• Hydrogen sulfide
• Chemistry
• Occurrence
• Manufacture and use
• Induced hibernation
• Participant in the sulfur cycle
• H₂S Implicated in Mass Extinctions

Hydrogen sulfide

Hydrogen sulfide (hydrogen sulphide in British English), H₂S, is a colorless, toxic, flammable gas that is responsible for the foul odor of rotten eggs and flatulence. It often results when bacteria break down organic matter in the absence of oxygen, such as in swamps, and sewers (alongside the process of anaerobic digestion). It also occurs in volcanic gases, natural gas and some well waters. This is the odor that is commonly misattributed to elemental sulfur, which is in fact odorless.

Hydrogen sulfide is also known as sulfane, sulfur hydride, sour gas, sulfurated hydrogen, hydrosulfuric acid, sewer gas and stink damp. IUPAC accepts the names "hydrogen sulfide" and "sulfane"; the latter one is used exclusively when naming more complicated compounds.