Salle 5, Site Marcelin Berthelot
En libre accès, dans la limite des places disponibles


Oxide synthesis traces its roots back to BC. Their chemical and physical properties are largely dependent on cation selection. However, the 21st century has witnessed a surge in interest towards compounds composed of multiple anion species, called mixed-anion compounds [1]. In this seminar, recent research trends in mixed anion compounds will be reviewed from the viewpoints of synthesis, structure, and physical properties, with a particular focus on strain engineering – a pivotal concept applied to mixed anion compounds [2-6].
For example, H-anion conduction in BaH2 experiences a drastic reduction due to a phase transition to a low-symmetry phase at low temperatures, but through layer ordering (i.e., Ba2H3X (X = Cl, Br, I)), the halide layer acts as a protective layer, preventing symmetry lowering and allowing excellent H-anion conduction at low temperatures [2]. Medium-temperature nitridation of cubic perovskite SrVO3 bulk yields SrV(O,N)2.8 with periodic anion-vacancy layers in the 111 direction [4]. In epitaxial thin films, the direction and periodicity of the anion-vacancy layers can be tuned by applying the strain from the substrate. Anion-ordered perovskite EuVO2H, a ferromagnet with Tc = 10 K in bulk, exhibits inter-site charge transfer from the EuH layer to the VO2 layer VO2H thin films in compressively strained thin films, leading a fourfold increase in Tc as well as a giant perpendicular magnetic anisotropy [5]. A parallel concept is exemplified in the unique magnetism of Sr2NiO2Ag2Se2 that can be obtained under high pressure, where distinct compressibilities of multiple anions play a crucial role [6].
If time permits, the seminar will also touch upon recent finding in mechanochemical reactions [7].


[1] H. Kageyama et al. Nat. Commun. 9, 772 (2018).

[2] H. Ubukata et al. Sci. Adv. 7, eabf7883 (2021).

[3] Z Wei et al. Inorg. Chem. 62, 7993-8000 (2023).

[4] T. Yamamoto et al., Nat. Commun. 11, 5923 (2020).

[5] M. Namba et al., J. Am. Chem. Soc. 145, 21807 (2023).

[6] Y. Matsumoto et al, Angew. Chem. Int. Ed. 57, 756 (2019).

[7] Y. Sasahara et al, submitted.