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Lewis dot structure of a Hydroxide ion compared to a hydroxyl radical. In chemistry, a radical, also known as a free radical, is an atom, molecule, or ion that has at least one unpaired valence electron. [1] [2] With some exceptions, these unpaired electrons make radicals highly chemically reactive. Many radicals spontaneously dimerize. Most ...
The hydroxyl radical can damage virtually all types of macromolecules: carbohydrates, nucleic acids , lipids (lipid peroxidation) and amino acids (e.g. conversion of Phe to m-Tyrosine and o-Tyrosine). The hydroxyl radical has a very short in vivo half-life of approximately 10 −9 seconds and a high reactivity. [5]
The hydroxyl radical • OH combines with H 2 S to form HS • and water. [21] Other reactions investigated by Tiee (1981) are HS • + ethylene, HS • + O 2 → HO • + SO, and reactions with itself HS • + HS • → H 2 S 2 or H 2 and S. [22] The disulfide can further react with HS • to make the disulfide radical HS–S • and H 2 S. [19]
The free radicals generated by this process engage in secondary reactions. For example, the hydroxyl is a powerful, non-selective oxidant. [6] Oxidation of an organic compound by Fenton's reagent is rapid and exothermic and results in the oxidation of contaminants to primarily carbon dioxide and water.
A trivalent group 14 radical (also known as a trivalent tetrel radical) is a molecule that contains a group 14 element (E = C, Si, Ge, Sn, Pb) with three bonds and a free radical, having the general formula of R 3 E•. Such compounds can be categorized into three different types, depending on the structure (or equivalently the orbital in which ...
A formula editor is a computer program that is used to typeset mathematical formulas and mathematical expressions. Formula editors typically serve two purposes: They allow word processing and publication of technical content either for print publication, or to generate raster images for web pages or screen presentations.
The formation of thiyl radicals in vivo primarily occurs through the action of various radicals on the amino acid cysteine incorporated into proteins. The rate of radical formation is highest with the OH · radical (k = 6.8 x 10 9 M −1 s −1) [3] and decreases through the H · radical (k = 6.8 x 10 9 M −1 s −1) [3] down to peroxyl radicals R-CHOO · (k = 4.2 x 10 3 M −1 s −1).
Heats of formations are intimately related to bond-dissociation energies and thus are important in understanding chemical structure and reactivity. [2] Furthermore, although the theory is old, it still is practically useful as one of the best group-contribution methods aside from computational methods such as molecular mechanics. However, the ...