Solving the Hydration Structure of the Heaviest Actinide Aqua Ion Known: The Californium(III) Case

Galbis, Elsa; Hernández-Cobos, Jorge; Auwer, Christophe Den; Naour, C. Le; Guillaumont, Dominique; Simoni, E.; Pappalardo, Rafael R.; Marcos, Enrique Sánchez

doi:10.1002/ange.200906129

Cited by 27 publications

(38 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It has been described that the metal coordination sphere in the hydrates is a tricapped trigonal prism for the entire Ln 3+ series [35] and for some of the An 3+ series (Pu to Cm). [36] Very recently, the coordination sphere of Cf III has also been discussed in more detail, both in acid medium by EXAFS and molecular dynamics [37] and in the solid state for the hydrate system. [38] The structure of the hydrate confirms the stability of the TTP polyhedron throughout the series from U to Cf (Bk not reported).…”

Section: Discussionmentioning

confidence: 99%

Local Structure in Americium and Californium Hexacyanoferrates – Comparison with Their Lanthanide Analogues

et al. 2011

Self Cite

View full text Add to dashboard Cite

Metal hexacyanoferrates are well known molecular solids for a large variety of cations, although very little has been described for actinide adducts. Two new members of actinide(III) hexacyanoferrates were synthesized with the cations americium and californium. They were structurally characterized by infrared and X-ray absorption spectroscopy. Combined EXAFS data at the iron K edge and actinide L3 edge provide evidence for a three-dimensional model for these two new compounds. Structural data in terms of bond lengths were compared to those reported for the parent lanthanide(III) compounds, neodymium and gadolinium hexacyanoferrates, respectively: the americium compound with KNdIIIFeII(CN)6*4H2O and the californium compound with KGdIIIFeII(CN)6*3.5H2O and KGdIIIFeII(CN)6*3H2O. This comparison between actinide and lanthanide homologues has been carried out on the basis of ionic radii considerations. The americium and neodymium environments appear to be very similar and are arranged in a tricapped trigonal prism polyhedron of coordination number 9 (CN: 9), in which the americium atom is bonded to six nitrogen atoms and to three water molecules. For the californium adduct, a similar comparison and bond length and angle values derived fromEXAFS studies suggest that the californium cation sits in a bicapped trigonal prism (CN: 8) as in KGdIIIFeII(CN)6*3H2O. This arrangement differs from that in the structure of KGdIIIFeII(CN)6*3.5H2O, in which the gadolinium atom is surrounded by 9 atoms. This is one of the rare pieces of information revealed by EXAFS spectroscopy for americium and californium in comparison to lanthanide atoms in molecular solid compounds. A discussion on the decrease in bond length and coordination number from americium to californium is also provided, on the basis of crystallographic results reported in the literature for actinide(III) and lanthanide(III) hydrate series

show abstract

Section: Discussionmentioning

confidence: 99%

Local Structure in Americium and Californium Hexacyanoferrates – Comparison with Their Lanthanide Analogues

et al. 2011

Self Cite

View full text Add to dashboard Cite

show abstract

“…X-ray absorption spectroscopy, particularly Extended X-ray absorption fine structure (EXAFS), is a powerful experimental technique to characterize the solvation around metal ions. The technique provides short range structural information around them in solution with remarkable accuracy and sensitivity, among them actinoids [11][12][13]. In particular, EXAFS has a structural precision in the hundredth of an angstrom in determining coordination distances around an absorbing atom.…”

Section: Introductionmentioning

confidence: 99%

Combining EXAFS and Computer Simulations to Refine the Structural Description of Actinyls in Water

et al. 2020

View full text Add to dashboard Cite

EXAFS spectroscopy is one of the most used techniques to solve the structure of actinoid solutions. In this work a systematic analysis of the EXAFS spectra of four actinyl cations, [UO2]2+, [NpO2]2+, [NpO2]+ and [PuO2]2+ has been carried out by comparing experimental results with theoretical spectra. These were obtained by averaging individual contributions from snapshots taken from classical Molecular Dynamics simulations which employed a recently developed [AnO2]2+/+ –H2O force field based on the hydrated ion model using a quantum-mechanical (B3LYP) potential energy surface. Analysis of the complex EXAFS signal shows that both An-Oyl and An-OW single scattering paths as well as multiple scattering ones involving [AnO2]+/2+ molecular cation and first-shell water molecules are mixed up all together to produce a very complex signal. Simulated EXAFS from the B3LYP force field are in reasonable agreement for some of the cases studied, although the k= 6–8 Å−1 region is hard to be reproduced theoretically. Except uranyl, all studied actinyls are open-shell electron configurations, therefore it has been investigated how simulated EXAFS spectra are affected by minute changes of An-O bond distances produced by the inclusion of static and dynamic electron correlation in the quantum mechanical calculations. A [NpO2]+−H2O force field based on a NEVPT2 potential energy surface has been developed. The small structural changes incorporated by the electron correlation on the actinyl aqua ion geometry, typically smaller than 0.07 Å, leads to improve the simulated spectrum with respect to that obtained from the B3LYP force field. For the other open-shell actinyls, [NpO2]2+ and [PuO2]2+, a simplified strategy has been adopted to improve the simulated EXAFS spectrum. It is computed taking as reference structure the NEVPT2 optimized geometry and including the DW factors of their corresponding MD simulations employing the B3LYP force field. A better agreement between the experimental and the simulated EXAFS spectra is found, confirming the a priori guess that the inclusion of dynamic and static correlation refine the structural description of the open-shell actinyl aqua ions.

show abstract

“…Advances in theory coupled with sophisticated spectroscopic and structural analyses of actinide complexes and materials have transformed the way in which we view these elements from what was once considered mundane to utter fascination 1 2 3 4 . While tantalizing evidence that 5 f elements might utilize their valence orbitals in bonding was uncovered shortly after the Manhattan Project in the 1950s (ref.…”

mentioning

confidence: 99%

Emergence of californium as the second transitional element in the actinide series

et al. 2015

View full text Add to dashboard Cite

A break in periodicity occurs in the actinide series between plutonium and americium as the result of the localization of 5f electrons. The subsequent chemistry of later actinides is thought to closely parallel lanthanides in that bonding is expected to be ionic and complexation should not substantially alter the electronic structure of the metal ions. Here we demonstrate that ligation of californium(III) by a pyridine derivative results in significant deviations in the properties of the resultant complex with respect to that predicted for the free ion. We expand on this by characterizing the americium and curium analogues for comparison, and show that these pronounced effects result from a second transition in periodicity in the actinide series that occurs, in part, because of the stabilization of the divalent oxidation state. The metastability of californium(II) is responsible for many of the unusual properties of californium including the green photoluminescence.

show abstract

Solving the Hydration Structure of the Heaviest Actinide Aqua Ion Known: The Californium(III) Case

Cited by 27 publications

References 33 publications

Local Structure in Americium and Californium Hexacyanoferrates – Comparison with Their Lanthanide Analogues

Local Structure in Americium and Californium Hexacyanoferrates – Comparison with Their Lanthanide Analogues

Combining EXAFS and Computer Simulations to Refine the Structural Description of Actinyls in Water

Emergence of californium as the second transitional element in the actinide series

Contact Info

Product

Resources

About