Ion

From EvoWiki

An Ion is an atom that has gained or lost one or more electrons, thus becoming electrically charged. Ions can be cations, which are positive, or anions, which are negative.

Ions can also be groups of covalently bonded atoms that have a net positive or negative charge. These polyatomic ions (not to be confused with free radicals), behave as individual charged particles and can form ionic bonds with other oppositely charged ions. Examples include the hydroxyl ion (OH^-), the ammonium ion (NH₄⁺), the carbonate ion (CO₃^-2) and the phosphate ion (PO₄^-3).

Ionic interactions are extremely important in the biochemistry of living organisms as well as the inorganic chemistry of rocks, minerals, oceans, and the atmosphere.