An organic chemical that forms multiple bonds with metal ions is known as what type of agent?

The most appropriate term for an organic chemical that forms multiple bonds with metal ions is a chelating agent. These agents have the ability to bind metal ions through multiple coordination sites, usually resulting in the formation of cyclic structures known as chelates. This unique bonding capability allows them to effectively sequester metals, making them less available for unwanted reactions in various applications, including those in pool water chemistry.

While sequestering agents and complexing agents are indeed related concepts, they do not specifically encapsulate the definition of a chelating agent. Sequestering agents often bind to metal ions through single attachment points, but they do not necessarily form multiple bonds or cyclic structures. Complexing agents can refer to a broad range of chemicals that can form complexes with metal ions, but this term might not always imply the multiple bond characteristic that defines chelating agents.

Thus, while it is technically correct to say all these agents share a common purpose related to metal ion interaction, the best term for the description provided is a chelating agent, as it highlights the specificity of forming multiple bonds with metal ions.