California Code, Food and Agricultural Code (Formerly Agricultural Code) - FAC § 14524

(a) “Natural organic complexes” means organic by-products of the wood pulp and other industries, such as the lignin sulfonates and polyflavinoids, that form complexes with metallic secondary nutrients and micronutrients. “Natural organic complexes” do not include synthetic chelates in that natural organic complex, generally known as the natural organic chelates which are polymers, for which the nature of the metallic bonding is not known.

(b) “Inorganic complexes” include inorganic cations which form coordinate chemical bonds with other inorganic cations, anions, or neutral molecules, such as where metal-ammonia complexes of zinc or ammonia are coordinately bonded to the metal cation, and which usually reacts differently than the metal alone in solutions, but dissociates in soil and reacts as the uncomplexed cation.