Hydrogen sulfide

Sulfur, S   Hydrogen, H
Names
Systematic IUPAC name Hydrogen sulfide[1]
Other names Dihydrogen monosulfide Sour gas Dihydrogen sulfide Sewer gas Egg 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
InChI InChI=1S/H2S/h1H2 Y Key: RWSOTUBLDIXVET-UHFFFAOYSA-N Y InChI=1/H2S/h1H2 Key: RWSOTUBLDIXVET-UHFFFAOYAJ
SMILES S
Properties
Chemical formula	H2S
Molar mass	34.08 g·mol−1
Appearance	Colorless gas
Odor	Foul, pungent, like that of rotten eggs
Density	1.539 g.L−1 (0°C)[2]
Melting point	−85.5[3] °C (−121.9 °F; 187.7 K)
Boiling point	−59.55[3] °C (−75.19 °F; 213.60 K)
Solubility in water	3.980 g dm−3 (at 20 °C) [4]
Vapor pressure	1740 kPa (at 21 °C)
Acidity (pKa)	7.0[5][6]
Conjugate acid	Sulfonium
Conjugate base	Bisulfide
Magnetic susceptibility (χ)	−25.5·10−6 cm3/mol
Refractive index (nD)	1.000644 (0 °C)[2]
Structure
Point group	C2v
Molecular shape	Bent
Dipole moment	0.97 D
Thermochemistry
Heat capacity (C)	1.003 J K−1 g−1
Std molar entropy (S⦵298)	206 J mol−1 K−1[7]
Std enthalpy of formation (ΔfH⦵298)	−21 kJ mol−1[7]
Hazards
Occupational safety and health (OHS/OSH):
Main hazards	Flammable and highly toxic
GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H220, H330, H400
Precautionary statements	P210, P260, P271, P273, P284, P304+P340, P310, P320, P377, P381, P391, P403, P403+P233, P405, P501
NFPA 704 (fire diamond)	4 4 0
Flash point	−82.4 °C (−116.3 °F; 190.8 K)[10]
Autoignition temperature	232 °C (450 °F; 505 K)
Explosive limits	4.3–46%
Lethal dose or concentration (LD, LC):
LC50 (median concentration)	713 ppm (rat, 1 hr) 673 ppm (mouse, 1 hr) 634 ppm (mouse, 1 hr) 444 ppm (rat, 4 hr)[9]
LCLo (lowest published)	600 ppm (human, 30 min) 800 ppm (human, 5 min)[9]
NIOSH (US health exposure limits):
PEL (Permissible)	C 20 ppm; 50 ppm [8]
REL (Recommended)	C 10 ppm (15 mg/m3) [8]
IDLH (Immediate danger)	100 ppm[8]
Related compounds
Related hydrogen chalcogenides	Water Hydrogen selenide Hydrogen telluride Hydrogen polonide Hydrogen disulfide Sulfanyl
Related compounds	Phosphine
Except where otherwise noted, data are given for materials in their standard state (at 25 °C , 100 kPa). N verify (what is YN ?) Infobox references

Hydrogen sulfide is a chemical compound with the formula H₂S. It is a colorless chalcogen-hydride gas, and is poisonous, corrosive, and flammable, with trace amounts in ambient atmosphere having a characteristic foul odor of rotten eggs.^[11] Swedish chemist Carl Wilhelm Scheele is credited with having discovered the chemical composition of purified hydrogen sulfide in 1777.^[12]

Hydrogen sulfide is toxic to humans and most other animals by inhibiting cellular respiration in a manner similar to hydrogen cyanide. When it is inhaled or its salts are ingested in high amounts,^{[clarification needed]} damage to organs occurs rapidly with symptoms ranging from breathing difficulties to convulsions and death.^[13][14] Despite this, the human body produces small amounts of this sulfide and its mineral salts, and uses it as a signalling molecule.^[15]

Hydrogen sulfide is often produced from the microbial breakdown of organic matter in the absence of oxygen, such as in swamps and sewers; this process is commonly known as anaerobic digestion, which is done by sulfate-reducing microorganisms. It also occurs in volcanic gases, natural gas deposits, and sometimes in well-drawn water.

Properties

Hydrogen sulfide is slightly denser than air. A mixture of H₂S and air can be explosive.

Oxidation

In general, hydrogen sulfide acts as a reducing agent, as indicated by its ability to reduce sulfur dioxide in the Claus process. Hydrogen sulfide burns in oxygen with a blue flame to form sulfur dioxide (SO₂) and water:

2 H₂S + 3 O₂ → 2 SO₂ + 2 H₂O

If an excess of oxygen is present, sulfur trioxide (SO₃) is formed, which quickly hydrates to sulfuric acid:

H₂S + 2 O₂ → H₂SO₄

Zdroj:https://en.wikipedia.org?pojem=Hydrogen_sulfide
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