20th International CODATA Conference (Times New Roman, 11pt)
Session: Computational informatics: integrating data science with materials modeling

Interplay of physicochemical and

structural features in ionic compounds and melts

Marcelle Gaune-Escard^a, Leszek Rycerz^b , Slobodan Gadzuric^a,c

^a Ecole Polytechnique, IUSTI CNRS 6595,

5 rue Enrico Fermi, 13453 Marseille Cedex 13, France

^b Wroclaw University of Technology, 50-370 Wroclaw, Poland

^c University of Novi Sad, 21000 Novi Sad, Serbia

Marcelle.Gaune-Escard@polytech.univ-mrs.fr

The phase diagrams of alkali-lanthanide (III) halide systems are of particular importance for nuclear separation and pyrochemical processes as also for the many other technologically important applications of lanthanides.

When combined to alkali halides (MX) , lanthanide(III) halides (LnX₃) form a variety of stoichiometric compounds. They differ in number and their stability range is quite various depending on the nature of both the alkali and lanthanide cations. However most systems include the M₃LnX₆ (3:1) congruently melting compound. In order to characterize this interplay between those compounds with congruently melting which apparently form from peritectic decomposition of others with a limited existence range, we have conducted a systematic evaluation of phase equilibrium in the MX-LnX₃ systems both from the information available in literature, which is sometimes quite fragmentary, and from our general research program on the physicochemical properties of lanthanides halides and their mixtures with alkali halides.

· A correlation between the topology of phase diagrams and the ionic potentials of lanthanide(III) and alkali cations was established. It is based on the exhaustive analysis of existing information on chloride systems. For the bromide and iodide lanthanide(III) systems, information was less but is building up through the experimental research being carried out. This information, some of it still unpublished, was used for the same purpose of correlating the main features in the corresponding phase diagrams, hilighting how this technique could make it possible to predict a priori the general features of still unexplored systems.

· In addition, another approach was performed, which used the informatics tools and expertise in informatics at Iowa State University (Prof. K. Rajan, krajan@iastate.edu) in conjunction with both the molten salt research and molten salt database in Marseille. Some preliminary results will be shown on how static data in databases, which are traditionally viewed as "static" documents and used in a "search and retrieval" mode, can be transformed by informatics and data mining tools into a dynamic dataset for analysis of the properties of the materials and for making predictions.

Keywords: Molten Salts, Lanthanide Halide, Compound, Research, Information System, Database,