Identification of hexanuclear Actinide(IV) carboxylates with Thorium, Uranium and Neptunium by EXAFS spectroscopy - Université de Bourgogne Accéder directement au contenu
Communication Dans Un Congrès Année : 2013

Identification of hexanuclear Actinide(IV) carboxylates with Thorium, Uranium and Neptunium by EXAFS spectroscopy

Résumé

Hydrated actinide(IV) ions undergo hydrolysis and further polymerization and precipitation with increasing pH. The resulting amorphous and partly crystalline oxydydroxides AnO(n)(OH)(4-2n)center dot xH(2)O can usually be observed as colloids above the An(IV) solubility limit. The aging process of such colloids results in crystalline AnO(2). The presence of carboxylates in the solution prevents the occurrence of such colloids by formation of polynuclear complexes through a competing reaction between hydrolysis and ligation. The majority of recently described carboxylates reveals a hexanuclear core of [An(6)(mu(3)-O)(4)(mu(3)-OH)(4)](12+) terminated by 12 carboxylate ligands. We found that the An(IV) carboxylate solution species remain often preserved in crystalline state. The An(IV) carboxylates show An-An distances which are similar to 0.03 angstrom shorter than the An-An distances in AnO(2) like colloids. The difference in the distances could be used to identify such species in solution
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Dates et versions

hal-01572812 , version 1 (08-08-2017)

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Christoph Hennig, Shinobu Takao, Koichiro Takao, Stephan Weiss, Werner Kraus, et al.. Identification of hexanuclear Actinide(IV) carboxylates with Thorium, Uranium and Neptunium by EXAFS spectroscopy. 15th International Conference on X-Ray Absorption Fine Structure (XAFS), Jul 2012, Beijing, China. 5 p., ⟨10.1088/1742-6596/430/1/012116⟩. ⟨hal-01572812⟩
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