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| Names | |||
|---|---|---|---|
| IUPAC name
Ozone
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| Systematic IUPAC name
Trioxygen | |||
| Other names
2λ4-trioxidiene; catena-trioxygen
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| Identifiers | |||
3D model (JSmol)
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| ChEBI | |||
| ChemSpider | |||
| ECHA InfoCard | 100.030.051 | ||
| EC Number |
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| 1101 | |||
| MeSH | Ozone | ||
PubChem CID
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| RTECS number |
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| UNII | |||
CompTox Dashboard (EPA)
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| Properties | |||
| O3 | |||
| Molar mass | 47.997 g·mol−1 | ||
| Appearance | Colourless to pale blue gas[1] | ||
| Odor | Pungent[1] | ||
| Density | 2.144 g/L (at 0 °C) | ||
| Melting point | −192.2 °C; −313.9 °F; 81.0 K | ||
| Boiling point | −112 °C; −170 °F; 161 K | ||
| 1.05 g L−1 (at 0 °C) | |||
| Solubility in other solvents | Very soluble in CCl4, sulfuric acid | ||
| Vapor pressure | 55.7 atm[2] (−12.15 °C or 10.13 °F or 261.00 K)[a] | ||
| Conjugate acid | Protonated ozone | ||
| +6.7·10−6 cm3/mol | |||
Refractive index (nD)
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1.2226 (liquid), 1.00052 (gas, STP, 546 nm—note high dispersion)[3] | ||
| Structure | |||
| C2v | |||
| Digonal | |||
| Dihedral | |||
| Hybridisation | sp2 for O1 | ||
| 0.53 D | |||
| Thermochemistry | |||
Std molar
entropy (S⦵298) |
238.92 J K−1 mol−1 | ||
Std enthalpy of
formation (ΔfH⦵298) |
142.67 kJ mol−1 | ||
| Hazards | |||
| GHS labelling: | |||
     
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| Danger | |||
| H270, H314, H330, H335, H341, H361, H370, H410 | |||
| P203, P220, P244, P260, P264+P265, P270, P271, P273, P280, P284, P301+P330+P331, P302+P361+P354, P304+P340, P305+P351+P338, P308+P316, P362+P364, P370+P376, P391, P403+P233, P405 | |||
| NFPA 704 (fire diamond) | |||
| Lethal dose or concentration (LD, LC): | |||
LCLo (lowest published)
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12.6 ppm (mouse, 3 hr) 50 ppm (human, 30 min) 36 ppm (rabbit, 3 hr) 21 ppm (mouse, 3 hr) 21.8 ppm (rat, 3 hr) 24.8 ppm (guinea pig, 3 hr) 4.8 ppm (rat, 4 hr)[4] | ||
| NIOSH (US health exposure limits): | |||
PEL (Permissible)
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TWA 0.1 ppm (0.2 mg/m3)[1] | ||
REL (Recommended)
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C 0.1 ppm (0.2 mg/m3)[1] | ||
IDLH (Immediate danger)
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5 ppm[1] | ||
| Related compounds | |||
Related compounds
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Sulfur dioxide Trisulfur Disulfur monoxide Cyclic ozone | ||
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Ozone (/ˈoʊzoʊn/) (or trioxygen) is an inorganic molecule with the chemical formula O
3. It is a pale blue gas with a distinctively pungent smell. It is an allotrope of oxygen that is much less stable than the diatomic allotrope O
2, breaking down in the lower atmosphere to O
2 (dioxygen). Ozone is formed from dioxygen by the action of ultraviolet (UV) light and electrical discharges within the Earth's atmosphere. It is present in very low concentrations throughout the atmosphere, with its highest concentration high in the ozone layer of the stratosphere, which absorbs most of the Sun's ultraviolet (UV) radiation.
Ozone's odor is reminiscent of chlorine, and detectable by many people at concentrations of as little as 0.1 ppm in air. Ozone's O3 structure was determined in 1865. The molecule was later proven to have a bent structure and to be weakly diamagnetic. In standard conditions, ozone is a pale blue gas that condenses at cryogenic temperatures to a dark blue liquid and finally a violet-black solid. Ozone's instability with regard to more common dioxygen is such that both concentrated gas and liquid ozone may decompose explosively at elevated temperatures, physical shock, or fast warming to the boiling point.[5][6] It is therefore used commercially only in low concentrations.
Ozone is a powerful oxidant (far more so than dioxygen) and has many industrial and consumer applications related to oxidation. This same high oxidizing potential, however, causes ozone to damage mucous and respiratory tissues in animals, and also tissues in plants, above concentrations of about 0.1 ppm. While this makes ozone a potent respiratory hazard and pollutant near ground level, a higher concentration in the ozone layer (from two to eight ppm) is beneficial, preventing damaging UV light from reaching the Earth's surface.
- ^ a b c d e NIOSH Pocket Guide to Chemical Hazards. "#0476". National Institute for Occupational Safety and Health (NIOSH).
- ^ Gas Encyclopedia; Ozone
- ^ Cuthbertson, Clive; Cuthbertson, Maude (1914). "On the Refraction and Dispersion of the Halogens, Halogen Acids, Ozone, Steam Oxides of Nitrogen, and Ammonia". Philosophical Transactions of the Royal Society A. 213 (497–508): 1–26. Bibcode:1914RSPTA.213....1C. doi:10.1098/rsta.1914.0001. Retrieved 4 February 2016.
- ^ "Ozone". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
- ^ Streng, A. G. (1961). "Tables of Ozone Properties". Journal of Chemical & Engineering Data. 6 (3): 431–436. doi:10.1021/je00103a031.
- ^ Batakliev, Todor; Georgiev, Vladimir; Anachkov, Metody; Rakovsky, Slavcho; Zaikov, Gennadi E. (June 2014). "Ozone decomposition". Interdisciplinary Toxicology. 7 (2): 47–59. doi:10.2478/intox-2014-0008. ISSN 1337-6853. PMC 4427716. PMID 26109880.
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