“…The orbital degeneracy,o nt he contrary,c an be relatively easily tuned through the metal atom oxidation state and the nature of the atoms bound to it. To achieve higher covalency,o ne could take advantage of using am etal atom in its highest oxidation states to increasei ts electronegativity,a nd a" ligand" atom that haslow electronegativity.Considering Uasa nexample, one needs to achieve its highest + 6o xidations tate while using low electronegative anions, such as sulfide or selenide, as counter-ions.A tf irst glance this appearst ob ear elatively straightforward approach, however,i ti si ndeed challenging to stabilizeu ranium in the + 6o xidation state in as ulfide environment owing to the tendency of sulfides to reduce uranium from + 6t o+ 4, [22,23] complicating the rational design of inorganic solid-state materials with covalentA n ÀQb onding( An = actinide,Q= chalcogenide).…”