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? Monosaccharide Definition and Functions Polysaccharide Definition and Functions What Is the Carboxyl Group in Chemistry? Learn What Methyl Means in Chemistry Review the Functional Groups in Organic Chemistry What Is an Amide? Definition and Examples What Is a Ligand in Chemistry Learn What an Acyl Group Is in Chemistry What Does Unsaturated Mean? Review Your Chemistry Concepts Find Chemistry Definitions From A to Z Chemistry Vocabulary Terms You Should Know What Is an Aryl Group in Chemistry? What Is a Carbonyl Group in Chemistry?