Functional Groups Definition and Examples

Chemistry Glossary Definition of Functional Groups

Benzyl acetate has an ester group (red).
Benzyl acetate has an ester group (red). Wikimedia Commons/Public Domain
By
Anne Marie Helmenstine, Ph.D.
Anne Marie Helmenstine, Ph.D.
Chemistry Expert
  • Ph.D., Biomedical Sciences, University of Tennessee at Knoxville
  • B.A., Physics and Mathematics, Hastings College
Dr. Helmenstine holds a Ph.D. in biomedical sciences and is a science writer, educator, and consultant. She has taught science courses at the high school, college, and graduate levels.
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Updated on July 03, 2019

Functional Groups Definition

A functional group or moiety is a specific group of atoms within a molecule that is responsible for characteristic chemical reactions of that molecule. No matter what size a molecule is, a functional group participates in chemical reactions in a predictable manner.

Functional groups link to the rest of the molecule via covalent bonds. The group may be neutral or charged.

Functional groups determine the reactions and properties of organic compounds.
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Common Functional Groups in Organic Chemistry
By Anne Marie Helmenstine, Ph.D.

Functional Group Examples:

Examples of common functional groups include alcohol (-OH), aldehyde (-COH), and nitrile (-CN).

Nomenclature

The naming convention for moieties describes whether it is saturated or unsaturated and whether it contains single, double, or triple bonds.

Class Formula Suffix Example
Single bond R• -yl Methyl group, Methyl radical
Double bond R: -ylidene Methylidene
Triple bond R⫶ -ylidyne Methylidyne
Carboxylic acyl radical R−C(=O)• -oyl Acetyl

Source

  • Brown, Theodore (2002). Chemistry : The Central Science. Upper Saddle River, NJ: Prentice Hall. p. 1001. ISBN 0130669970.
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Helmenstine, Anne Marie, Ph.D. "Functional Groups Definition and Examples." ThoughtCo, Aug. 26, 2020, thoughtco.com/definition-of-functional-groups-604473. Helmenstine, Anne Marie, Ph.D. (2020, August 26). Functional Groups Definition and Examples. Retrieved from https://www.thoughtco.com/definition-of-functional-groups-604473 Helmenstine, Anne Marie, Ph.D. "Functional Groups Definition and Examples." ThoughtCo. https://www.thoughtco.com/definition-of-functional-groups-604473 (accessed April 25, 2024).