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Names | |||
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Systematic IUPAC name
Hydrogen sulfide[1] | |||
Other names
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Identifiers | |||
3D model (JSmol)
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3DMet | |||
3535004 | |||
ChEBI | |||
ChEMBL | |||
ChemSpider | |||
ECHA InfoCard | 100.029.070 | ||
EC Number |
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303 | |||
KEGG | |||
MeSH | Hydrogen+sulfide | ||
PubChem CID
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RTECS number |
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UNII | |||
UN number | 1053 | ||
CompTox Dashboard (EPA)
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Properties | |||
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) | ||
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 | ||
−25.5·10−6 cm3/mol | |||
Refractive index (nD)
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1.000644 (0 °C)[2] | ||
Structure | |||
C2v | |||
Bent | |||
0.97 D | |||
Thermochemistry | |||
Heat capacity (C)
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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
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Flammable and highly toxic | ||
GHS labelling: | |||
Danger | |||
H220, H330, H400 | |||
P210, P260, P271, P273, P284, P304+P340, P310, P320, P377, P381, P391, P403, P403+P233, P405, P501 | |||
NFPA 704 (fire diamond) | |||
Flash point | −82.4 °C (−116.3 °F; 190.8 K)[10] | ||
232 °C (450 °F; 505 K) | |||
Explosive limits | 4.3–46% | ||
Lethal dose or concentration (LD, LC): | |||
LC50 (median concentration)
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LCLo (lowest published)
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NIOSH (US health exposure limits): | |||
PEL (Permissible)
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C 20 ppm; 50 ppm [10-minute maximum peak][8] | ||
REL (Recommended)
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C 10 ppm (15 mg/m3) [10-minute][8] | ||
IDLH (Immediate danger)
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100 ppm[8] | ||
Related compounds | |||
Related hydrogen chalcogenides
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Related compounds
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Phosphine | ||
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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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.
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