Relations between bonding properties and stability for U and Am materials probed by RIXS

One of the fascinating questions in actinide chemistry is how the actinide bonding properties are related to their bond stability. We will discuss applications of core to core and valence band resonant inelastic X-ray scattering (CC/VB-RIXS) and quantum chemical computations and how these tools can probe bond covalency (cf. figure) of uranium (U) and americium (Am) [1-2]. All experiments are performed with the high resolution X-ray emission spectrometer installed at the ACT station (CAT-ACT beamline) at the KIT Light Source [6].
U M4 and M5 edge HR-XANES and VB-RIXS study combined with DFT and CASSCF calculations of U(VI), U(V) and U(IV) complexes with two different O2N3 ligands will be presented. Our results suggest that stabilization of U(V) requires strong bonding interactions of U(V) with the equatorial ligands, which can be of covalent or ionic nature. It will be illustrated that the binding of Fe(II) to uranyl oxygen results in the weakening the uranyl bond and in the redistribution of electron density leading to an increase of the bond covalency in the interaction of U(V) with the equatorial ligands [2].
Relations between bond stability and bonding properties will be also discussed for U and Am in U0.8Am0.2O2 [3] and U1-xPuxO2(+y) [4] nanoparticles, and for Am in AmVO3 and AmVO4 bulk compounds [5]. ... mehrThe oxidation states and chemical binding was probed by U M4 edge and Am M5 edge HR-XANES techniques.
References
[1] T. Vitova et al. Nat. Commun., 2017, 8, 16053.
[2} T. Vitova et al., Chem. Sci., 2022, 13 (37), 11038-1104.
[3] J.-F. Vigier et al., CrystEngComm, 2022, 24, 6338-6348.
[4] G. Kauric et al., Mater. Today. Adv., 2020, 8, 100105.
[5] J.-F. Vigier et al., Inorg. Chem., 2023, doi.org/10.1021/acs.inorgchem.3c00251.
[6] B. Schacherl et al., J. Synchrotron Radiat., 2022, 29 (1), 80-88.