Complex sulfate of uranium and potassium

Peretrukhin, V.F.; Крот, Н. Н.; Gel'man, A.D.

doi:10.1007/bf00911881

Cited by 6 publications

(31 citation statements)

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“…36,37,53,54,58,59,79 We have confirmed that the spontaneous reduction of freshly prepared Pu(VII) is rapid, t 1/2 = 3.7 h (1.3 × 10 4 s) at 25°C, in the absence of O 3 under continuous O 2 saturation in the single solution examined here. This half-life is in exact agreement with an independent report.…”

Section: +supporting

confidence: 83%

“…32−35 The situation is less clear for Pu(VII), at least in part because its propensity to oxidize water has made it difficult to study. 36,37 Chemical evidence suggests that it follows behavior similar to Np(VII), forming the [Pu VII O 4 (OH) 2 ] 3− moiety. 38 In contrast, XANES (X-ray absorption near-edge structure) data obtained from a solution in which Pu(VI) was oxidized electrochemically in concentrated NaOH, are consistent with a dioxo complex, exhibiting very slightly reduced Pu−O bond lengths (0.01−0.02 Å) when compared with those from the initial solution.…”

Section: ■ Introductionmentioning

confidence: 98%

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Preparation, Stability, and Structural Characterization of Plutonium(VII) in Alkaline Aqueous Solution

et al. 2012

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A freshly prepared solution of Pu(VI) in 2 M NaOH was oxidized to Pu(VII), via ozonolysis, while simultaneously collecting X-ray absorption spectra. Analyses of the XANES (X-ray absorption near edge structure) and EXAFS (extended X-ray absorption fine structure) data, acquired throughout the in situ experiments, show a dioxo coordination environment for Pu(VI), PuO(2)(2+), typical for it and the hexavalent actinyl species of U and Np, and its evolution into a tetraoxo-coordination environment for Pu(VII), PuO(4)(-), like that known for Np(VII). The EXAFS data provide average Pu-O distances of 1.79(1) and 1.88(1) Å, respectively. The second coordination shells, also fit as O atoms, provide Pu-O distances of 2.29-2.32 Å that are independent of the Pu oxidation state. The coordination numbers for the distant O atoms in sums with those for the nearest O atoms are consistent with 6-O environments for both Pu(VI) and Pu(VII) ions in accordance with their previously proposed speciation as [Pu(VI)O(2)(OH)(4)](2-) and [Pu(VII)O(4)(OH)(2)](3-), respectively. This solution speciation accounts precisely for the Pu(VI) and Pu(VII) coordination environments reported in various solid state structures. The Pu(VII) tetraoxo-dihydroxo anion was found to have a half-life of 3.7 h. Its instability is attributed to spontaneous reduction to Pu(VI) and not to a measurable extent of disproportionation. We found no direct evidence for Pu(VIII) in the X-ray data and, furthermore, the stoichiometry of the oxidation of Cr(III) by Pu is consistent with that expected for a valence-pure Pu(VII) preparation by ozonation and, in turn, stoichiometrically equivalent to the established Np(VII)/Cr(III) redox reaction.

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Section: +supporting

confidence: 83%

Section: ■ Introductionmentioning

confidence: 98%

Preparation, Stability, and Structural Characterization of Plutonium(VII) in Alkaline Aqueous Solution

et al. 2012

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“…The chemical properties of the actinides in acidic media have been more extensively and more thoroughly investigated *Author for correspondence (E-mail: daniel.meyer@cea.fr). than in basic media, no doubt because of their low solubility in basic media [1][2][3][4][5][6][7][8][9]. A previously unknown facet of americium chemistry was recently discovered, however: i.e.…”

Section: Introductionmentioning

confidence: 99%

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confidence: 99%

Selective dissolution of Am in basic media in the presence of ferricyanide ions: a mechanistic and structural study on Am(V) and Am(VI) compounds

Meyer¹,

Fouchard²,

Simoni³

et al. 2002

Radiochimica Acta

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Americium exhibits a soluble form in aqueous alkaline media in the presence of ferricyanide ions (Fe(CN) 6 3− ), which is not the case for the other transplutonium elements (TPE). This soluble Am compound can be obtained by addition of a concentrated basic solution of ferricyanide ions on a trivalent americium hydroxide precipitate. Thus, this technique enables a complete and rapid extraction of americium through its soluble form in alkaline solutions whereas under these conditions, other TPE and the lanthanides remain in the solid state as trivalent hydroxides. In the case of dissolution involving large amounts of americium, the formation of the soluble americium species is followed by the appearance of a reddish precipitate in the basic solution. Dissolution of the reddish solid in NaOH or NaOH/Fe(CN) 6 3− media demonstrated the existence of a media-dependent solubility of the precipitate, and therefore the existence of at least two forms of soluble Am.Spectroscopic (UV-visible, EXAFS-XANES, Raman) and electrochemical investigations were carried out on the different forms of americium to determine the nature of the compounds. This study points out that the reddish solid Am compound is probably a Am(V) hydroxide: Na 2 AmO 2 (OH) 3 ·3H 2 O while the other Am species is a mixed americyl-ferricyanide complex. This work demonstrates that this dissolution of Am(III) solid compound is much more complex than a simple oxidation by the ferricyanide ions. The existence of a molecular interaction between Am(V)O 2 + and ferricyanide ions is highly probable. This selective dissolution of americium by a basic ferricyanide solution can be used to define a separation process of Am from lanthanides and other transplutonium elements in the field of high level liquid waste treatment.

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“…In the literature, various methods such as coulometry [1,2] extraction [3], extraction chromatography [4], paper chromatography [5,6,7], column partition chromatography [8], ion exchange [9,10], precipitation and coprecipitation [3,10,11,12] and absorption [13,14] are described for the quantitative determination of coexisting neptunium oxidation states. All these methods imply the addition of reagents which change the chemical composition.…”

Section: Introductionmentioning

confidence: 99%

Simultaneous Quantitative Determination of the Various Oxidation States of Neptunium at Low Concentrations by Spectrophotometry

Gauthier¹,

Ilmstädter²,

Lieser³

1983

Radiochimica Acta

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The direct and simultaneous spectrophotometric determination of Np(IV), Np(V) and Np(VI) at low concentrations (> 10" 7 M) in nitric acid (up to 3 M) and in the presence of uranyl nitrate (up to 1 M) without addition of a complexing agent is described. The splitting of the absorption peak of Np(V) at 981 nm due to the formation of a 1 : 1 binuclear complex with U(VI) and the overlap of this peak with the absorption peak of Np(IV) at 978 nm are taken into account. Limits for quantitative determination of Np(IV), Np(V) and Np(VI) are of the order of 10" 6 , 10" 7 and 10" 6 M, respectively.

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Complex sulfate of uranium and potassium

Cited by 6 publications

References 0 publications

Preparation, Stability, and Structural Characterization of Plutonium(VII) in Alkaline Aqueous Solution

Preparation, Stability, and Structural Characterization of Plutonium(VII) in Alkaline Aqueous Solution

Selective dissolution of Am in basic media in the presence of ferricyanide ions: a mechanistic and structural study on Am(V) and Am(VI) compounds

Simultaneous Quantitative Determination of the Various Oxidation States of Neptunium at Low Concentrations by Spectrophotometry

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