Reciprocal ionic systems

Ternary ionic systems contain four kinds of ions, which can be constituted in three different ways (A+, B+, C+/X ), (A+ZX", Y , Z ), or (A" ", B+/X , Y ). The first two arrangements are additive ternary systems (the former one is a system with a common anion, the latter one is a system with a common cation), while the last one is a ternary reciprocal system. Having in mind the restriction of electro-neutrality, there are only three independent salt components, from which the solution could be built up. 

Figure 9. Reciprocal values of internal mobilities vs. molar volume in some binary systems (Li, K)Br, (Li, K)CI, (Na,K)OH, (Li, K)N03, and (Li, K)(S04)i/2 (Reprinted Rom M. Chemla and I. Okada, Ionic Mobilities of Monovalent Cations in Molten Salt Mixtures, Electrochim. Acta 35 1761-1776,Fig. 10, Copyright 1990 with permission from Elsevier Science.)...

A ternary reciprocal system is a system containing four components, but where these components are related through a reciprocal reaction. One example is the system LiCl-LiF-KCl-KF. Solid LiCl, LiF, KC1 and KF are highly ionic materials and take the rock salt crystal structure, in which the cations and anions are located on separate sub-lattices. It is therefore convenient to introduce ionic fractions (Xj) for each sub-lattice as discussed briefly in Section 3.1. The ionic fractions of the anions and cations are not independent since electron neutrality must be fulfilled ... 

A measurement of the ability of a buffer system to limit the change in pH of a solution upon the addition of an increment of strong base. ft is the reciprocal of the slope of the pH-neutralization curve. Consider the simple equilibrium, HA H+ -h A where K = [H+][A ]/ [HA] in which K is a practical dissociation constant determined under conditions of constant ionic strength. In such systems the practical pK is equal to the pH of solution when there are equal concentrations of the two buffer species. Since the total concentration of the two... 

Experimentally all the limiting cases of the recombination term are encountered in all systems investigated up to now. In solutions of tetraalkylammonium salts in benzene the reciprocal relaxation time is even dependent on the square of total concentration (but here the quadrupoles may be comparable in concentration with ion-pairs) which would indicated a preponderance of quintuple and triple ions in the ionic recombination. 

Stability constant — is the - equilibrium constant of formation of a - complex. The reciprocal quantity is called instability constant. Extensive compilations of various kinds of stability constants are available [i—iv]. Stability constants are reported for a given ionic strength (or extrapolated to zero ionic strength), and pH. In many cases, stability constants can be determined with the help of electrochemical techniques, e.g., -> chronopotentiometry, -> potentiometry, -> polarogra-phy, and - voltammetry, provided that the systems exhibit -> electrochemical reversibility, and some other prerequisites are fulfilled [v]. See also -> conditional equilibrium constants. 

In Equation 4.2, co is the frequency of the AC signal. Resistance in electrochemical systems includes ionic resistance, electronic resistance, charge-transfer resistance, and mass transfer resistance. The ionic resistance is sometimes expressed as ionic conductivity, using the unit of siemens per centimetre (S/cm), which is the reciprocal of the resistivity ... 

Our primary objective was to develop a computational technique which would correlate the ionization constant of a weak electrolyte (e.g., weak acid, ionic complexes) in water and the ionization constant of the same electrolyte in a mixed-aqueous solvent. Consideration of Equations 8, 22, and 28 suggested that plots of experimental pKa vs. some linear combination of the reciprocals of bulk dielectric constants of the two solvents might yield the desirable functions. However, an acceptable plot should have the following properties it should be continuous without any maximum or minimum the plot should include the pKa values of an acid for as many systems as possible and the plot should be preferably linear. The empirical equation that fits this plot would be the function sought. Furthermore, the function should be analogous to some theoretical model so that a physical interpretation of the ionization process is still possible. 

Figure 4.17 Total conductivity CSZ/AI2O3 multilayer systems at 575 °C as a function of the reciprocal thickness 1/d of the ionic conducting layers [274].

Buchner and coworkers established certain simple quantitative relationships in the action of salts on colloidal systems according to the Hofmeister rule. To a series of univalent anions they could even ascribe a numerical figure, termed lyotropic value , standing for the quantitative location of the ion concerned in the Hofmeister series. These figures were found to yield a linear relationship with the reciprocals of the ionic radii. ... 

Rochas and Rinaudo [569] constructed a phase diagram, where the logarithm of the total ionic concentration is plotted vs the reciprocal transition temperature (see Fig. 221). It characterizes the conformation and gelation of kappa carrageenan in KCl solutions. In domain I (relatively low concentration and high temperatureX only polymer coils are present in domain II (relatively low concentration and low temperature), the kappa carrageenan molecules are in the ordered, helical conformation, whereas in domain in (relatively high concentration and low temperature the system is in the (helical) gel state the boundary between domains II and III is not sharply known and for that reason is indicated by a wavy line. 

The units of electrolytic conductivity are m (reciprocal ohm m also called mho/m, mho m, or S m , where S is the siemen). The Systeme International d Unites (SI) unit is the S/m, but practical measurement units are usually in pS/cm. Electrolytic conductivity is also called specific conductance, not to be confused with conductance. The electrolytic conductivity of a solution is a measure of how well it carries a current, in this instance by ionic carriers rather than electron transfer, and it is an intrinsic property of the solution. A related property, the conductance, G, is also used and defined as G = l/R. The conductance is a property of the solution in a specific cell, at a specific temperature and concentration. The conductance depends on the cell in which the solution is measured the units of G are siemens (S). 

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