Science, Tech, Math › Science Functional Groups Definition and Examples Chemistry Glossary Definition of Functional Groups Share Flipboard Email Print Benzyl acetate has an ester group (red). Wikimedia Commons/Public Domain Science Chemistry Chemical Laws Basics Molecules Periodic Table Projects & Experiments Scientific Method Biochemistry Physical Chemistry Medical Chemistry Chemistry In Everyday Life Famous Chemists Activities for Kids Abbreviations & Acronyms Biology Physics Geology Astronomy Weather & Climate by Anne Marie Helmenstine, Ph.D. 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. Updated 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 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. Continue Reading Review of Organic Functional Groups What Is a Sol? What Is a Moiety in Chemistry? Learn What an Acyl Group Is in Chemistry Chemistry Vocabulary Terms You Should Know What Is a Carbonyl Group in Chemistry? What Is the Carboxyl Group in Chemistry? Find out What a Trans Isomer Is What Is an Aryl Group in Chemistry? Review the Functional Groups in Organic Chemistry What Should You Know About Lipids, and Why Do They Matter? What Is a Substitution Reaction in Chemistry? What Does Unsaturated Mean? Review Your Chemistry Concepts What Is the Alkoxy Group in Chemistry? Topics Covered in 11th Grade Chemistry What Is a Multiple Bond in Chemistry?