The formation of a coordination complex in between edta and ferric ions is called Ferrous EDTA. Iron is always in the ferric form in contact with aerated natural water. Edta is a chelating agent that has high affinity for ferric ions. [Fe(edta)(H2O)] is the principle complex near neutral pH. The trihydrate Na[Fe(edta)(H2O)].H2O. and more such cations can be crystallized with the [Fe(edta)(H2O)]Ã¢Ëâ anion. Yellow brown is the color of the salts. Iron chelate finds application in agriculture, horticulture and ornamental horticulture, as a plant tonic and for the purpose of treating chlorosis and feeding ericaceous plants. Ferrous EdTA has been proven beneficial in controlling some broadleaf weeds in lawns.