[en] Investigations of the emission spectra of the neutral and singly ionized atoms of the heavy actinides have been in progress since the early 1960's in an association that used instrumentation and heavy element facilities from five laboratories. The level analyses have led to considerable understanding of the electronic structure of the elements Am to Es. When combined with the structure of the lighter actinides, a picture of the 5fⁿ7s² configuration increased stability as the series is ascended arises when the lowest level of known electronic configurations is plotted versus atomic number. A similar plot including the lanthanides shows how the actinides become more lanthanide in nature before the center of the series. Actinide chemical and physical properties have shown this before spectroscopic determination of the electronic configurations relative energies was accomplished. L. Brewer has used this knowledge to estimate relative energies of electronic configurations where spectroscopic values were not available

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[en] In the potentiometric titration of plutonium(III), it has been customary to take the equivalence point as the inflection point on a plot of potential vs. volume of titrant. It have not been, however, demonstrated, that the stoichiometric end point corresponds to the inflection point. Suggestions are made according to which these points may not correspond in the potentiometric titration of plutonium(III), as these titrations are ordinarily concluded in a period of time which is short compared to the time required for valence state rearrangement through disproportionation. (T.G.)

[en] Preliminary experiments indicated that a potentiostat could be used to control the Eh of soil slurries (kaolinite). Results so far indicate that the major amount of adsorption occurs in the first 15 minutes, that Pu(VI) adsorbs less than Pu(IV), that an increase in pH increases the adsorption, and that an increase in surface area and/or cation exchange capacity also increases the adsorption. 4 figs

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[en] Voronoj-Dirichlet (VD) polyhedrons were used to analyze the surrounding of Np(4-7) atoms by oxygen atoms in crystal structures of 55 compounds. It was established that the volume of Vd polyhedrons of neptunium atoms in coordination Np On polyhedrons didn't depend on their coordination number(CN) and was determined only by the valent state of atom. The unified linear dependence between values of solid angles of VD polyhedron faces of Np atoms and Np-O interatomic distances, corresponding to these faces, was established