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[en] Pyrrolidinedithiocarbaminate ions (PDTC^-) and Am(5) form a stable chelate. The optimum conditions of its formation and its composition (AmO₂⁺/PDTC^-=1/1) were established. The extraction of pyrrolidinedithiocarbaminates of Am(5), Am(3) and Am(6) was studied as a function of pH, concentration, the nature of the solvent and the presence of persulfate ions. It was shown that the indicator amounts of Am(5) may be separated from Am(3) and Am(6) in acetate buffer solution with pH 4.5-5.5 by coprecipitation of Am(5) pyrrolidinedithiocarbaminate or its extraction by a mixture of iso-pentanol and ethanol (3.5/1)

[en] Isotherms of extraction (26+-1 deg C) of macroscopic amounts of U(6) (O-300 g/l) and Pu(4) (0.5-100 g/l) from equilibrium aqueous solutions of nitric acid (0.15, 0.3, 0.5 and 1M) by 30% TBP solution in n-dodecane are reported. In weak HNO₃ solutions (0.15 and 0.3M) the effect of Pu ''self-salting-out'' is observed even at high concentrations of U(6). In 0.5M HNO₃ the effects of ''self-salting out'' and saturation of the extragent by the metal counterbalance each other and the coefficient of Pu distribution does not depend on its concentration in the aqueous phase. Uranium affects the behavior of Pu in the system in two ways. In weak HNO₃ solutions (0.15-0.3M) uranium in concentrations up to 15-20 g/l promotes the extraction of Pu, while in 0.5 and 1M acid solutions even minor amounts of U(6) dramatically suppress the extraction of Pu. The isotherms are described by empirical formulas with an accuracy of 5-10%

[en] Differential thermal, thermogravimetrical and X-ray phase analyses were used to establish the formation of Zn(UO₂)₃(MoO₄)₄x8H₂O (1) and Ni(UO₂)₃(MoO₄)₄x8H₂O (2) molibdatouranylates in the UO₂MoO₄-AMoO₄-H₂O systems where A is Zn or Ni. The unit cell parameters of isostructural rhombic (1) and (2) were determined; for (1) a=10.91, b=17.04, c=13.77 A; for (2) a=10.89, b=16.92, c=13.70 A, Z=4, spatial group A2₁22. Thermal decomposition of both compounds has been investigated. Partial dehydration of (1) results in monoclinic Zn(UO₂)₃(MoO₄)₄x4H₂O (3), whose unit cell parameters are: a=10.80, b=17.00, c=13.58 A, z=4, spatial group P2₁/c. The interplanar spacings for (1)-(3) are reported

[en] The stability of Pu(4) and Pu(6) in 6M nitric acid under 4.6 Wt/l alpha-radiation has been studied. Depending on the total concentration and on the ratio between Pu(6) and Pu(4) both the oxidation of Pu(4) and the reduction of Pu(6) were observed. Neither process is irreversible, so that an equilibrium between Pu(4) and Pu(6) is gradually established in the system. The equilibrium concentrations do not depend on whether equilibrium was reached via reduction or oxydation, but are essentially dependent on the overall concentration of Pu

[en] A survey of data obtained for the last 10 years concerning nuclear-physical and chemical properties of francium and promethium is presented. The development of radiometric technology and new methods for nuclear products separation make it possible to obtain new neutron-deficit isotopes, and to study in detail the schemes of decay of most radioisotopes Pm and Fr. Chemical-analytical properties are studied in two directions. 1) A great number of Pmsup((3)) compounds is synthesized; the data are obtained on their physical, crystallographic and thermodynamic parameters, as well as the stability constants of numerous complex compounds with inorganic and organic ligands. For the francium similar parameters are obtained by extrapolation methods. 2) New and more effective methods for the separation of francium and promethium from the accompanying elements are considered. Most promising are the chromatographic methods (ion-exchange, extraction, gaseous) πT

[en] A possibility is studied of using static sorption on the phosphonate of three-valent iron for defining a small content of plutonium in concentrated solutions of americium at the weight ratio Pu:Am < 0.01. A dependence is investigated of Am extraction in the sorbent on the ratio of solid to liquid at constant sorbent specimen, and dependence of Pu and Am washing on the number of sorbent washings. The sor tion on monoisopthylmethylphosphonate of three-valent iron is shown to combine a high degree of plutonium purifying from americium with a possibility of a high degree of plutonium concentration (4) at its extraction from the water phase. Sorption with a single washing can provide a quantitative estimation of plutonium-239 content up to 2x10^-11Ci (approximately 3p10^-10g) in a sample of 50 ml volume in the presence of americium containing more than 2x10^-6Ci (approximately 6x10^-7g), i.e. the limit of plutonium identification under the conditions is 6x10^-3 μg/l for americium not less than 12 μg/l

[en] Tritium-labelled polyisobuthylene was prepared in cationic polymerization of isobuthylene initiated by the molecular ions resulting from β-decay of tritium in twice tritiated isobuthane. The product possesses high specific activity

[en] To determine accurately an experimental value of a standard oxidation potential of two-valent fermium, a method has been applied for cocrystallization of two-valent fermium with strontium chloride from ethanol solutions in the presence of two-valent ytterbium as a reducer. During cocrystallization with a strontium chloride residue the fermium transits into the solid phase in the two-valent state only. The change in the ratio of three- and two-valent ytterbium in the solution leads to variation of the fermium cocrystallization coefficient on strontium chloride, which shows that two-valent fermium oxidation potential is close to the oxidation potential of two-valent ytterbium. As a result an equation has been proposed for estimating the standard oxidation potential E⁰ of the pair Fm²⁺/Fm³⁺ : Esub(Fmsup(2+)/Fmsup(3+))sup(0) = Esub(Ybsup(2+)/Ybsup(3+))sup(0)+-0.02 B

[en] Using the method of local optimization, numerical radial wave functions of 5f-, 6d- and 7s-orbitals of U, Np, Pu and Am are approximated by numerous series from the Slayter-type orbitals; 7s-, 6d- and 5-f functions are presented by series consisting of 8, 5, and 3 members, respectively. ''Reduced'' functions consisting of three Slayter members for each orbital are also obtained. The Slater-Condon integrals calculated with the functions obtained, agree well with the corresponding integrals calculated with numerical functions