Evidence for the formation of UO2(NO3)42− in an ionic liquid by EXAFS

Abstract

The complexation between uranium(vi) and nitrate ions in a hydrophobic ionic liquid (IL), namely [BMI][NO(3)] (BMI = 1-butyl-3-methylimidazolium(+)), is investigated by EXAFS spectroscopy. It was performed by dissolution of uranyl nitrate UO(2)(NO(3))(2)·6H(2)O or UO(2)(Tf(2)N)(2) (Tf(2)N = bis(trifluoromethylsulfonyl)imide (CF(3)SO(2))(2)N(-)). The formation of the complex UO(2)(NO(3))(4)(2-) is evidenced.

Exploring Actinide Materials Through Synchrotron Radiation Techniques

“…By taking into account of the coordination of water molecules introduced by dissolving UO 2 (NO 3 ) 2 ·6H 2 O in [BMIm][NO 3 ], the specific structure [UO 2 (η 2 ‐NO 3 ) 2 (η 1 ‐NO 3 )(H 2 O)] − was suggested. It was different from the results given by Gaillard et al. By dissolution of a low concentration of UO 2 (NO 3 ) 2 ·6H 2 O or UO 2 (Tf 2 N) 2 in [BMIm][NO 3 ] to keep the [NO 3 − ]/[UO 2 2+ ] ratio equal to 600, they found that the formed complex is UO 2 (NO 3 ) 4 2− and the 1 : 4 nitrato‐complex of uranyl was coordinated with two bidentate and two monodentate nitrate groups to uranyl, that was [UO 2 (η 2 ‐NO 3 ) 2 (η 1 ‐NO 3 ) 2 ] 2− .…”

Copper extraction using protic ionic liquids: Evidence of the Hofmeister effect

“…The observed anion:copper ratios do not necessarily indicate that the anions are coordinated with the copper, as previous work indicates that charged metal complexes are soluble in ILs [14,15] and uncoordinated ions can move into the IL phase in tandem with a charged metal complex to maintain electroneutrality [59,60]. As indicated in Table 3, all three mineral anions used in the present study coordinate relatively weakly with copper(II).…”

“…As a class, ILs are largely non-flammable and non-volatile, potentially simplifying their use in commercial environments [5][6][7]. A more fundamental advantage is that while ionic metal complexes are generally insoluble in organic phases, ILs are capable of solvating ionic as well as neutral metal complexes [14,15]. This amounts to the removal of a constraint on the coordination chemistry underlying extraction, offering researchers greater flexibility in process design.…”

Insights into the Mechanism of Extraction of Uranium (VI) from Nitric Acid Solution into an Ionic Liquid by using Tri‐n‐butyl phosphate

“…The presence of nitrate groups bound in ab identate fashion can be evidenced by the shoulder on the FT at R + DR = 2.3-2.4 (from Na toms) andt he peak at R + DR = 3.7 ( from Oa toms). Notably,t his kind of coordination of nitrates to uranium (VI) is predominant, even in ionic liquids, [41,42] and we did not consider am onodentate coordination of nitrates. The monodentate coordination of TBP molecules in the uranyl spherer esults in the presence of Pa toms at R + DR % 3.4 o nt he FT.W ed id not consider any bidentate coordination of TBP as it has never been reported, to our knowledge.…”