Infrared Spectra and Structure of Uranyl and Transuranium (V) and (VI) Ions in Aqueous Perchloric Acid Solution

Abstract

Infrared spectra of aqueous solutions of U(VI), Np(VI), Pu(VI), and Am(VI) show conclusively that these ions exist as symmetrical and linear, or nearly linear, XO2++. The spectra of Np(V) and Am(V) show that they are probably XO2+ ions. Force constants and estimated distances are given for the X—O bonds. For the XO2++ series, the X—O force constant is expressed as a parabolic function of atomic number, with the maximum occurring at NpO2++. This is contrary to behavior expected if there were a regular contraction in ionic radii for the series XO2++.

In situ Spectroscopic Identification of Neptunium(V) Inner-Sphere Complexes on the Hematite–Water Interface

“…The υ 3 mode of the fully hydrated NpO 2 + species is observed at 820 cm −1 . 42 The same species is dominant under the prevailing sorption conditions, that is, 0.1 M NaCl, D 2 O, pH 8, N 2 (cf. Figure 3A).…”

“…This is due to a decrease of the NpO force constant as a result of complexation with Fe 2 O 3 units of the mineral phase in the equatorial plane. 29,42 The in situ vibrational data of Np(V) sorbed onto oxides of Ti, Si and Zn may serve as a reference, 29 as the experiments were performed under identical experimental conditions, that is, 0.1 M NaCl, D 2 O, pH 8, N 2 . A comparison of the data sets demonstrates that the frequency of the υ 3 of the sorbed Np(V) species is observed at ∼790 cm −1 irrespective of the sorbing surface.…”

Sorption of U(VI) at the TiO2–water interface: An in situ vibrational spectroscopic study

“…2 (upper panel). The m 3 (UO 2 ) mode of the fully hydrated UO 2þ 2 species, present in highly acidic aqueous solution, shows an absorption maximum at 961 cm -1 (Jones and Penneman, 1953;Quilès and Burneau, 2000). With increasing pH, hydrolysis reactions occur, monomeric and polymeric species are formed which, above all, strongly depend on the prevailing uranyl(VI) concentration (Grenthe et al, 1992;Guillaumont et al, 2003).…”

Viscometric Behavior of Concentrted Perchloric Acid

“…There are number of reports on the properties of perchloric acid in detail using spectroscopic, analytical and physical methods [1][2][3][4][5][6] . The dependence of viscosity of aqueous perchloric acid and chemical shifts of NMR as a function of concentration has been reported 7,8 .…”