Benzene
Benzene is an organic chemical compound with the molecular formula C6H6. The benzene molecule is composed of six carbon atoms joined in a planar hexagonal ring with one hydrogen atom attached to each. Because it contains only carbon and hydrogen atoms, benzene is classed as a hydrocarbon.
Space-filling model | |||
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Benzene at room temperature | |||
| Names | |||
|---|---|---|---|
| Preferred IUPAC name
Benzene | |||
| Other names
Benzol (historic/German) Phenane Phenylene hydride Cyclohexa-1,3,5-triene; 1,3,5-Cyclohexatriene (theoretical resonance isomers) [6]Annulene (not recommended) Phene (historic) | |||
| Identifiers | |||
3D model (JSmol) |
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| ChEBI | |||
| ChEMBL | |||
| ChemSpider | |||
| ECHA InfoCard | 100.000.685 | ||
| EC Number |
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| KEGG | |||
PubChem CID |
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| RTECS number |
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| UNII | |||
CompTox Dashboard (EPA) |
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| Properties | |||
| C6H6 | |||
| Molar mass | 78.114 g·mol−1 | ||
| Appearance | Colorless liquid | ||
| Odor | sweet aromatic | ||
| Density | 0.8765(20) g/cm3 | ||
| Melting point | 5.53 °C (41.95 °F; 278.68 K) | ||
| Boiling point | 80.1 °C (176.2 °F; 353.2 K) | ||
| 1.53 g/L (0 °C) 1.81 g/L (9 °C) 1.79 g/L (15 °C) 1.84 g/L (30 °C) 2.26 g/L (61 °C) 3.94 g/L (100 °C) 21.7 g/kg (200 °C, 6.5 MPa) 17.8 g/kg (200 °C, 40 MPa) | |||
| Solubility | Soluble in alcohol, CHCl3, CCl4, diethyl ether, acetone, acetic acid | ||
| Solubility in ethanediol | 5.83 g/100 g (20 °C) 6.61 g/100 g (40 °C) 7.61 g/100 g (60 °C) | ||
| Solubility in ethanol | 20 °C, solution in ethanol: 1.2 mL/L (20% v/v) | ||
| Solubility in acetone | 20 °C, solution in acetone: 7.69 mL/L (38.46% v/v) 49.4 mL/L (62.5% v/v) | ||
| Solubility in diethylene glycol | 52 g/100 g (20 °C) | ||
| log P | 2.13 | ||
| Vapor pressure | 12.7 kPa (25 °C) 24.4 kPa (40 °C) 181 kPa (100 °C) | ||
| Conjugate acid | Benzenium | ||
| Conjugate base | Benzenide | ||
| UV-vis (λmax) | 255 nm | ||
| −54.8·10−6 cm3/mol | |||
Refractive index (nD) |
1.5011 (20 °C) 1.4948 (30 °C) | ||
| Viscosity | 0.7528 cP (10 °C) 0.6076 cP (25 °C) 0.4965 cP (40 °C) 0.3075 cP (80 °C) | ||
| Structure | |||
| Trigonal planar | |||
| 0 D | |||
| Thermochemistry | |||
Heat capacity (C) |
134.8 J/mol·K | ||
Std molar entropy (S⦵298) |
173.26 J/mol·K | ||
Std enthalpy of formation (ΔfH⦵298) |
48.7 kJ/mol | ||
Std enthalpy of combustion (ΔcH⦵298) |
-3267.6 kJ/mol | ||
| Hazards | |||
| Occupational safety and health (OHS/OSH): | |||
Main hazards |
potential occupational carcinogen, flammable | ||
| GHS labelling: | |||
| Danger | |||
| H225, H302, H304, H305, H315, H319, H340, H350, H372, H410 | |||
| P201, P210, P301+P310, P305+P351+P338, P308+P313, P331 | |||
| NFPA 704 (fire diamond) | |||
| Flash point | −11.63 °C (11.07 °F; 261.52 K) | ||
| 497.78 °C (928.00 °F; 770.93 K) | |||
| Explosive limits | 1.2–7.8% | ||
| Lethal dose or concentration (LD, LC): | |||
LD50 (median dose) |
930 mg/kg (rat, oral) | ||
LCLo (lowest published) |
44,000 ppm (rabbit, 30 min) 44,923 ppm (dog) 52,308 ppm (cat) 20,000 ppm (human, 5 min) | ||
| NIOSH (US health exposure limits): | |||
PEL (Permissible) |
TWA 1 ppm, ST 5 ppm | ||
REL (Recommended) |
Ca TWA 0.1 ppm ST 1 ppm | ||
IDLH (Immediate danger) |
500 ppm | ||
| Safety data sheet (SDS) | HMDB | ||
| Related compounds | |||
Related compounds |
Toluene Borazine | ||
| Supplementary data page | |||
| Benzene (data page) | |||
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references | |||
Benzene is a natural constituent of petroleum and is one of the elementary petrochemicals. Due to the cyclic continuous pi bonds between the carbon atoms, benzene is classed as an aromatic hydrocarbon. Benzene is a colorless and highly flammable liquid with a sweet smell, and is partially responsible for the aroma of gasoline. It is used primarily as a precursor to the manufacture of chemicals with more complex structures, such as ethylbenzene and cumene, of which billions of kilograms are produced annually. Although benzene is a major industrial chemical, it finds limited use in consumer items because of its toxicity. Benzene is a volatile organic compound.
Benzene is classified as a carcinogen.