Etidronic acid monohydrate also known as 1-hydroxyethylidenediphosphonic acid (HEDP) is an organophosphonic acid that can be used to surface functionalize NaY molecular sieves. HEDP/NaY can be used as a catalyst for n-butyl acetate production via esterification.
It can be also employed as a chelating agent in the synthesis of metal-ligand complexes.