Ethylenediaminetetraacetic acid (EDTA), also called EDTA acid, is an aminopolycarboxylic acid with the formula [CH₂N(CH₂CO₂H)₂]₂. This white, slightly water-soluble solid is widely used to bind to iron (Fe²⁺/Fe³⁺) and calcium ions (Ca²⁺), forming water-soluble complexes even at neutral pH. It is thus used to dissolve Fe- and Ca-containing scale as well as to deliver iron ions under conditions where its oxides are insoluble. EDTA is available as several salts, notably disodium EDTA, sodium calcium edetate, and tetrasodium EDTA, but these all function similarly.

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Ethylenediaminetetraacetic acid disodium salt dihydrate is a chemical compound used as a powerful chelating agent for metal ions. The “99% AR” designation indicates a 99% purity of the substance, with “AR” standing for Analytical Reagent grade, meaning it is a high-purity grade suitable for chemical analysis and research. It works by binding to metal cations, preventing their activity in biological systems and products.