Ozone, or trioxygen, is a chemical with the symbol O3. This means one molecule of ozone is made of 3 oxygen atoms. Ozone is also called trioxygen. Ozone is formed from dioxygen by the action of ultraviolet light and also atmospheric electrical discharges. It is present in low concentrations throughout the Earth's atmosphere. In total, ozone makes up only 0.6 ppm of the atmosphere.
3D model (JSmol)
|Molar mass||48.00 g·mol−1|
|Appearance||Colourless to pale blue gas<|
|Density||2.144 mg cm−3 (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 (−12.15 °C or 10.13 °F or 261.00 K)[a]|
Refractive index (nD)
|1.2226 (liquid), 1.00052 (gas, STP, 546 nm — note high dispersion)|
|Hybridisation||sp2 for O1|
|Std enthalpy of
|142.67 kJ mol−1|
|238.92 J K−1 mol−1|
exposure limit (PEL)
|TWA 0.1 ppm (0.2 mg/m3)|
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
|what is ?)(|
Ozone is important to planet Earth. There is a portion of the stratosphere with a high concentration of ozone, called the ozone layer. The ozone layer filters out damaging ultraviolet radiation from the Sun, like a kind of sun screen. Without this ozone layer things would not have been able to live on the surface of our planet. The ozone layer also absorbs a lot of heat from the sun's rays.
However, ozone is toxic to animals and plants above concentrations of about 0.1 ppm. In humans, it can cause nasal and throat irritation, and nausea. Extended exposure can cause lung oedema. 0.100 ppm is the maximum allowable limit for industrial, public, or occupied spaces in England, Japan, France, the Netherlands and Germany. The Ozone layer is in the 10 to 50 kilometer range of the Earth's atmosphere.
- 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. doi:10.1098/rsta.1914.0001. https://archive.org/stream/philtrans08506476/08506476#page/n17/mode/1up. Retrieved 4 February 2016.
- "Stratospheric ozone". Ministry for the Environment (New Zealand). 2013-07-18. Retrieved 2014-03-03.
- "Ozone Safety Limits". Understanding Ozone. Retrieved 2013-11-21.