Ionic partial

Whereas copper(I) thiazol-2-ylidene complexes are monocarbene and linear complexes that can form weak dimers in the solid state, the analogons gold(I) complexes could be synthesised as linear mono- or bis-carbene complexes. Since the metal requires a monoanionic ligand to balance its one positive charge, monocarbene complexes are normally neutral whereas the corresponding bis-carbene complexes are ionic. Partial protonation... 

Observed molar conductivities were analyzed by assuming the ion association (ion-pair formation) between the complex ions and the counter ions in the same manner as described previously. The closest distances of approach of ions (a) in the Robinson-Stokes conductivity equation and in the Debye-HUckel equation were taken as 6.8 and 7.3 A for chlorides and perchlorates of the tris(phen) complexes 6.6 and 7.1 A for those of the tris(bpy) complex, respectively, using the effective ionic radii of the complex ions, shown in T le 1, and those of Cl (1.81 A) and C104 (2.30A). The values of ref were estimated from the ionic partial molar volumes (f i°°) by use of Glueckauf equation. > ... 

Fig. 2.11.6. Ionic partial molal volumes in formamide, O formic acid, iV-methylpropionamide, and methanol, A vs. the corresponding volumes in water at 25°C.

The unusual mole fraction scale for the solution, with 5 x(H+,aq) = -68.2 J mol was used for the calculation of values of Astmc5 for the alkali metal and halide ions as well as Ag+ and CIO4 (Abraham et al. 1982). However, the choices of the value of 5 (H+, aq) and the mole fraction scale caused K+ to appear as a strue-ture making ion. This unacceptable result is corrected by adjustment to the molar scale with 5° (H+, aq) = - 22.2 J mol. Linear correlations of Astmc5 with the viscosity coefficients and with the NMR coefficients (Sect. 3.1.3) and also with the ionic partial molar volumes or their electrostricted volumes were noted by Abraham et al. (1982). 

Polarization measurements of this type are useful for the determination of transference numbers when the electronic partial conductivity (7 1 is small compared to the ionic partial conductivity a-jon. From the form of the curve of as a function of the applied voltage, information can be obtained regarding the nature of the electronic charge carriers [14]. 

The mobility of the electronic charge carriers is much greater than that of the ions. Therefore, despite the low concentration of electrons, when the oxygen partial pressure is very low the electronic partial conductivity will be of the order of the ionic partial conductivity. The following equation may then be written for the ionic transport number [29] ... 

The final bracketed expression in eq. (9-15) is obtained from the equilibrium condition of eq. (9-14), and from eq. (5-17) for and. The constant contains the ionic partial conductivity, the electrochemical mobility of the electrons, and the equilibrium constant of eq. (9-14). 

Tabulated are single-ion entropies of about 110 diatomic and polyatomic ions in water Gibbs energies, enthalpies, and entropies of hydration of monatomic ions at 25 C partial molar volumes of about 120 common ions at 25 C ionic partial molar heat capacities of ions Gibbs energies of transfer of inorganic electrolytes from HjO to 020 and calorimetrically determined enthalpies of solution of salts in H2O and 020. 

Reiss, I., Measurements of electronic and ionic partial conductivities in mixed conductors, with the use of blocking electrodes. Solid State Ionics, 44, 207-214 (1991). 

In Fig. 2, the basic principle of measurement of partial currents is shown. The current I consists of both electronic and ionic partial currents ... 

Zana and Yeager (1966) measured the individual or absolute ionic partial molar volumes of ions at room temperature using the ultrasonic vibration potentials and they could assign values for the V° of some ions with an error of 2 cm moT, while the uncertainty was higher for others. Thus, for at 22°C they found Vh+ = -5.4 cm mol". ... 

In order to avoid these non-thermodynamic assumptions in the assigning of ionic partial molar volume at infinite dilution, it is useful to define a conventional V ° for ions based on the value Vfl = 0 at all temperatures and pressures. 

In case T" were not available, even at ambient temperature and pressure, a correspondence principle was proposed by Shock and Helgeson (Shock and Helgeson, 1988), which correlates the standard ionic partial molar volume with the conventional standard ionic entropy. 

Table 2.2 Correspondence principle parameters for the standard ionic partial molar volume (Reproduced from Geochimica et Cosmochimica Acta, Calculation of the thermodynamic and transport properties of aqueous species at high pressures and temperatures with permission from Elsevier)...

Because of the charge equilibrium within the oxide, the electronic partial conductivity (electrons or holes) Oei and the ionic partial conductivity Oi are linked to the oxygen nonstoichiometry and, consequently, are two key parameters characterizing a MEEC. The methods developed for deconvoluting the ionic and electronic contributions to the total conductivity of a MIEC allow either the measurement of the partial conductivities, the diffusion coefficient of mobile defects or the transport numbers, either tei or hon- Only the methods involving a solid electrolyte cell are briefly described. Reviews papers can be referred [Heyne, 1982 Rickert, 1982 Riess, 1997 Weppner Huggins, 1978]. 

A related matter is the electrostriction suffered by these water molecules in the first solvation sphere. One of the ways to approach it is through determination of the partial molal volumes of the ions (with various assumptions we will not go into here). These ionic partial molal volumes can be split, using the semi-empirical Hepler equation (eq. 1), into a geometric... 

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