Complexometric, also known as chelometric, is a term used to describe a chemical reaction in which a metal ion is surrounded by a complexing agent, or a chelating agent. This type of reaction is important in many different fields, including chemistry, biochemistry, and environmental science. There are several synonyms that can be used to describe complexometric reactions, including chelation, complexation, and metal-binding. Other terms that may be used to describe these reactions include ligand exchange, inorganic complexation, and coordination chemistry. Regardless of which term is used, the process involves the formation of a stable, soluble complex between a metal ion and a complexing agent.