Speaker: Dr. Jonas Jacobs, Martin-Luther-Universität Halle-Wittenberg.

Topic:
Ruddlesden-Popper (RP) compounds (general formula (AX)(ABX₃)_n) are a current hot topic in materials research as they possess a high flexibility regarding their anion composition. This makes them an ideal platform for experiments which aim on tuning of physical properties for example by substitution of oxygen by fluorine (O^2-/2F^–) yielding the corresponding oxyfluorides. The targeted synthesis of such new RP-oxyfluorides is a challenging task as most of them are metastable and therefore suitable synthesis conditions are mostly found by numerous trial and error experiments. Understanding the formation chemistry of oxyfluorides is therefore crucial for optimizing reaction conditions and gaining access to new metastable products.

For the fluorination of La₂NiO₄ with PVDF laboratory in situ XRD experiments were established as highly useful tool for obtaining optimized reaction conditions. These investigations were additionally combined with in situ neutron powder diffraction to reveal a complex fluorination pathway involving four reaction intermediates. This talk is about the application of such in situ XRD fluorination experiments for the preparation of new oxyfluorides (La₂NiO_2.5F₃,¹ La₂CoO₃F₃, La₂(Ni,Cu)O₃F₂^2,3,4) as well as their less stable reaction intermediates.

[1] J. Jacobs et al., Inorg. Chem. 60, 2021, 13646. [2] J. Jacobs et al., Inorg. Chem. 61, 2022, 17202. [3] J. Jacobs et al., Inorg. Chem. 63, 2024, 6075. [4] J. Jacobs et al., Inorg. Chem. 63, 2024, 11317.

Series: STOE User Talks 2024/2025

Time: 43 min.