Dissolution of Natural Oxides

Ligands and metal complexes present in aqueous systems in contact with natural oxides can affect their dissolution either by promoting or inhibiting it. For example, some metal—EDTA complexes react with Fe2C 3 and dissolve it, producing [Fe(III)EDTA]. Other minerals like Co(III)OOH and Mn(III)OOH reductively dissolve by oxidizing ligands and metal complexes. Dissolution rates can 

Soil components often retain complexes more strongly than they retain metal ions alone. For example, the general description of a surface reaction for the complex of a divalent metal (e.g., Pb2+) with a typical tetravalent ligand (e.g., EDTA4-) is depicted by 

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