Temperature-dependent structure-property relationships of sodalites

• Applicant: Dr. Lars Robben
• Subject Area: Mineralogy, Petrology and Geochemistry ; Solid State and Surface Chemistry, Material Synthesis
• Term: from 2021 to 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 459801229

Sodalites, belonging to the large structural family of zeolites, are microporous compounds and consist of a 3-dimensional network of metal atoms tetrahedrally coordinated with oxygen, forming the so-called sod cages. For naturally occurring sodalites, the framework is built-up by alternating Al3+ and Si4+ atoms. The cage fillings, consisting of cations (mostly Na+) as well as neutral molecules (eg. H2O) or anions (the latter are called templates), determine the size of the sodalite, because the framework adapts to the template-size by the tilt mechanism, a cooperative rotation of the framework tetrahedra. Both, the occurrence of phase transitions and the decomposition temperatures, depend on the framework-template combination in a manner not yet known. Therefore, the aim of the research project is to investigate the framework-template interactions in sodalites by temperature-dependent structural characterizations between 12 K and the decomposition temperature, whereby the framework and template composition are systematically varied. From this, structure-property relationships can be deduced, which will give a deeper insight into the nature of the bonding conditions in the cage.

• DFG Programme: Research Grants