Caesium sulfide
Caesium sulfide is an inorganic salt with a chemical formula Cs2S. It is a strong alkali in aqueous solution. In the air, caesium sulfide emits rotten egg smelling hydrogen sulfide.
Production
Similar to sodium sulfide, anhydrous caesium sulfide can be produced by reacting caesium and sulfur in THF. It needs ammonia or naphthalene to react.By dissolving hydrogen sulfide into caesium hydroxide solution, it will produce caesium bisulfide, then it will produce caesium sulfide too.