Uranium 5f Electron Behavior in MAX Phases: RIXS and HERFD-XANES Insights

We report the first synthesis of a U-containing MAX phase, an unexplored 5f-electron material with potential for nuclear-waste immobilization and resource reutilization. To elucidate uranium’s electronic structure, oxidation state, and bonding, we will propose high-resolution U M4-edge RIXS, U M4-edge HERFD-XANES, and Cr K-edge HERFD-XANES measurements. These data will provide the first spectroscopic characterization of an actinide MAX phase, revealing 5f/6d hybridization and U–Cr interactions, and guiding the development of stable actinide-contained materials.