Protactinium

Myasoedov, Β. F.; Kirby, H. W.; Тананаев, И. Г.

doi:10.1007/1-4020-3598-5_4

Cited by 21 publications

(24 citation statements)

References 225 publications

(356 reference statements)

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“…This study starts from the possible hydrated structures of Pa(V), and then examined the possible transformations from both kinetic and thermodynamic aspects. Consistent with the recent findings [20,23,24], the hydrated structures of [Pa(H 2 O) n ] 5+ (n = 1–12) are unstable, and [Pa=O(H 2 O) 6 ] 3+ are predominant in hydrous solution. The reason mainly relates to the high thermodynamic stability of protactinium complexes, and the high kinetic facility for the hydrogen transfer between the first-coordination-sphere water ligand and the second-coordination-sphere water ligands.…”

Section: Introductionsupporting

confidence: 89%

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Density Functional Theory Investigations on the Mechanism of Formation of Pa(V) Ion in Hydrous Solutions

Yang

Han

et al. 2019

Molecules

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Due to the enormous threat of protactinium to the environment and human health, its disposal and chemistry have long been important topics in nuclear science. [PaO(H2O)6]3+ is proposed as the predominant species in hydrous and acidic solutions, but little is known about its formation mechanism. In this study, density functional theory (DFT) calculations demonstrate a water coordination-proton transfer-water dissociation mechanism for the formation of PaO3+ in hydrous solutions. First, Pa(V) ion preferentially forms hydrated complexes with a coordination number of 10. Through hydrogen bonding, water molecules in the second coordination sphere easily capture two protons on the same coordinated H2O ligand to form [PaO(H2O)9]3+. Water dissociation then occurs to generate the final [PaO(H2O)6]3+, which is the thermodynamic product of Pa(V) in hydrous solutions.

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Section: Introductionsupporting

confidence: 89%

“…In recent years, the coordination structures of protactinium have been reported [14,15,16,17,18,19]. The element Pa mainly shows two possible valence states of Pa(IV) and Pa(V) in hydrous solutions [20]. Pa(IV) is only predominant in highly reductive systems, while Pa(V) is the main species in neutral/acidic hydrous solutions.…”

Section: Introductionmentioning

confidence: 99%

Density Functional Theory Investigations on the Mechanism of Formation of Pa(V) Ion in Hydrous Solutions

Yang

Han

et al. 2019

Molecules

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“…This behaviour may be related to the redox potentials of the substituting ions. The oxidation and reduction potentials of Pa(IV)/Pa(V) and Ti(IV)/Ti(III) are 0.10 and 0.19 V respectively [45,46]. The total potential (E…”

Section: Multiple M Xmentioning

confidence: 99%

Computational study of the substitution of early actinides and Ce into zirconolite

Tanti

Kaltsoyannis

2021

Journal of Nuclear Materials

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“…Its most stable oxidation state +5 corresponds to the formal electronic configuration 5 f 0 . Unlike all other light actinides at oxidation states +5 that form a linear trans-dioxo moiety, protactinium species are characterized most commonly by one single Pa–O oxo bond. − The occurrence of this short mono-oxo bond in Pa species depends on the medium. The mono-oxo bond has been observed in highly concentrated sulfuric and oxalic acid as PaO(SO 4 ) 3 3– and PaO(C 2 O 4 ) 3 3– , but it is absent in hydrofluoric acid, where the species PaF 7 2– has been identified. , In the system Pa(V)–HF, the breaking of the single oxo bond occurs after the coordination of Pa by 4 or 5 fluoride ions.…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic Study of the Complexation of Protactinium(V) with Diethylenetriaminepentaacetic Acid

et al. 2013

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The complex formation of protactinium(V) with DTPA was studied at different temperatures (25-50 °C) and ionic strengths (0.1-1 M) with the element at tracer scale. Irrespective of the temperature and ionic strength studied, only one neutral complex with (1:1) stoichiometry was identified from solvent extraction and capillary electrophoresis coupled to ICP-MS (CE-ICP-MS) experiments. Density Functional Theory (DFT) calculations revealed that two complexes can be considered: Pa(DTPA) and PaO(H2DTPA). The associated formation constants were determined from solvent extraction data at different ionic strengths and temperatures and then extrapolated to zero ionic strength by SIT methodology. These constants are valid, regardless of complex form, Pa(DTPA) or PaO(H2DTPA). The standard thermodynamic data determined with these extrapolated constants revealed a very stable complex formed energetically by an endothermic contribution which is counter balanced by a strong entropic contribution. Both, the positive enthalpy and entropy energy terms suggest the formation of an inner sphere complex.

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Protactinium

Cited by 21 publications

References 225 publications

Density Functional Theory Investigations on the Mechanism of Formation of Pa(V) Ion in Hydrous Solutions

Density Functional Theory Investigations on the Mechanism of Formation of Pa(V) Ion in Hydrous Solutions

Computational study of the substitution of early actinides and Ce into zirconolite

Thermodynamic Study of the Complexation of Protactinium(V) with Diethylenetriaminepentaacetic Acid

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