Split-anion extraction is a new approach to the separation of mixtures of rare earths by solvent extraction. The rare-earth ions are extracted from a concentrated chloride aqueous phase to an organic phase, consisting of a water-immiscible thiocyanate or nitrate ionic liquid. This allows for efficient extraction of trivalent rare-earth ions from a chloride aqueous phase, without the need of using acidic extractants. The process is called split-anion extraction because the aqueous and organic phase contain different anions. Thiocyanate and nitrate anions have a strong affinity for the organic phase, while chloride anions have a strong affinity for the aqueous phase. In split-anion extraction, the source of complexing anions is the organic phase which allows for the use of chloride aqueous feed solutions and easy stripping of the rare earths from the loaded ionic liquid phase by water (instead of strong inorganic acids). The principle of the new extraction approach is described in detail for the extraction of rare earths from aqueous chloride solutions by the ionic liquids tricaprylmethylammonium thiocyanate and trihexyl(tetradecyl)phosphonium thiocyanate. Rare-earth and chloride concentrations can be varied to optimize the separation process. Separation factors between the end members of the lanthanide series (La-Lu) exceed the value of 200000.

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The proton-capture reaction 26 Si(p,γ ) 27 P was studied via Coulomb dissociation (CD) of 27 P at an incident energy of about 500 MeV/u. The three lowest-lying resonances in 27 P have been populated and their resonance strengths have been measured. In addition, a nonresonant direct-capture component was clearly identified and its astrophysical S factor measured. The experimental results are compared to Monte Carlo simulations of the CD process using a semiclassical model. Our thermonuclear reaction rates show good agreement with the rates from a recent compilation. With respect to the nuclear structure of 27 P we have found evidence for a negative-parity intruder state at 2.88-MeV excitation energy.

The behavior of plutonium still puzzles scientists 70 years after its discovery. There are several factors making the chemistry of plutonium interesting including its ability to keep several oxidation states. Another unique property is that the oxidation states +III, +IV, +V and +VI may exist simultaneously in solution. Another property plutonium shares with some other tetravalent metal ions is the ability to form stable polynuclear complexes or colloids. The structures of freshly prepared and five-year old plutonium(IV) colloids are compared with crystalline plutonium(IV) oxide using Pu L(3)-edge EXAFS. It was shown that as the plutonium colloids age they do in fact shrink in size, contrary to previous expectations. The aged colloidal particles are indeed very small with only 3-4 plutonium atoms, and with a structure very similar to solid plutonium(IV) oxide, but with somewhat shorter mean Pu-O bond and Pu···Pu distances indicating a partial oxidation. The very small size of the colloidal particles is further supported by the fact that they do not sediment on heavy ultra-centrifugation.