Free-energy relationship

In physical organic chemistry, a free-energy relationship or linear Gibbs energy relation relates the logarithm of a reaction rate constant or equilibrium constant for one series of reactions with the logarithm of the rate or equilibrium constant for a related series of reactions. Establishing free-energy relationships helps understanding the reaction mechanism for a chemical reaction and makes it possible to predict reaction rates and equilibrium constants. The Brønsted catalysis equation describes the relationship between the ionization constant of a series of catalysts and the reaction rate constant for a reaction on which the catalyst operates. The Hammett equation predicts the equilibrium constant or reaction rate of a reaction from a substituent constant and a reaction type constant. The Edwards equation relates the nucleophilic power to polarisability and basicity.

External link

 * IUPAC Compendium of Chemical Terminology (The Gold Book)