[en] Because recent experience at the Savannah River Plant revealed the pseudo-hexagonal uranates Na2U2O7 and Na6U7O2 will react exothermically in the solid state with aluminum, a systematic thermal study of the aluminothermic reactions of the three crystal classes of uranates and their relationships was begun at the Savannah River Laboratory. This paper discusses that study

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[en] In a continuing study of the relative chemical reactivities of the higher fluorides of the d- and f-transition elements, oxidation-reduction reactions of plutonium hexafluoride with a selected series of non-metal fluorides in low oxidation states have been examined. This investigation has also included reactions with hydrogen and with various covalent chlorides and bromides. The results of this study have been correlated with those from previous investigations, and the reactivity of plutonium hexafluoride is considered in the light of plutonium as an f-transition element. Special techniques were developed for the study of compounds of this radioactive element, and a new procedure for the preparation of plutonium hexafluoride has been devised which requires apparatus very much simpler than previously reported. (author)

[en] The half-life of long-lived ²³⁶Np, due to α, β and electron-capture decay, was found to be 1.55 x 10⁵ yr. Of all decays, 88% populate excited states in ²³⁶U and 12% populate levels in ²³⁶Pu. Lifetimes measured by growth of the ground states of ²³⁶U and ²³⁶Pu agree with values from corresponding γ de-excitations in these daughter nuclei. Therefore, nearly all the electron-capture decays populate the 6⁺ level of the ground-state band in ²³⁶U. Similarly, essentially all the β^- decay populates an analogous 6⁺ level in ²³⁶Pu, which de-excites through a previously unreported transition of 158.3 keV. If a very week γ-ray at 894 keV can be ascribed to a level in ²³²U populated by β decay of ²³²Pa, its existence establishes a 0.2% α-branching decay in ²³⁶Np. (author)

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[en] The absorption spectra of uranium(+3) in 2 M HC10₄, of uranium(+3) chloro-complexes in anhydrous methyl alcohol and dimethylformamide, and of uranium(+3) thiocyanato-complexes in anhydrous methyl alcohol, were recorded in the range 4000 to 50,000 cm^-1. An intensity analysis of f-f transitions of the uranium(+3) spectra in 2 M HC10₄ and anhydrous methyl alcohol, has been made and is discussed with respect to the energy level assignment. Calculations of the 'free ion' energy levels, were carried out in order to determine which states of the configuration 5f³ are most sensitive to changes in the energy level parameters. (author)

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[en] The exchange of transition metal (M²⁺) ions from manganese through cobalt, nickel, copper to zinc with γ-zirconium phosphate was examined. By using acetate salts the hydrogen ion concentration is kept low enough to achieve high loadings. The fully loaded solids have the composition ZrM(PO₄)₂.4H₂O. Near quantitative uptakes are achieved at 100⁰C. The interlayer spacings change very little with loading indicating that γ-zirconium phosphate is able to accommodate cations and water molecules without appreciable increase in volume. The copper exchanged phase readily forms an acetylacetonate when shaken with 2,4-pentanedione. (author)

[en] Reaction of UCl₄ with 18-crown-6 in tetrahydrofuran yields (UCl₄)₃ (18-crown-6)₂ which on recrystallization in nitromethane, gives a partially oxidized and hydrolyzed product whose structure has been investigated by X-ray diffraction. The compound crystallizes in the orthorhombic system. The cell contains eight UCl₃⁺ cations each inserted within a crown molecule and four [UO₂Cl₃(OH)(H₂O)]^2-anions having a pentagonal bipyramidal structure. Four solvated nitromethane molecules are also present. The compound represents one of the very few examples in which uranium exists in two oxidation states, and the first example in which its insertion within a crown macrocycle has been proved by an X-ray diffraction study. (author)