Congener Definition and Examples

What Is a Congener?

The noble metals may be considered congeners.
The noble metals may be considered congeners. Tomihahndorf, Creative Commons License

In chemistry, the term "congener" can mean different things, depending on the context.

Congener Definition #1

A congener is a member of group of elements in the same periodic table group.
Example: Potassium and sodium are congeners of each other. Copper, gold, and silver are congeners.

Congener Definition #2

A congener can also refer to a class of compounds with similar structures and similar chemical properties.

Example: The class of chemicals called polychlorinated biphenyls (PCBs) have over 200 congeners.

Congener Definition #3

Congeners may refer to the oxidation states of a single element. For example, titanium dichloride (titanium 2+), titanium chloride (1+) and titanium tetrachloride (4+) are congeners.


  • Funari, Sérgio S.; Barceló, Francisca; Escribá, Pablo V. (2003). "Effects of oleic acid and its congeners, elaidic and stearic acids, on the structural properties of phosphatidylethanolamine membranes." Journal of Lipid Research. 44 (3): 567–575. doi:10.1194/jlr.m200356-jlr200
  • IUPAC (1997). Compendium of Chemical Terminology (2nd ed.) (the "Gold Book"). Compiled by A. D. McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford. ISBN 0-9678550-9-8. doi:10.1351/goldbook.
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Helmenstine, Anne Marie, Ph.D. "Congener Definition and Examples." ThoughtCo, Aug. 25, 2020, Helmenstine, Anne Marie, Ph.D. (2020, August 25). Congener Definition and Examples. Retrieved from Helmenstine, Anne Marie, Ph.D. "Congener Definition and Examples." ThoughtCo. (accessed March 29, 2023).