Hydrogen Sulfide — properties & hazards overview
Boiling point
−60 °C
Flash point
−82 °C
Explosion limits (air)
4.3–45.5 vol%
Vapour density (air=1)
~ 1.2 (heavier than air)
Toxicity
rapid respiratory paralysis
Flammability
wide explosive range
Chronic risk
mainly acute hazard
Environmental
odour / sulfides
| Property | Value / Note |
|---|---|
| Chemical formula | H₂S |
| Molar mass | 34.08 g/mol |
| Physical state (20 °C) | Colourless gas with characteristic “rotten egg” odour |
| Odour threshold | ~ 0.01–0.3 ppm (olfactory fatigue above ~100 ppm — smell is unreliable) |
| Solubility in water | Moderate; forms weak acids (H₂S ⇌ HS⁻ + H⁺) |
| Reactivity | Flammable, corrosive; reacts with metals to form metal sulfides |
| Typical sources/uses | Petroleum refining, natural gas processing, wastewater, pulp & paper, biogas plants |
*Values are indicative; always consult current SDS and regulations for design and safety.