Hydrogen Sulfide: Chemical compound

It often results when bacteria break down organic matter if there is no oxygen. This happens in swamps, and sewers (alongside the process of anaerobic digestion). It also happens in volcanic gases, natural gas and some well waters. This is the smell that people often think to be that of sulfur. But sulfur itself does not smell.

Hydrogen sulfide

Names
Systematic IUPAC name Hydrogen sulfide
Other names Dihydrogen monosulfide Dihydrogen sulfide Sewer gas Sulfane Sulfurated hydrogen Sulfureted hydrogen Sulfuretted hydrogen Sulfur hydride Hydrosulfuric acid Hydrothionic acid Thiohydroxic acid Sulfhydric acid
Identifiers
CAS Number	7783-06-4 Y
3D model (JSmol)	Interactive image
3DMet	B01206
Beilstein Reference	3535004
ChEBI	CHEBI:16136 Y
ChEMBL	ChEMBL1200739 N
ChemSpider	391 Y
ECHA InfoCard	100.029.070
EC Number	231-977-3
Gmelin Reference	303
KEGG	C00283 Y
MeSH	Hydrogen+sulfide
PubChem CID	402
RTECS number	MX1225000
UNII	YY9FVM7NSN Y
UN number	1053
CompTox Dashboard (EPA)	DTXSID4024149
SMILES [H]S[H]
Properties
Chemical formula	H2S
Molar mass	34.08 g·mol−1
Appearance	Colorless gas
Odor	Rotten eggs
Density	1.363 g dm−3
Melting point	−82 °C (−116 °F; 191 K)
Boiling point	−60 °C (−76 °F; 213 K)
Solubility in water	4 g dm−3 (at 20 °C)
Vapor pressure	1740 kPa (at 21 °C)
Acidity (pKa)	7.0
Conjugate acid	Sulfonium
Conjugate base	Bisulfide
Magnetic susceptibility (χ)	−25.5·10−6 cm3/mol
Refractive index (nD)	1.000644 (0 °C)
Structure
Point group	C2v
Molecular shape	Bent
Dipole moment	0.97 D
Thermochemistry
Std enthalpy of formation ΔfHo298	−21 kJ mol−1
Standard molar entropy So298	206 J mol−1 K−1
Specific heat capacity, C	1.003 J K−1 g−1
Hazards
EU classification	F+ T+ N
Main hazards	Flammable and highly toxic
NFPA 704	4 4 0
R-phrases	R12, R26, R50
S-phrases	(S1/2), S9, S16, S36, S38, S45, S61
Explosive limits	4.3–46%
U.S. Permissible exposure limit (PEL)	C 20 ppm; 50 ppm [10-minute maximum peak]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is YN ?)
Infobox references

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". When people speak of more complicated compounds they always use the term "sulfane".

 

Small amounts of hydrogen sulfide can be found in crude petroleum. Sour natural gas can contain up to 28%. But, sour natural gas must be cleaned before it can enter a long distance pipeline. Pipelines limit hydrogen sulfide to 3 grains per thousand cubic feet of natural gas. Volcanoes and hot springs give off some H₂S, where it probably is made by the hydrolysis of sulfide minerals, i.e. MS + H₂O to give MO + H₂S.

Normal average concentration in clean air is about 0.0001-0.0002 ppm.

Hydrogen sulfide is a highly toxic and flammable gas. Because it is heavier than air it tends to accumulate at the bottom of poorly ventilated spaces.

Hydrogen sulfide is considered a broad-spectrum poison, meaning that it can poison several different systems in the body, although the nervous system is most affected. The toxicity of H₂S is comparable with that of hydrogen cyanide.

• "Hydrogen Sulfide", Committee on Medical and Biological Effects of Environmental Pollutants, University Park Press, 1979, Baltimore. ISBN 0-8391-0127-9

• International Chemical Safety Card 0165
• Concise International Chemical Assessment Document 53
• National Pollutant Inventory - Hydrogen sulfide fact sheet Archived 2006-03-09 at the Wayback Machine
• NIOSH Pocket Guide to Chemical Hazards
• MSDS safety data sheet Archived 2007-05-15 at the Wayback Machine
• Abstract of survey article on H₂S as used by the body, by P. Kamoun
• Computational Chemistry Wiki Archived 2008-12-07 at the Wayback Machine