A group of carcinogenic organic compounds, polychlorinated biphenyls (PCBs), is an example of a congener grouping. The number and locations of Cl groups can vary.

In chemistry, congeners are chemical substances "related to each other by origin, structure, or function".[1]

Common origin and structure

Any significant quantity of a polyhalogenated compound is by default a blend of multiple molecule types because each molecule forms independently, and chlorine and bromine do not strongly select which site(s) they bond to.

Similarly polychlorinated dibenzodioxins, polychlorinated dibenzofurans, polychlorinated terphenyls, polychlorinated naphthalene, polychloro phenoxy phenol, and polybrominated diphenyl ethers (PBDEs) (pentabromodiphenyl ether, octabromodiphenyl ether, decabromodiphenyl ether), etc. are also groups of congeners.

Common origin

Common structure

Main article: Structural analog

Congeners can refer to similar compounds that substitute other elements with similar valences, yielding molecules having similar structures. Examples:

Structural analogs are often isoelectronic.



  1. ^ IUPAC, Compendium of Chemical Terminology, 2nd ed. (the "Gold Book") (1997). Online corrected version: (2006–) "congener". doi:10.1351/goldbook.CT06819
  2. ^ 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" (PDF). Journal of Lipid Research. 44 (3): 567–575. doi:10.1194/jlr.m200356-jlr200. PMID 12562874.