Electrical neutrality principle

This determination of the coordination number of the ion is predicated on the electrical neutrality principle given earlier (see page 19). This principle is also called the electrostatic valence principle and is part of Pauling s second rule In a stable ionic structure the valence of each anion, with changed sign, is exactly or nearly equal to the sum of the strengths of the electrostatic bonds to it from the adjacent cations. (Pauling, 1960)... 

In the p modification the chloride ions are also arranged in hexagonal close-packing, but with one titanium layer alternating with one chloride layer to form inorganic macromolecules (TiCls) (Fig. 27). It follows from the electrical neutrality principle that three chloride vacancies must exist per chain. Furthermore, since only chloride ions at the end of a chain can be attached to one titanium ion, chloride vacancies must be located there. 

Crevice corrosion of copper alloys is similar in principle to that of stainless steels, but a differential metal ion concentration cell (Figure 53.4(b)) is set up in place of the differential oxygen concentration cell. The copper in the crevice is corroded, forming Cu ions. These diffuse out of the crevice, to maintain overall electrical neutrality, and are oxidized to Cu ions. These are strongly oxidizing and constitute the cathodic agent, being reduced to Cu ions at the cathodic site outside the crevice. Acidification of the crevice solution does not occur in this system. 

To predict the formula of an ionic compound, you need to know the charges of the two ions involved. Then you can apply the principle of electrical neutrality, which requires that the total positive charge of the cations in the formula must equal the total negative charge of the anions. Consider, for example, the ionic compound calcium chloride. The ions present are Ca2+ and Cl-. For the compound to be electrically neutral, there must be two Cl- ions for every Ca2+ ion. The formula of calcium chloride must be CaCl indicating that the simplest ratio of Cl- to Ca2+ ions is 2 1. 

You know die charge of die complex and those of the ligands. To find the formulas of the coordination compounds, apply the principle of electrical neutrality. 

Electrical neutrality The principle that, in any compound, the total positive charge must equal the total negative charge, 38... 

If the species is neutral, its chemical potential p% can be varied by changing its concentration and hence its activity ay. dpt — RT d nat. In this case the determination of the surface excesses offers no difficulty in principle. However, if a species is charged, its concentration cannot be varied independently from that of a counterion, since the solution must be electrically neutral. To be specific, we consider the case of a 1-1 electrolyte composed of monovalent ions A and D+. The electro capillary equation then takes the form ... 

Sulfur has four unique characteristics related to its occurrence and chemistry in soil. As sulfate, it is one of the principle counterions that keep the soil electrically neutral. Soil receives constant additions of sulfur through volcanic activity around the world and industrial pollution, usually in the form of acid rain. This means that soils usually have sufficient sulfur for plant growth. Lastly, plants can take and use sulfur dioxide from the air as a source of sulfur for growth [22,38],... 

This term is zero since the solution as whole must be electrically neutral (the principle of electrical neutrality). Thus, Eq. (2.16) is reduced to... 

One equation takes note of charge balance, a principle based on the fact that the solution is electrically neutral overall the concentration of cations must equal that of anions. Because there is only one type of cation, H30+, the concentration of HsO+ ions must equal the sum of the concentrations of the two types of anions, Cl and OH-. The charge balance relation [H30+] = [Cl-] + [OH-] then tells us that... 

Pauling s principle of local electrical neutrality Charges are neutralized locally in crystals. Lewis s principle of zero formal charges Charges are neutralized locally in molecules. 

First, the amount of metallic orbital per atom in a metal is given by the ratio of M+ and M° to M+, M°, and M- since M+ and M° require an extra orbital for unsynchronized resonance to occur, whereas M- does not have this possibility according to the principle of electrical neutrality [45]. Moreover, the numbers of M+ and M must be equal and their sum equal to half of M+ + 2 M° + M. ... 

Generally, a crystal is electrically neutral. This implies that the crystal should have an equal number of positive and negative charges. Thus, when oppositely charged ions come together to form a neutral crystal structure, each ion coordinates with as many ions of opposite charge as the size permits. This coordination principle dictates both electrical neutrality of the crystal structure and compact packing of the atoms within the structure. 

The same principles can be applied to many other cases. For example, consider the compound formed between aluminum and oxygen. Because aluminum has the configuration [Ne]3s23p1, it must lose three electrons to form the Al3+ ion and thus achieve the neon configuration. Therefore, the Al3+ and 02 ions form in this case. Since the compound must be electrically neutral, there must be three 02 ions for every two Al3+ ions, and the compound has the empirical formula AI2O3. 

Table 8.3 lists a few representative standard electrode potentials (or reduction potentials). Figure 8.6 exemplifies the principle of an electrochemical cell. The hydrogen electrode is made up of a B-electrode (which does not participate directly in the reaction), which is covered by H2(g), which acts as a redox partner [H2(g) = 2H +2e ]. Pt acts as a catalyst for the reaction between H and H2(g) and acquires a potential characteristic of this reaction. The salt bridge between the two cells contains a concentrated solution of salt (such as KCl) and allows ionic species to diffuse into and out of the half-cells this permits each half-cell to remain electrically neutral. 

If solutions on two sides of a membrane contain different concentrations of ions that cannot freely move through the membrane (e.g., proteins), distribution of the diffusible ions (e.g., electrolytes) at the steady state wfll be unequal, but the product of the concentrations of ions in one compartment is equal to the product of ions in the other compartment (Gibbs-Donnan law). Also the law of electrical neutrality is obeyed for both compartments. An example of the uneven distribution of an ion in two compartments with different protein content (nondiffusible ions) is the concentration of chloride ions in plasma and CSF. As a result of the increased selectivity of the blood-brain barrier against proteins, Cr ions are -15% higher in CSF to estabflsh electrical and osmotic equflibrium. Calculations that demonstrate these principles can be found in the first edition of this textbook (pp. 1225-1227). ... 

The overriding principle in many extractions of aqueous samples is for the analyte molecules to be as near neutral as possible by adjusting the pH of the sample matrix. This guiding principle applies to most liquid—liquid and reverse-phase solid-phase extractions. If a compound cannot be made electrically neutral through pH adjustment, then an alternate approach could be considered. A compound such as a zwitterion, which cannot be made electrically neutral could be isolated from the matrix using an approach which is insensitive to the ionization state of the molecule, such as direct injection, protein precipitation, microdialysis, or ultrafiltration. 

A second practical problem arose from the realization that the molecules of this paper can, in principle, occur in nature and the laboratory in their electronic ground states, in vibrationally and electronically excited states, and as ions. In this paper we report only electronic ground state properties of electrically neutral molecules. 

The fundamental principle governing all aspects of electrolyte solutions is that electrical neutrality must be maintained throughout the solution (see Section 2.12). 

Even though, as a whole, the system is electrically neutral, repulsion between the particles occurs. Upon addition of indifferent (= non adsorbing) electrolyte (e.g. a salt), the double layers become less active and, as a consequence, the particles can now approach each other more closely before repulsion sets in. If enough salt is added, the particles may eventually come so close that van-der-Waals attraction binds them together. This is, in principle, the explanation of the sensitivity of colloids and suspensions to salts and may, in other environments, be used to destroy stable colloids or suspensions and cause flocculation. 

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