Nitrogen monosulfide

Mononitrogen monosulfide is an inorganic compound with the formula SN. It is the sulfur analogue of the radical nitric oxide, NO. It can be produced through electrical discharges in mixtures of nitrogen and sulfur compounds, as well as the reaction of nitrogen with sulfur vapor. The valence electrons of this compound match those of nitric oxide. In outer space, this compound was first detected in the giant molecular cloud Sgr B2. It was subsequently observed in cold dark clouds and in the comae of comets.

Mononitrogen monosulfide exists as a resonance structure, of which a species with a bond order of one accompanied by charge separation is the major contributor.