Energy ion solvation

This fomuila does not include the charge-dipole interaction between reactants A and B. The correlation between measured rate constants in different solvents and their dielectric parameters in general is of a similar quality as illustrated for neutral reactants. This is not, however, due to the approximate nature of the Bom model itself which, in spite of its simplicity, leads to remarkably accurate values of ion solvation energies, if the ionic radii can be reliably estimated [15],... 

The reliability of the experimental A / MX) values was checked for systems containing nitrobenzene, nitromethane, and 1,2-dichlo-roethane as organic solvent by comparing the differences in these values for various pairs of salts with the differences in the Galvani (i.e.,distribution) potemtials, A cp MX) for the same pairs. The differences should be the same. The A cp or Afip data can be used to estimate ion solvation energies in a water-saturated solvent. ... 

Much attention has been directed since olden times towards ion solvation, which is a key concept for understanding various chemical processes with electrolyte solutions. In 1920, a theoretical equation of ion solvation energy (AG ) was first proposed by Born [1], who considered the ion as a hard sphere of a given radius (r) immersed in a continuous medium of constant permittivity (e), and then defined AG as the electrostatic energy for charging the ion up to ze (z, the charge number of the ion e, the elementary charge) ... 

The purpose of this chapter is to discuss mainly recent development in the theory of ion solvation energy. Because we allowed much space for introducing our new, non-... 

The modification by method 2 is more acceptable. Although several types of modifications have been reported, Abraham and Liszi [15] proposed one of the simplest and well-known modifications. Figure 2(b) shows the proposed one-layer model. In this model, an ion of radius r and charge ze is surrounded by a local solvent layer of thickness b — r) and dielectric constant ej, immersed in the bulk solvent of dielectric constant ),. The thickness (b — r) of the solvent layer is taken as the solvent radius, and its dielectric constant ej is supposed to become considerably lower than that of the bulk solvent owing to dielectric saturation. The electrostatic term of the ion solvation energy is then given by... 

On the assumption that = 2, the theoretical values of the ion solvation energy were shown to agree well with the experimental values for univalent cations and anions in various solvents (e.g., 1,1- and 1,2-dichloroethane, tetrahydrofuran, 1,2-dimethoxyethane, ammonia, acetone, acetonitrile, nitromethane, 1-propanol, ethanol, methanol, and water). Abraham et al. [16,17] proposed an extended model in which the local solvent layer was further divided into two layers of different dielectric constants. The nonlocal electrostatic theory [9,11,12] was also presented, in which the permittivity of a medium was assumed to change continuously with the electric field around an ion. Combined with the above-mentioned Uhlig formula, it was successfully employed to elucidate the ion transfer energy at the nitrobenzene-water and 1,2-dichloroethane-water interfaces. 

When the ion is much larger than the solvent, it can be assumed that the number (N) of solvent molecules adjacent to the ion is proportional to the surface area of the ion N = An p (where p is the number of solvent molecules per unit surface area of the ion). Accordingly, the contribution of the CT interaction to the ion solvation energy AG is given by... 

AGsol = i (y"-s) also holds well for ion solvation energies.13 Clearly, there... 

The use of electrostatic potentials, defined in the context of DFT, for the calculation of ion solvation energies has been reviewed. It has been shown that physically meaningful ionic radii may be obtained from this methodology. In spite of the fact that the electrostatic potentials for cations and anions display a quite different functional dependence with the radial variable, we have shown that it is still possible in both cases to build up a procedure consistent with the Bom model of ion solvation. 

Labowsky, M. Fenn, J.B. de la Mora, J.F. A Continuum Model for Ion Evaporation From a Drop Effect of Curvature and Charge on Ion Solvation Energy. Anal. Chim. Acta 2000,406, 105-118. 

There is a relationship A = ,Resolvation energies, in contrast to the fact that, in the solid state, electrical conductivity is obtained only with graphite, for which IP = EA = 4.34 eV. 

The model used for ion solvation energies since the work of Bernal and Fowler16 has considered simple electrostatic interactions between the ion and the permanent and induced charges on solvent molecules, plus a term for estimating the work involved in importing the ionic charge... 

The term A is related to the solvent density and molecular weight and to the free volumes of the ions and the ion-pair [59]. Fjoi is the difference between the molar ion-pair solvation energy and the free ion solvation energy. The theory does not predict a simple linearity of In with lie. Actually solvent effects other than that due to the relative permittivity of the solvent are easily predicted, since the macroscopic e is only a rudimentary description of the real attenuation of the ionic interactions due... 

In the second approach to the electrochemical determination of the ion solvation energy, a cell without a liquid junction is used. Such a cell consists of an electrode formed by the ions to be studied, and as a reference a solvent-independent reference electrode (SIRE) ... 

Single Ion Solvation Energies in Organic Solvents, — AG2oiv(ion)/kcal mol , at 25°C (molal scale)... 

In a similar way, the ion solvation energy (4.71) is calculated with account for the supercell periodicity as... 

Table 12.6 Single ion solvation energies in water, -AGsoiv/U morat 25°C [10]...

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