Hydrogen peroxide is a chemical compound with the formula H2O2. In its pure form, it is a very pale blue liquid that is slightly more viscous than water. It is used as an oxidizer, bleaching agent, and antiseptic, usually as a dilute solution in water for consumer use, and in higher concentrations for industrial use. Concentrated hydrogen peroxide, or "high-test peroxide", decomposes explosively when heated and has been used both as a monopropellant and an oxidizer in rocketry.
Ozone 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 latter, with its highest concentration high in the ozone layer of the stratosphere, which absorbs most of the Sun's ultraviolet (UV) radiation.
An oxidizing agent is a substance in a redox chemical reaction that gains or "accepts"/"receives" an electron from a reducing agent. In other words, an oxidizer is any substance that oxidizes another substance. The oxidation state, which describes the degree of loss of electrons, of the oxidizer decreases while that of the reductant increases; this is expressed by saying that oxidizers "undergo reduction" and "are reduced" while reducers "undergo oxidation" and "are oxidized". Common oxidizing agents are oxygen, hydrogen peroxide, and the halogens.
Nitric oxide is a colorless gas with the formula NO. It is one of the principal oxides of nitrogen. Nitric oxide is a free radical: it has an unpaired electron, which is sometimes denoted by a dot in its chemical formula. Nitric oxide is also a heteronuclear diatomic molecule, a class of molecules whose study spawned early modern theories of chemical bonding.
Chemiluminescence is the emission of light (luminescence) as the result of a chemical reaction. There may also be limited emission of heat. Given reactants A and B, with an excited intermediate ◊,
Dinitrogen pentoxide is the chemical compound with the formula N2O5. It is one of the binary nitrogen oxides, a family of compounds that only contain nitrogen and oxygen. It exists as colourless crystals that sublime slightly above room temperature, yielding a colorless gas.
The ozone–oxygen cycle is the process by which ozone is continually regenerated in Earth's stratosphere, converting ultraviolet radiation (UV) into heat. In 1930 Sydney Chapman resolved the chemistry involved. The process is commonly called the Chapman cycle by atmospheric scientists.
The hydroxyl radical is the diatomic molecule •
OH. The hydroxyl radical is very stable as a dilute gas, but it decays very rapidly in the condensed phase. It is pervasive in some situations. Most notably the hydroxyl radicals are produced from the decomposition of hydroperoxides (ROOH) or, in atmospheric chemistry, by the reaction of excited atomic oxygen with water. It is also important in the field of radiation chemistry, since it leads to the formation of hydrogen peroxide and oxygen, which can enhance corrosion and SCC in coolant systems subjected to radioactive environments. The unpaired electron of the hydroxyl radical is officially represented by a middle dot, •, beside the O.
Benzoyl peroxide is a chemical compound (specifically, an organic peroxide) with structural formula (C6H5−C(=O)O−)2, often abbreviated as (BzO)2. In terms of its structure, the molecule can be described as two benzoyl (C6H5−C(=O)−, Bz) groups connected by a peroxide (−O−O−). It is a white granular solid with a faint odour of benzaldehyde, poorly soluble in water but soluble in acetone, ethanol, and many other organic solvents. Benzoyl peroxide is an oxidizer, which is principally used as in the production of polymers.
Oxygen fluorides are compounds of elements oxygen and fluorine with the general formula OnF2, where n = 1 to 6. Many different oxygen fluorides are known:
In atmospheric chemistry, NOx is shorthand for nitric oxide and nitrogen dioxide, the nitrogen oxides that are most relevant for air pollution. These gases contribute to the formation of smog and acid rain, as well as affecting tropospheric ozone.
The hydroperoxyl radical, also known as the hydrogen superoxide, is the protonated form of superoxide with the chemical formula HO2, also written HOO•. This species plays an important role in the atmosphere and as a reactive oxygen species in cell biology.
Photodissociation, photolysis, photodecomposition, or photofragmentation is a chemical reaction in which molecules of a chemical compound are broken down by photons. It is defined as the interaction of one or more photons with one target molecule.
Manganese(VII) oxide (manganese heptoxide) is an inorganic compound with the formula Mn2O7. This volatile liquid is highly reactive. It is a dangerous oxidizer and was first described in 1860. It is the acid anhydride of permanganic acid.
Advanced oxidation processes (AOPs), in a broad sense, are a set of chemical treatment procedures designed to remove organic (and sometimes inorganic) materials in water and wastewater by oxidation through reactions with hydroxyl radicals (·OH). In real-world applications of wastewater treatment, however, this term usually refers more specifically to a subset of such chemical processes that employ ozone (O3), hydrogen peroxide (H2O2) and/or UV light.
There are several known allotropes of oxygen. The most familiar is molecular oxygen, present at significant levels in Earth's atmosphere and also known as dioxygen or triplet oxygen. Another is the highly reactive ozone. Others are:
Dioxygen plays an important role in the energy metabolism of living organisms. Free oxygen is produced in the biosphere through photolysis of water during photosynthesis in cyanobacteria, green algae, and plants. During oxidative phosphorylation in cellular respiration, oxygen is reduced to water, thus closing the biological water-oxygen redox cycle.
Explosophores are functional groups in organic chemistry that give organic compounds explosive properties.
Hydrogen polyoxides are chemical compounds that consist only of hydrogen and oxygen atoms, are bonded exclusively by single bonds, and are acyclic. They can, therefore, be classed as hydrogen chalcogenides.
In atmospheric chemistry, a null cycle is a catalytic cycle that simply interconverts chemical species without leading to net production or removal of any component. In the stratosphere, null cycles and when the null cycles are broken are very important to the ozone layer.
