noun
- An ion of opposite charge that associates with a charged ion or molecule in solution to maintain electrical neutrality.
Usage: chemistry; technical
Examples
- In a sodium chloride solution, the chloride ion acts as a counterion to the sodium cation.
- The counterion atmosphere surrounding a charged polymer affects its behavior in solution.
- Counterions play an important role in the stability of colloidal suspensions.
- The charge of the counterion must balance the charge of the central ion.
- In electrolyte solutions, counterions migrate toward the electrode of opposite polarity.