Iminodiacetic acid

Iminodiacetic acid, HN(CH₂CO₂H)₂, often abbreviated to IDA, is a dicarboxylic acid amine (the nitrogen atom forms a secondary amino group, not an imino group as the name suggests). The iminodiacetate anion can act as a tridentate ligand to form a metal complex with two, fused, five membered chelate rings. The proton on the nitrogen atom can be replaced by a carbon atom of a polymer to create an ion-exchange resin, such as chelex 100.