Analytical reagent grade material can be used as primary standard after drying at 80o. Commercial grade material can be purified by crystallisation from water or by preparing a 10% aqueous solution at room temperature, then adding ethanol slowly until a slight permanent precipitate is formed, filtering, and adding an equal volume of ethanol. The precipitate is filtered off onto a sintered-glass funnel, is washed with acetone, followed by diethyl ether, and dried in air overnight to give the dihydrate. Drying at 80o for at least 24hours converts it to the anhydrous form. [Beilstein 4 IV 2451.]
ChEBI: A hydrate that is the dihydrate form of EDTA disodium salt.
White crystalline powder
Chelating agent; sequestering agent