Hydrogen sulfide

Properties

General
Name	Hydrogen sulfide
Chemical formula	H2S
Appearance	Colourless gas
Physical
Formula weight	34.1 amu
Melting point	187 K (-86 °C)
Boiling point	213 K (-60 °C)
Solubility	0.33 g in 100g water
Thermochemistry
ΔfH0gas	-20.5 kJ/mol
ΔfH0liquid	? kJ/mol
ΔfH0solid	? kJ/mol
S0gas, 1 bar	205.77 J/mol·K
S0liquid, 1 bar	? J/mol·K
S0solid	? J/mol·K
Safety
Ingestion	May cause nausea and vomiting.
Inhalation	Dangerous, may be fatal. Symptoms are diverse - see reference.
Skin	May cause severe pain and itching.
Eyes	May cause burns.
More info	Hazardous Chemical Database
SI units were used where possible. Unless otherwise stated, standard conditions were used. Disclaimer and references

The chemical compound hydrogen sulfide (Hydrogen sulphide in British English) H₂S is a sulfide compound that has an unpleasant smell; it is responsible for the smell of rotten eggs. This gas can suffocate sewer workers and is often associated with other decay smells in swamps. Hydrogen sulfide is produced by the breakdown of sulfur-containing proteins and is responsible for much of the foul odor of feces and flatulence.

Hydrogen sulfide occurs naturally in crude petroleum, natural gas, volcanic gases, and hot springs. It can also result from bacterial breakdown of organic matter. It is also produced by human and animal wastes.

Hydrogen sulfide can also result from industrial activities, such as food processing, coke ovens, kraft paper mills, tanneries, and petroleum refineries.

It is an acidic gas which reacts with alkali and metals like silver. This is the reason why silver jewellery turns black when exposed to polluted atmosphere for a long duration. The Silver_sulphide resulting from the reaction is black in colour.

Health effects

Hydrogen sulfide is considered a broad-spectrum poison, meaning it can poison several different systems in the body. Breathing very high levels of hydrogen sulfide can cause death within just a few breaths. There could be loss of consciousness after one or more breaths.

Exposure to lower concentrations can result in eye irritation, a sore throat and cough, shortness of breath, and fluid in the lungs. These symptoms usually go away in a few weeks. Long-term, low-level exposure may result in fatigue, loss of appetite, headaches, irritability, poor memory, and dizziness.

Animal studies showed that pigs that ate food containing hydrogen sulfide had diarrhea after a few days and weight loss after about 105 days.