Abstract: The Sverjensky-Moiling linear free energy relationship was originally developed to correlate the Gibbs free energies of formation of an isostrutural family of solid phases to the thermodynamic properties of aqueous cations.In this report,we demonstrate that the similar relationship also exists between metal complexes and simple metal cations in aqueous solutions.We extend the Sverjensky-Molling relationship to predict the Gibbs free energies of formation or dissociation constants for a family of metal complexes with a given complexing ligand.The discrepancies between the predicted and experimental data are generally less than 1.5 kcal／mol(or one log unit for stability constants).The use of this linear free energy correlation Can significanfly enhance our ability to predict the speciation,mobility,and toxicity of heavy metals in natural environments.