| Title: |
Stabilities of the Aqueous Complexes Cm(CO$_3)_3^3$- and Am(CO$_3)_3^3$- in the Temperature Range 10-70 \degres C |
| Authors: |
Vercouter, T.; Vitorge, P.; Amekraz, B.; Giffaut, E.; Hubert, S.; Moulin, C. |
| Contributors: |
Laboratoire Analyse et environnement (LAE); Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université d'Évry-Val-d'Essonne (UEVE)-Centre National de la Recherche Scientifique (CNRS); Laboratoire de Spéciation des Radionucléides et des Molécules (LSRM); Département de Physico-Chimie (DPC); CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)); Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)); Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay; Institut de Physique Nucléaire d'Orsay (IPNO); Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS); Agence Nationale pour la Gestion des Déchets Radioactifs (ANDRA) |
| Source: |
ISSN: 0020-1669. |
| Publisher Information: |
CCSD; American Chemical Society |
| Publication Year: |
2005 |
| Subject Terms: |
[PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph] |
| Description: |
RADIOCH ; International audience ; The carbonate complexation of curium(III) in aqueous solutions with high ionic strength was investigated below solubility limits in the 10−70 °C temperature range using time-resolved laser-induced fluorescence spectroscopy (TRLFS). The equilibrium constant, K 3 , for the Cm(CO 3 ) 2 - + CO 3 2 - ⇌ Cm(CO 3 ) 3 3 - reaction was determined (log K 3 = 2.01 ± 0.05 at 25°C, I = 3 M (NaClO 4 )) and compared to scattered previously published values. The log K 3 value for Cm(III) was found to increase linearly with 1/ T , reflecting a negligible temperature influence on the corresponding molar enthalpy change, Δ r H 3 = 12.2 ± 4.4 kJ mol - 1 , and molar entropy change, Δ r S 3 = 79 ± 16 J mol - 1 K - 1 . These values were extrapolated to I = 0 with the SIT formula (Δ r H 3 ° = 9.4 ± 4.8 kJ mol - 1 , Δ r S 3 ° = 48 ± 23 J mol - 1 K - 1 , log K 3 ° = 0.88 ± 0.05 at 25°C). Virtually the same values were obtained from the solubility data for the analogous Am(III) complexes, which were reinterpreted considering the transformation of the solubility-controlling solid. The reaction studied was found to be driven by the entropy. This was interpreted as a result of hydration changes. As expected, excess energy changes of the reaction showed that the ionic strength had a greater influence on Δ r S 3 than it did on Δ r H 3 . |
| Document Type: |
article in journal/newspaper |
| Language: |
English |
| DOI: |
10.1021/ic050214n |
| Availability: |
https://in2p3.hal.science/in2p3-00024570; https://in2p3.hal.science/in2p3-00024570v1/document; https://in2p3.hal.science/in2p3-00024570v1/file/hubert.pdf; https://doi.org/10.1021/ic050214n |
| Rights: |
info:eu-repo/semantics/OpenAccess |
| Accession Number: |
edsbas.4F4FAAF2 |
| Database: |
BASE |