Anion conductors halides

A phenomenon of great practical relevance is the increase of ion conductivity by adding second surface active particles (a). The earliest example was LiI Al203, [11] later examples are silver, copper, and thallium halides which showed similar effects [4, 5]. Similar effects can also be observed for anion conductors examples (e.g., PbF2 Si02) (b) [4]. They all find their explanation in the concept of... 

DC and AC conductivity analysis on the Mg(II) and Pb(II) electrolytes were carried out using non-blocking (Mg or Pb) and blocking electrodes. The Mg(II) electrolytes showed no evidence of Mg(II) motion and appear to be virtually pure anion conductors. The Pb(II) electrolytes appeared to be good conductors of Pb(II) as well as halide ions. An initial estimate of the transport number of Pb(II) in PbBr. (PE0)2q is 0.6-0.7 at 140 C. We must caution that these transport number measurements are preliminary estimates. It is a major undertaking to measure definitive transport numbers, and that work is not yet begun. 

Solutions of non-electrolytes contain neutral molecules or atoms and are nonconductors. Solutions of electrolytes are good conductors due to the presence of anions and cations. The study of electrolytic solutions has shown that electrolytes may be divided into two classes ionophores and ionogens [134]. lonophores (like alkali halides) are ionic in the crystalline state and they exist only as ions in the fused state as well as in dilute solutions. Ionogens (like hydrogen halides) are substances with molecular crystal lattices which form ions in solution only if a suitable reaction occurs with the solvent. Therefore, according to Eq. (2-13), a clear distinction must be made between the ionization step, which produces ion pairs by heterolysis of a covalent bond in ionogens, and the dissociation process, which produces free ions from associated ions [137, 397, 398]. 

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