Ionic alkaline halide examples

Although the motion of protons does not lead to electrical conduction in the case of benzoic acid, electronic and even ionic conductivity can be found in other molecular crystals. A well-studied example of ionic conduction is a film of polyethylene oxide (PEO) which forms complex structures if one adds alkaline halides (AX). Its ionic conductivity compares with that of normal inorganic ionic conductors (log [cr (Q cm)] -2.5). Other polymers with EO-units show a similar behavior when they are doped with salts. Lithium batteries have been built with this type of... 

As the previous section showed, in a variety of examples severe enhancements of the ionic conductivity has been found and successfully attributed to space charge effects. Typical examples are silver halides or alkaline earth fluorides (see Section V.2.). How significantly these effects can be augmented by a particle size reduction, is demonstrated by the example of nano-crystalline CaF2.154 Epitaxial fluoride heterolayers prepared by molecular beam epitaxy not only show the thermodynamically demanded redistribution effect postulated above (see Section V.2.), they also highlight the mesoscopic situation in extremely thin films in which the electroneutral bulk has disappeared and an artificial ion conductor has been achieved (see Fig. 

Table 5.3 shows the experimental values of the cohesive energies and the semi-theoretical values, calculated for pure ionic and pure covalent bonding. Table 5.3 includes most of the available data on AB solids. The omitted examples, mostly alkali halides and alkaline-earth chalcogenides, show no unexpected features. 

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