Significant Interactions between Uranium and Noble‐Gas Atoms: Coordination of the UO 2 + Cation by Ne, Ar, Kr, and Xe Atoms

A noble gas and an ignoble cation : A laser‐ablated uranium cation reacts with O 2 to give UO 2 + , which is found to form [UO 2 (Ng) n ] + (Ng=Ne, Ar, Kr, Xe) complexes on condensation with excess noble gas. Experiments with mixtures of noble gases lead to five new absorptions for the mixed [UO 2 + (Ng) x (Ng′) y ] complexes and show that the coordination number is five for Ng=Ar, Kr, and Xe (see picture).