Congener (chemistry)

Example of a congener: the number and locations of Cl groups can vary

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

Common origin and structure

• Polychlorinated biphenyls (PCBs) are a family of 209 congeners. Polybrominated diphenyl ethers (PBDEs) are another family of 209 congeners. Any significant quantity of PCBs or PBDEs is by default a blend of multiple molecule types because each molecule forms independently, and chlorine does not strongly select which site(s) it bonds to.

Common origin

• Congener (alcohol), substances other than alcohol (desirable or undesirable) also produced during fermentation.
• Congeners of oleic acids can modify cell membrane behavior, protecting against tumors or having effects on blood pressure.^[2]

Common structure

• Congeners can refer to similar compounds that substitute other elements with similar valences, yielding molecules having similar structures. Sodium chloride and potassium chloride may be considered congeners. Also potassium chloride and potassium fluoride.

Other

• Congeners refer to the various oxidation states of a given element in a compound. For example, titanium(II) chloride (titanium dichloride), titanium(III) chloride (titanium trichloride), and titanium(IV) chloride (titanium tetrachloride) may be considered congeners.
• Congeners can refer to other elements in the same group in the periodic table. For example, congeners of the Group 11 element copper are silver and gold.

References

1. IUPAC, Compendium of Chemical Terminology, 2nd ed. (the "Gold Book") (1997). Online corrected version:  (2006–) "congener".
2. http://www.desy.de/~sergio/Funari-JLR-2003.pdf Effects of oleic acid and its congeners, elaidic and stearic acids, on the structural properties of phosphatidylethanolamine membranes