Functional groups are group of atoms with specific chemical properties that occur within organic molecules and sometimes denoted as "R". Functional groups are found along the carbon backbone of macromolecules can form chains or rings of carbon atoms. Functional groups can "functionalize" a compound by enabling it to adopt different physical and chemical properties. Types of common functional groups The table below summarizes some of the major functional groups in organic chemistry. (The functional groups are highlighted in red) Class of organic compounds Skeletal Structures of Compounds and functional groups (red) Name of Compounds Alkene 1-hexene Alkyne 2-butyne Alkyl halide Chloromethane Alcohol Methanol Thiol Ethanethiol Ether Diethyl ether (ethoxyethane) Sulfide Dimethyl sulfide (methylthiomethane) Epoxide Ethylene oxide (oxirane) This text is adapted from Openstax, Chemistry 2e, Section 20: Organic Chemistry.