Born-Bjerrum equation

It should be pointed out that the influence of anion solvation on equilibrium (13) cannot be explained by use of the Born-Bjerrum equations [Eqs. (1) and (2)]. Use of Eq. (2) generally gives negative AG values for the overall free-energy contribution to equilibrium (13) due to anion solvation. This means that formation of [CoCl4] should be particularly favorable in solvents with high dielectric constants such as water in contrast to the experimental results. 

Born (1) and later Bjerrum (2) developed a theoretical approach to ion-solvent interactions based on a rather simple electrostatic model. Ions are considered as rigid spheres of radius r and charge z in a solvent continuum of dielectric constant e. Changes in enthalpy AH av) and in free energy AG av), respectively, associated with the transfer of the gaseous ions into the solvent are represented by the following equations ... 

Bardeen potential, 340, 341 Bjerrum parameter, 112 Born-Green-Yvon equation, 22-24, 122... 

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