Violation of electroneutrality

The violation of electroneutrality can be avoided by using a space-filling model. Such a model must fulfill the condition... 

Smith CP, White HS (1993) Theory of the voltammetric response of electrodes of submicron dimensions. Violation of electroneutrality in the presence of excess supporting electrolyte. Anal Chem 65 3343-3353... 

The region extending from the phase boundary out to about 3 nm is quite unlike the solution beyond. Generalizations valid elsewhere in the solution do not necessarily apply here. In this inner zone, the so-called double-layer region [9], we may encounter a violation of the electroneutrality condition (see Sect. 4.1) and large electric fields. Concentrations may be enhanced or depleted compared with the adjacent solution. 

We recognize that z < 0 hence, we have introduced the absolute value, z. Second, there is no possibility of separately determining either a+ or a. For, by definition, /i+ (3G/dn+)T p n that is, the determination of /i+ requires addition of just positive ions to the solution, while holding the concentration of anions fixed. However, this step cannot be carried out operationally because it involves a violation of the Law of Electroneutrality. Consequently, one should not attempt to deal with individual ionic activities rather, as Eq. (4.1.3b) shows, the ionic activities occur in such a manner that only their product or their logarithmic sum is involved. Third, since thermodynamic descriptions must be confined to measurable properties we may regard the quantity n + RT in a on the left of Eq. (4.1.3a) as an effective chemical potential that is to be used to represent the behavior of the electrolytes. On the other hand, one does not wish to ignore the ionic nature of the solution hence it is customary to set... 

The scattering of the macroion can be modelled in terms of a real excess electron density Aprod With a being the minimum approach of the macroion and the counterions, it follows that Ap(rc) = Aproci for all rc a. For rc a Ap(rc) is solely determined by the excess electron density of the counterions. Evidently, the integration in Eq. (6) must include all counterions, otherwise the condition of electroneutrality would be violated [17, 18],... 

The influence of ion size asymmetry on the properties of IL-vapor interfaces was investigated using soft primitive model MD simulations [106], The ion size asymmetry resulted in charge separation at the liquid-vapor interface and therefore in a local violation of the electroneutrality condition [106],... 

A literal interpretation of the equilibrium in [13] would be that, in order to keep electroneutrality in the resin phase, the sorption of a dicharged ion must be accompanied by desorption of two monocharged ions. At a first glance, eqn [17], therefore, seems to violate the principle of electroneutrality in the resin phase. However, the concentration for all types of ions in the external electrolyte is in equilibrium with the resin phase. In this particular case, this implies that the sorption of a dicharged ion will to a certain extent be accompanied by a sorption of the co-ion to the resin phase so that electroneutrality in the resin phase is maintained. 

Some authors have expressed concerns that bulk accumulation of reactive intermediates (and thus chemical capacitance) violates electroneutrality. ° However, it should be recalled that reduction (or oxidation) of a material not only involves depletion (or accumulation) of oxygen ions in the bulk but neutral combinations of oxygen ions and compensating electrons/holes which together may accumulate without violating electroneutrality. Indeed, no other mechanisms have yet been proposed which satisfac-... 

It has long been known that defect thermodynamics provides correct answers if the (local) equilibrium conditions between SE and chemical components of the crystal are correctly formulated, that is, if in addition to the conservation of chemical species the balances of sites and charges are properly taken into account. The correct use of these balances, however, is equivalent to the introduction of so-called building elements ( Bauelemente ) [W. Schottky (1958)]. These are properly defined in the next section and are the main content of it. It will be shown that these building units possess real thermodynamic potentials since they can be added to or removed from the crystal without violating structural and electroneutrality constraints, that is, without violating the site or charge balance of the crystal [see, for example, M. Martin et al. (1988)]. 

You should be aware of one important difference between the electrochemical potential and the chemical potential. The chemical potential describes the free energy of inserting one particle into a particular place or phase, subject to any appropriate constraint. Constraints are introduced explicitly. In contrast, the electrochemical potential always carries an implicit constraint with it overall electroneutrality must be obeyed. This is a very strong constraint. You can never insert a single ion in a volume of macroscopic dimensions because that would violate electroneutrality. You can insert only an electroneutral combination of ions. 

In addition to always giving a positive coion concentration, and, for small potentials, at the same level of accuracy as Eq. [79], Eqs. [84] and [85] give the product of the anion/cation concentrations for z z salts as unity, as it is with the nonlinear PB equation. (Of course, use of Eq. [85] violates electroneutrality.)... 

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