Molten salts Temkin model

This principle serves as the basis for a number of models of fused salt systems. Perhaps the best known of these is the Temkin model, which uses the properties of an ordered lattice to predict thermodynamic quantities for the liquid state [79]. However, certain other models that have been less successful in making quantitative predictions for fused salts may be of interest for their conceptual value in understanding room temperature ionic liquids. The interested reader can find a discussion of the early application of these models in a review by Bloom and Bockris [71], though we caution that with the exception of hole theory (discussed in Section II.C) these models are not currently in widespread use. The development of a general theoretical model accurately describing the full range of phenomena associated with molten salts remains a challenge for the field. 

In mixtures of molten salts it is necessary to take into account the fact that the interaction forces are very strong and that the nearest neighbors of the cations are anions and the nearest neighbors of the anions are always cations. Therefore, random distributions of anions and cations cannot be conceived. On the basis of these considerations Temkin [18] proposed a model for ideal mixtures of molten salts which assumes the existence of two interlocking sublattices, one of cations and the other of anions. In the case of mixing of two salts, the cations mix on the cation sublattice and the anions mix on the anion sublattice. 

Owing to their polymeric character, silicate melts belong to the solutions of type II, which do not follow Raoult s law. The classic regular solution approach is not applicable, since the limiting laws are not obeyed. The Temkin s model of ideal ionic solution, which has been widely applied in molten salt systems, cannot be used, since the real anionic composition, owing to a broad polyanionic distribution, is not known a priori. 

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