Citrates, which are released by plant roots and by some microorganisms, can solubilize iron compounds in the soil.

[4] Ferric citrate is used in medicine to regulate the blood levels of iron in patients with chronic kidney disease on dialysis.

It acts by forming an insoluble compound with phosphate present in the diet and thus minimizing its uptake by the digestive system.

In the present of excess citrate anions, the iron forms negatively charged complexes like [Fe(C6H4O7)2]5− and [Fe9O(C6H4O7)8(H2O)3]7−.

[3][4] The Fe3+ ion in ferric citrate (as in many iron(III) carboxylates) is reduced by exposure to light,[8] especially blue and ultraviolet, to Fe2+ (ferrous) ion with concomitant oxidation of the carboxyl group adjacent to the hydroxyl, yielding carbon dioxide and acetonedicarboxylate: where -R represents the group -CH2CO−2.