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The hydroxyl radical, Lewis structure shown, contains one unpaired electron. 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.
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]
Specific examples include stroke and heart attack. [ citation needed ] In general, the harmful effects of reactive oxygen species on the cell are the damage of DNA or RNA, oxidation of polyunsaturated fatty acids in lipids ( lipid peroxidation ), oxidation of amino acids in proteins, and oxidative deactivation of specific enzymes by oxidation ...
Radicals can propagate (k p) but also terminate (k t). However, persistent radicals (X), as stated above, cannot terminate with each other but only (reversibly) cross-couple with the growing species (k deact). Thus, every act of radical–radical termination is accompanied by the irreversible accumulation of X. Consequently, the concentration ...
In the case of chlorination, one of the chlorine atoms replaces a hydrogen atom. The reactions proceed via free-radical pathways, in which the halogen first dissociates into a two neutral radical atoms (homolytic fission). CH 4 + Cl 2 → CH 3 Cl + HCl CH 3 Cl + Cl 2 → CH 2 Cl 2 + HCl. all the way to CCl 4 (carbon tetrachloride) C 2 H 6 + Cl ...
Chemistry is the scientific study of the properties and behavior of matter. [1] It is a physical science within the natural sciences that studies the chemical elements that make up matter and compounds made of atoms, molecules and ions: their composition, structure, properties, behavior and the changes they undergo during reactions with other substances.
In this definition, there is a critical pressure and an associated critical density, and when nuclear matter (made of protons and neutrons) is compressed beyond this density, the protons and neutrons dissociate into quarks, yielding quark matter (probably strange matter). The narrower meaning is quark matter that is more stable than nuclear matter.
In chemistry, radical initiators are substances that can produce radical species under mild conditions and promote radical reactions. [1] These substances generally possess weak bonds—bonds that have small bond dissociation energies. Radical initiators are utilized in industrial processes such as polymer synthesis.