Nitrogen sulfide (S4N4) is an inorganic compound that can be found in planetary atmospheres.
Following their mission to Qo'noS in 2151, the crew of Enterprise NX-01 planned to visit an inhabited planet with a nitrogen sulfide atmosphere to begin their mission of exploration, since the planet was located only a few light years away. The expectation was that non-humanoid life would be found there. (ENT: "Broken Bow")