We are independent & ad-supported. We may earn a commission for purchases made through our links.
Advertiser Disclosure
Our website is an independent, advertising-supported platform. We provide our content free of charge to our readers, and to keep it that way, we rely on revenue generated through advertisements and affiliate partnerships. This means that when you click on certain links on our site and make a purchase, we may earn a commission. Learn more.
How We Make Money
We sustain our operations through affiliate commissions and advertising. If you click on an affiliate link and make a purchase, we may receive a commission from the merchant at no additional cost to you. We also display advertisements on our website, which help generate revenue to support our work and keep our content free for readers. Our editorial team operates independently of our advertising and affiliate partnerships to ensure that our content remains unbiased and focused on providing you with the best information and recommendations based on thorough research and honest evaluations. To remain transparent, we’ve provided a list of our current affiliate partners here.
Chemistry

Our Promise to you

Founded in 2002, our company has been a trusted resource for readers seeking informative and engaging content. Our dedication to quality remains unwavering—and will never change. We follow a strict editorial policy, ensuring that our content is authored by highly qualified professionals and edited by subject matter experts. This guarantees that everything we publish is objective, accurate, and trustworthy.

Over the years, we've refined our approach to cover a wide range of topics, providing readers with reliable and practical advice to enhance their knowledge and skills. That's why millions of readers turn to us each year. Join us in celebrating the joy of learning, guided by standards you can trust.

What Is the Hydroxyl Radical?

By Vincent Summers
Updated: May 17, 2024
Views: 17,214
Share

Water is an electrically neutral molecule that can be formed through the combining of hydrogen ions and hydroxide ions, as in acid-base reactions. Written in chemists' shorthand, the reaction is H+ & OH- → H2O. Here, the lone hydrogen atom is actually an ion, carrying no negative electrons, and so bearing a positive charge, while the hydrogen-oxygen combine possesses two free electrons, giving it a negative charge. It is possible to produce another form of the hydrogen-oxygen combine, which carries only one free electron, not two. This is the electrically-neutral, yet chemically very reactive hydroxyl radical.

Oxygen is strongly electronegative, whereas hydrogen is electropositive. In addition, the hydrogen atom is quite small in comparison with the oxygen atom. It is the "electron-loving" oxygen atom, rather than the hydrogen atom, that carries the free electron. A population of free radicals decreases in number with time through attrition, as, for example, when two hydroxyl radicals unite to form one molecule of hydrogen peroxide. Conversely, the readily cleaved peroxides — especially organic peroxides with large appendages that tend to stretch those bonds, such as di-tert-butyl peroxide or benzoyl peroxide — are used as sources of free radicals in laboratory and commercial syntheses.

The hydroxyl radical is important, not only in the laboratory and in commerce, but in medicine, and in our atmosphere as well. Troposphere nitrogen oxide pollutants from motor vehicles and factories decompose to release excited atoms of oxygen, •O. These individual atoms, not to be confused with oxygen molecules, O2, combine with moisture in the air, converting into hydroxyl radicals, •OH. There are other sources of the hydroxyl radical, more commonly seen in other situations, including the reaction of ozone with doubly-bonded organic compounds called alkenes. In most instances occurring in nature, hydroxyl radicals are not considered desirable; such is the case in the field of health and medicine.

This is because the hydroxyl radical is a small and highly mobile, water-soluble form of free radical. In the human body free radicals are usually considered undesirable, and may be associated with illness and with aging. One enzymatic system of concern is the respiratory system, in which free radicals attack delicate body tissues. Atmospheric particulates — notably transition-metal-ions — have been recognized as hydroxyl radical formers in moist environments such as lung tissue, and lead to pulmonary disorders, including cancer. The hydroxyl radical has also been associated with chemical attack upon strands of DNA.

Share
WiseGeek is dedicated to providing accurate and trustworthy information. We carefully select reputable sources and employ a rigorous fact-checking process to maintain the highest standards. To learn more about our commitment to accuracy, read our editorial process.

Editors' Picks

Discussion Comments
Share
https://www.wisegeek.net/what-is-the-hydroxyl-radical.htm
Copy this link
WiseGeek, in your inbox

Our latest articles, guides, and more, delivered daily.

WiseGeek, in your inbox

Our latest articles, guides, and more, delivered daily.