The EDTA Molecule

EDTA or ethylenediaminetetraacetic acid is a novel molecule for complexing metal ions.  It is a polyprotic acid containing four carboxylic acid groups (acidic hydrogens arered) and two amine groups with lone pair electrons (green dots).  The classic structural formula is given below.   EDTA is synthesized on an industrial scale from ethylenediamine, formaldehyde, and a source of cyanide (HCN or NaCN).   Click here for the industrial reactions to open in a new window.  On a worldwide basis over 100,000 metric tons are produced annually