Solvation numbers table

The values of hj for different ions are between 0 and 15 (see Table 7.2). As a rule it is found that the solvation number will be larger the smaller the true (crystal) radius of the ion. Hence, the overall (effective) sizes of different hydrated ions tend to become similar. This is why different ions in solution have similar values of mobilities or diffusion coefficients. The solvation numbers of cations (which are relatively small) are usually higher than those of anions. Yet for large cations, of the type of N(C4H9)4, the hydration number is zero. 

Here, Vs is the molar volume of the solvent and NA is the Avogadro constant. Some of the ionic solvation numbers obtained by this method are listed in Table 7.3. 

Table III. Primary Solvation Numbers. Comparison of Results from the Variation of B (vise.) with the Most Probable Values by Other Methods...

Total solvation numbers arise directly from the discussion following Passynski s Eq. (2.11), which requires measurements only of the compressibility (/S) of the solution (that of the solvent usually being known). Bockris and Salujaused this method in 1972 to obtain the total solvation numbers of both ions in a number of salts (Table 2.5). 

Bockris and Saluja applied these equations derived by Debye to a number of electrolytes and, using data that included information provided by Conway and by Zana and Yeager, calculated the difference of the solvation numbers of the ions of salts. The relevant parameters are given in Table 2.6. 

In the 1970s Bockris and Saluj a developed models incorporating and extending ideas proposed by Eley and Evans, Frank and Wen, and Bockris and Reddy. Three basic models of ionic hydration that differ from each other in the structure in the first coordination shell were examined. The features of these models are given in Table 2.16. The notations chosen for the models were lA, IB, 1C 2A, 2B, 2C and 3A, 3B, 3C, where 1, 2, and 3 refer to three basic hydration models, and A, B, and C refer to the subdivision of the model for the structure-broken (SB) region. These models are all defined in Table 2.16. A model due to Bockris and Reddy (model 3 in Table 2.16 and Fig. 2.37) recognizes the distinction between coordination number (CN) and solvation number (SN). 

The values of AS , of models A and C as well as their comparisons with experimental values are shown in Table 2.20 and in Figs. 2.43 and 2.44. It is necessary to reject model 1C because X-ray determinations of the CN indicate not 4, but numbers that vary from 6 to 8 as a function of the ion. The experimental results on solvation numbers have similar inference a sharp distinction between the solvation numbers of... 

Table P.4 lists measured dielectric constants at 25 °C for 1.0 M LiCl, NaCl, and KCl solutions, respectively. Calculate the percentage of water in the primary sheath and the total solvation number. Compare the results with those of the compressibility method (see problem 21) and comment on their reliability. 

Comparing the donor and acceptor numbers (Table 3) for the solvents listed in Table 4 reveals that they should solvate the anions almost equally and the cations differently. This also enables one to assume that the associate does not contain a cation as such, but generally has the anion structure. Comparing the location of absorption peaks for solvated electron e and the associate shows that in all media the associate does not contain in its composition a solvated electron as such and the properties of the solvated electron e are more sensitive to the nature of the solvent than those of the associate. 

The number of water molecules in the primary solvation shell of a bivalent cation as determined by diffraction methods is always between six and eight unless either cation size or ion-pair complexes intervene to. produce smaller values. Thus the primary shell can be either an octahedral or cubic complex. Table 2.3 shows how the solvation number and orientation of water molecules in a solvation complex can vary with electrolyte concentration. The variation in 0 with the molality of is striking. Evidently lone-pair interactions between a water molecule and this cation are favored in concentrated solutions but dipolar interactions are favored in dilute solutions. 

The experimental activity coefficients for LiCl, LiBr and Lil are given in Appendices 2.7.17B, 18B and 19B. An attempt has also been made to obtain solvation numbers for these salts using eqns. 2.6.43-2.6.46. The results of these calculations for several values of the penetration distance (cf. eqn. 2.6.46) are shown in Table 2.7.15. 

Table 3.6. Solvation numbers determined by various procedures, I... 

Solvation numbers obtained by different methods for a number of systems in various solvents are listed in Tables 3.6,3.7 and 3.8. It can be seen that many of the data are in agreement, but at least as many are contradictory. 

Table 3.8. Solvation numbers determined by means of mobility measurement...

Table 1 summarizes the different methods employed for the determination of ionic solvation numbers and what they measure. While each method has distinct advantages over others, it is often useful to use more than one method, e.g., the Jahn-Teller distorted structure of the hexa-hydrated copper(II) ion in water was revealed by XRD, but by neutron diffraction (ND) the elongated Cu—OH2 bonds at the axial position were not clearly visible. ... 

Table 47. Solvation Numbers in Crystalline Solvates Formed from 1 Molecule of Acceptor Halide...

Table 1. Apparent solvation numbers of li with EC, DEC, and DMC in some EC-based electrolyte solutions. Erom [ 48].

Thermodynamic properties of ions in nonaqueous solvents are described in terms of the transfer from water as the source solvent to nonaqueous solvents as the targets of this transfer. These properties include the standard molar Gibbs energies of transfer (Table 4.2), enthalpies of transfer (Table 4.3), entropies of transfer (Table 4.4) and heat capacities of transfer (Table 4.5) as well as the standard partial molar volumes (Table 4.6) and the solvation numbers of the ions in non-aqueous solvents (Table 4.10). The transfer properties together with the properties of the aqueous ions yield the corresponding properties of ions in the nonaqueous solvents. 

Table 3.1 Proton resonance shifts for various salts and individual ions in methanol, together with solvation numbers required to fit the correlation of Figure 3.7...

So far as I know, this is one of the best methods for estimating primary solvation numbers experimentally. In principle, neutron diffraction should be superior, although it gives somewhat different information, but it has not yet been used very successfully for systems such as those under consideration here. Using these procedures, solvation numbers for a range of probe solutes have been obtained (Table 3.2). It is noteworthy that the solvation number for water... 

Table 3.2 Solvation numbers for a range of solutes in water and in methanol, estimated from infrared spectroscopic data...

Table 6.2 The activation energy of diffusion coefficient and the solvation number...

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