First Structural Characterization of a Protactinium(V) Single Oxo Bond in Aqueous Media

We report here the first structural characterization of Pa(V) adducts in concentrated sulfuric and hydrofluoric solutions. In sulfuric medium, X ray Absorption Spectroscopic data show that unlike the other early actinide elements as uranium or neptunium, protactinium doesn’t form a transdioxo cation but a monooxo adduct. In contrast, concentrated hydrofluoric medium precludes the formation of any oxo bond.