Electronic structure of cage-like compound UB 12 – Theory and XPS experiment

•Electronic structure of UB12 probed by X-ray photoemission (XPS) and ab initio.•Very good agreement between experimental and calculated XPS valence spectra.•Complex experimental core-level XPS spectrum with both 1-eV and 7-eV satellites.•Mixed-configuration behavior of U 5f states can be deduced.•At high pressure, no change in Fermi surface explains stability of cubic crystal structure.