Charge, ionic

It will be noted that hydration enthalpy decreases with increasing ionic radius and increases very sharply with increase in ionic charge, these results being what we should expect for an electrostate interaction between a charged ion and the dipole of a water molecule (p, 44). 

Mass Number, Atomic Number, Number of Atoms, and Ionic Charge. The mass number, atomic number, number of atoms, and ionic charge of an element are indicated by means of four indices placed around the symbol ... 

Ionic charge should be indicated by an Arabic superscript numeral preceding the plus or minus sign Mg2 +, PO -. 

Where it is not feasible to define an oxidation state for each individual member of a group, the overall oxidation level of the group is defined by a formal ionic charge to avoid the use of fractional oxidation states for example, Oy. 

Multiple Ions from One Base. Where more than one ion is derived from one base, the ionic charges are indicated in their names NjHJ, hydrazinium) 1-f) ion N2H5+, hydrazinium(2-l-) ion. 

The ionic strength can be estimated from the summation of the product molarity times ionic charge squared for all the ionic species present in the solution, i.e., I = 0.5(ciZi + C2Zi + + qzf). 

A connection between two solutions that allows the movement of current in the form of ionic charge. 

A high concentration of the fluorescent dye itself in a solvent or matrix causes concentration quenching. Rhodamine dyes exhibit appreciable concentration quenching above 1.0%. Yellow dyes, on the other hand, can be carried to 5 or even 10% in a suitable matrix before an excessive dulling effect, characteristic of this type of quenching, occurs. Dimerization of some dyes, particularly those with ionic charges on the molecules, can produce nonfluorescent species. 

Ion-exchange isotherms assume different shapes depending on the selectivity factor and the variations in with the level of exchange The rational selectivity coefficient includes the ionic charge and is given by... 

Elemental composition, ionic charge, and oxidation state are the dominant considerations in inorganic nomenclature. Coimectivity, ie, which atoms are linked by bonds to which other atoms, has not generally been considered to be important, and indeed, in some types of compounds, such as cluster compounds, it caimot be appHed unambiguously. However, when it is necessary to indicate coimectivity, itaUcized symbols for the connected atoms are used, as in trioxodinitrate(A/,A/), O2N—NO . The nomenclature that has been presented appHes to isolated molecules (or ions). Eor substances in the soHd state, which may have more than one crystal stmcture, with individual connectivities, two devices are used. The name of a mineral that exemplifies a particular crystal stmcture, eg, mtile or perovskite, may be appended. Alternatively, the crystal stmcture symmetry, eg, rhombic or triclinic, may be cited, or the stmcture may be stated in a phrase, eg, face-centered cubic. 

An important characteristic of plasma is that the free charges move in response to an electric field or charge, so as to neutralize or decrease its effect. Reduced to its smaUest components, the plasma electrons shield positive ionic charges from the rest of the plasma. The Debye length, given by the foUowing ... 

Cationic, anionic, and amphoteric surfactants derive thek water solubiUty from thek ionic charge, whereas the nonionic hydrophile derives its water solubihty from highly polar terminal hydroxyl groups. Cationic surfactants perform well in polar substrates like styrenics and polyurethane. Examples of cationic surfactants ate quaternary ammonium chlorides, quaternary ammonium methosulfates, and quaternary ammonium nitrates (see QuARTERNARY AMMONIUM compounds). Anionic surfactants work well in PVC and styrenics. Examples of anionic surfactants ate fatty phosphate esters and alkyl sulfonates. 

Chelates are often named merely as a complex, eg, cadmium complex with acetylacetone. A common practice ia the Hterature is to give the symbol of the central atom and an abbreviation for the ligand with or without an iadication of ionic charges, oxidation states, stmcture, or counterions, as ia the foUowiag Pb-EDTA, Cacit , Cu(en)2, Co(II)-(phen), [Cu(dipy)2]S04, [Ru(dipy)2(en)], and Na[Co(acac)2]. Ligand abbreviations are given ia Table 1. 

Conductometric Analysis Solutions of elec trolytes in ionizing solvents (e.g., water) conduct current when an electrical potential is applied across electrodes immersed in the solution. Conductance is a function of ion concentration, ionic charge, and ion mobility. Conductance measurements are ideally suited tor measurement of the concentration of a single strong elec trolyte in dilute solutions. At higher concentrations, conduc tance becomes a complex, nonlinear func tion of concentration requiring suitable calibration for quantitative measurements. 

The controhing effect of various ions can be expressed in terms of thermodynamic equhibria [Karger and DeVivo, Sep. Sci., 3, 393 1968)]. Similarities with ion exchange have been noted. The selectivity of counterionic adsorption increases with ionic charge and decreases with hydration number [Jorne and Rubin, Sep. Sci., 4, 313 (1969) and Kato and Nakamori, y. Chem. Eng. Japan, 9, 378 (1976)]. 

Membranes Ion-exchange membranes are highly swollen gels containing polymers with a fixed ionic charge. In the interstices of the polymer are mobile counterions. A schematic diagram of a cation-exchange membrane is depicted in Fig. 22-57. 

Processes in which solids play a rate-determining role have as their principal kinetic factors the existence of chemical potential gradients, and diffusive mass and heat transfer in materials with rigid structures. The atomic structures of the phases involved in any process and their thermodynamic stabilities have important effects on drese properties, since they result from tire distribution of electrons and ions during tire process. In metallic phases it is the diffusive and thermal capacities of the ion cores which are prevalent, the electrons determining the thermal conduction, whereas it is the ionic charge and the valencies of tire species involved in iron-metallic systems which are important in the diffusive and the electronic behaviour of these solids, especially in the case of variable valency ions, while the ions determine the rate of heat conduction. 

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