Formation-decomposition equilibrium of the NpO·UO complex in chloride melts.

Autor: Barbanel’, Yu., Dushin, R., Kolin, V., Kotlin, V., Mashirov, L., Nekhoroshkov, S.
Předmět:
Zdroj: Radiochemistry; May2007, Vol. 49 Issue 3, p237-240, 4p, 2 Graphs
Abstrakt: The absorption spectra of the NpO (5 f 2) ion were examined in the region of the 3 H 53 H 4 magnetic dipole transition (1530–1760 nm) for series of melts with the UO concentration varied in the opposite directions: (1) NaCl-2CsCl eutectic melt with growing additions of the Cs2UO2Cl4 complex salt and (2) Cs2UO2Cl4 melt with growing additions of the NaCl-2CsCl mixture. Measurements of the integrated intensities of the bands belonging to the NpO·UO complex and unbound NpO throughout the UO concentration range examined (up to 4.4 M in neat Cs2UO2Cl4 melt) and processing of the data obtained in terms of the mass action law showed that the formation-decomposition reaction of the cation-cation complex can be described adequately only using the equation of reaction in the form NpO2Cl + UO2Cl ⇆ {Cl4ONpO⋯UO2Cl3}4− = Cl (with the equilibrium constant of 1.3±0.1). Thus, the formation of the cationcation complex should be treated as replacement of chloride ion in the equatorial plane of uranyl(VI) by neptunyl(V), rather than as simple addition of UO to NpO. The reverse reaction, decomposition of the cation-cation complex, consists essentially in replacement of neptunyl(V) by chloride ion. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index