Hydrogen Sulfide, a compound of hydrogen and sulfur. This highly poisonous gas has the odor of rotten eggs. It is colorless, tastes sweet, burns easily, and is soluble in water and many organic compounds (such as alcohol). Hydrogen sulfide is formed by decay of sulfur-bearing proteins, found in most living matter. The compound also occurs in most volcanic and natural gases, petroleum deposits, and mineral waters. It is usually made by treating sulfides with acids. Main uses are in analyzing chemicals and making sulfur compounds and antihistamines.

Chemical formula: H2 S.