Alkali Metals in Focus: Investigations on the Structural Chemistry of Alkali Metal Thallides

• Applicant: Dr. Stefanie Gärtner
• Subject Area: Solid State and Surface Chemistry, Material Synthesis
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 468336522

The scope of the applied project is to highlight the structural chemistry of the system alkali metal thallium, while special attention is drawn at the role of the different alkali metals among structure formation. Compounds consisting of alkali metal and thallium show a very versatile structural chemistry. The amount of alkali metal does not readily suggest the formed thallium sublattice. In fact, one can find transitions between different type structures in dependence of the more electropositive element involved. Especially for the heavier homologues of the first group of the PSE in combination with thallium, the number of characterized compounds is very limited. Within the scope of the applied project alkali metal thallides will be synthezied via high temperature synthesis and characterized by state-of-the art x-ray diffraction techniques. Here, in particular different alkali metals will be employed simultaneously in order to gain a deeper understanding for their effect on structure formation. The combination of different group 1 elements and thallium has been investigated only for selected compounds yet. These investigations are limited to the lighter alkali metals sodium and potassium, even though they yielded very promising results including the so far unknown Tl9 clusters. Systematic investigations are missing, especially for the heavier alkali metals. These compounds naturally possess very high absorption coefficients for x-rays, which for a long time was equitable to the physical frontier of the method of structure determination for these element combinations. Nowadays, for these compounds, which were formerly assumed to behave rather as a primary beam stop, very good data sets can be realized due to highly resolving detectors and intensive x-ray sources. Almost 90 years after the first discovery of the textbook-known sodium thallide structure by E. Zintl, these enhanced techniques allow for new insights into the structural chemistry of the element thallium in dependence of the involved alkali metal.The acquirement of knowledge on the structural chemistry of the system alkali metal - thallium means a clear desideratum, which we wish to satisfy by means of state-of –the-art x-ray diffraction techniques.

• DFG Programme: Research Grants