[en] The first dissociation constant of H₃PO₄ in acetonitrile solution (K₁⁰ = 1.75·10^-13) and the constant of formation of H(H₂PO₄)₂^- dimers (K_d⁰ = 8·10²) were determined by the method of pH-potentiometry. The complex formation of Am(III) in acetonitrile solutions containing 0.05-2.0 M H₃PO₄ was investigated by a spectrophotometric method; the stability constants of the complexes AmH₂PO₄²⁺ (β₁^III = 1.0·10¹²) and Am(H₂PO₄)₂⁺ (β₂^III = 4.3·10²⁴) were determined. The formal potentials of the couple Am^(IV)/Am^(III) in 0.3-1.9 M solutions of H₃PO₄ in acetonitrile were measured, and the stability constant of the phosphate complex of tetravalent americium Am(H₂PO₄)₃⁺ (β₃^IV = 2.5·10⁴⁶) was calculated according to the value of the shift of the potential relative to the standard

[en] Short note

[en] Oxidation potential of the Bksup((4))-Bksup((3)) pair is measured in H₃PO₄ solutions by the direct spectral electrochemical method. With phosphoric acid concentration increase from 3 up to 10 mol/l the value of oxidation potential decrease from 1.123 to 1.065 V (in respect to the normal hydrogen electrode)

[en] Short note

[en] The first constant of H₃PO₄ dissociation in acetonitrile solution (K₁⁰ = 1.75X10^-13) and the constant of H(H₂PO₄)₂^-(K_D⁰ = 8X10²) dimer formation were determined by pH-potentiometry method. Am(3) complexing in acetonitrile solutions, containing 0.05-2.0 mol/l H₃PO₄ was investigated by spectrophotometric method; stability constants of AmH₂PO₄²⁺(β₁³ = 1.0X10¹²) and Am(H₂PO₄)₂⁺(β₂³ = 4.3X10²⁴) complexes were determined. Formal potentials of Am⁽⁴⁾/Am⁽³⁾ pairs in 0.3-1.9 mol/l H₃PO₄ solutions in acetonitrile were measured; stability constants of phosphate complex of tetravalent americium Am(H₂PO₄)₃(β₃⁴ = 2.5X10⁴⁶) was calculated on the basis of the value of potential displacement with respect to the standard one

[en] Bk(3) complexing in acetonitrile solutions is studied using the spectrophotometric method. The constants of BkH₂PO₄²⁺ and Bk(H₂PO₄)₂⁺ complex stability are determined. The stability constant of the phosphate complex of tetravalent berkelium Bk(H₂PO₄)₃⁺ is calculated by the shift value of the formal potential of the Bk⁴⁺/Bk³⁺ pair in these solutions (relatively to the standard one). It is shown that when holding acetonitrile phosphate solutions of Bk(4) the latter is slowly reduced up to Bk(3) by the reaction of the zero order. The rate constant of the reduction reaction decreases with growth of H₃PO₄ concentration

[en] The authors measure the oxidation potential of the Bk(IV)-Bk(III) pair in H3PO4 solutions by a direct spectroelectrchemical method. When the phosphoric acid concentration is increased from 3 to 10 M, its value decreases from 1.123 to 1.065 V (with respect to a normal hydrogen electrode)

No abstract available

[en] Uranium extraction from the LiF-BeF₂ melt, containing 0.2 mol.% UF₄, by bismuth-lithium alloy at temperatures 600 to 655 deg has been studied. Linear dependence is obtained of the uranium distribution coefficient at a temperature of 650 deg on the lithium distribution coefficient, with the angular coefficient close to three. At 600 deg the Dsub(U) value reaches 2x10² at the lithium concentration in the alloy of about 1 at.%. Under these conditions separation of uranium from rare earth elements with separation factor 100-200 is possible

[en] Uranium extraction from LiF-BeF₂ melt containing 0.2 mole % UF₄ with bismuth-lithium alloy at 600-655⁰C was studied. A linear dependence of the uranium distribution coefficient at 650⁰C on the lithium distribution coefficient with a slope ratio of approx. 3.0 was noted. At 600⁰C the D/sub U/ value reached 2 x 10² when the lithium concentration in the alloy was about 1 at %. Under these conditions uranium can be separated from rare-earth elements with a separation factor of 100-200