Ethylenediamine Acid (o-hydroxyphenylacetic), also derived from polycarboxylic acid, this chelating agent is used especially for its ability to form chelates with Fe due, above all, to its excellent stability in all pH ranges.

Because of the molecular structure of EDDHA, spatial orientation is especially important; being the possible ortho-ortho, ortho-para, and para-para.

Consequence of the different spatial orientation of each of these forms ortho-ortho is by far the one that offers the most stability in its combination with Fe, and therefore, greater potential for absorption by the plant. So much so that expresses the concentration o-o that in relation to the total percentage of Fe-EDDHA chelate has to have an accurate information of the potential of Fe contribution that the chelate has in the plant.