Thermodynamic Properties of Actinides and Actinide Compounds

Konings, R.J.M.; Morss, Lester R.; Fuger, J.

doi:10.1007/978-94-007-0211-0_19

Cited by 25 publications

(33 citation statements)

References 211 publications

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“…3. The dashed lines are the recommended equations by Konings et al 1819,. however, these equations do not reproduce the heat capacity around the superionic transition19.…”

Section: Resultsmentioning

confidence: 99%

“…The results from Ralph21 were calculated using a quasi-local linear regression method on the enthalpy data. The choice of fitting method applied to enthalpy data to calculate specific heat values effects the outcome (values by Ralph21, Konings1819 and Fink20 are calculated using the method of applying a fit through enthaply data). Thus, to ensure a fair comparison, polynomials should be fitted to the MD results that are consistent with the experimental data, as done by Cooper et al 22…”

Section: Resultsmentioning

confidence: 99%

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Thermophysical properties and oxygen transport in (Thx,Pu1−x)O2

Galvin

Cooper

Rushton

et al. 2016

Sci Rep

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Using Molecular Dynamics, this paper investigates the thermophysical properties and oxygen transport of (Thx,Pu1−x)O2 (0 ≤ x ≤ 1) between 300–3500 K. In particular, the superionic transition is investigated and viewed via the thermal dependence of lattice parameter, linear thermal expansion coefficient, enthalpy and specific heat at constant pressure. Oxygen diffusivity and activation enthalpy are also investigated. Below the superionic temperature an increase of oxygen diffusivity for certain compositions of (Thx,Pu1−x)O2 compared to the pure end members is predicted. Oxygen defect formation enthalpies are also examined, as they underpin the superionic transition temperature and the increase in oxygen diffusivity. The increase in oxygen diffusivity for (Thx,Pu1−x)O2 is explained in terms of lower oxygen defect formation enthalpies for (Thx,Pu1−x)O2 than PuO2 and ThO2, while links are drawn between the superionic transition temperature and oxygen Frenkel disorder.

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“…3. The dashed lines are the recommended equations by Konings et al 1819,. however, these equations do not reproduce the heat capacity around the superionic transition19.…”

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Thermophysical properties and oxygen transport in (Thx,Pu1−x)O2

Galvin

Cooper

Rushton

et al. 2016

Sci Rep

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“…28,29 The literature available on kinetically inert organometallic complexes agree that U IV is more common and stable than U III , with the redox potentials of Np(Cp)4 and Np(Cp3)Cl around 0.7V below those for the U analogues, 30 and the stability of the An IV halides with respect to decomposition into An III and elemental halogen decreases in the order U > Np > Pu. 31 This means that commonly used organometallic ligands may be strongly influential in changing the preferred formal oxidation state of organo-neptunium complexes, allowing spontaneous reduction of a Np IV centre during a ligand exchange reaction. 32…”

Section: Redox Propertiesmentioning

confidence: 99%

Organometallic Neptunium Chemistry

2017

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Fifty years have passed since the foundation of organometallic neptunium chemistry, and yet only a handful of complexes have been reported, and even fewer have been fully characterized. Yet, increasingly, combined synthetic/spectroscopic/computational studies are demonstrating how covalently bonding, soft, carbocyclic organometallic ligands provide an excellent platform for advancing the fundamental understanding of the differences in orbital contributions and covalency in f-block metal-ligand bonding. Understanding the subtleties is the key to the safe handling and separations of the highly radioactive nuclei. This review describes the complexes that have been synthesized to date and presents a critical assessment of the successes and difficulties in their analysis and the bonding information they have provided. Because of increasing recent efforts to start new Np-capable air-sensitive inorganic chemistry laboratories, the importance of radioactivity, the basics of Np decay and its ramifications (including the radiochemical synthesis of one organometallic compound), and the available anhydrous starting materials are also surveyed. The review also highlights a range of instances in which important differences in the chemical behavior between Np and its closest neighbors, uranium and plutonium, are found.

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“…In the latter case, the shuttling of electrons between reducing agents and adsorbed UO 2 2+ is facilitated by the highly conductive surface of magnetite (Becker et al, 2001;Missana et al, 2003;Rosso and Becker, 2003;Renock and Becker, 2010;Gorski et al, 2012;Latta et al, 2012;Singer et al, 2012a;Singer et al, 2012b). The two-electron reduction of UO 2 2+ to U 4+ is more energetically favored than the one-electron reduction of UO 2 2+ to UO 2 + based on standard reduction potentials (i.e., E 0 U(VI)/U(IV) = 0.070 V, E 0 U(VI)/U(V) = −0.135 V, all potentials in this manuscript are with respect to the Ag/AgCl, saturated KCl,0.197 V vs. NHE) (Morris, 2002;Konings et al, 2006). However, direct reduction from UO 2 2+ to U 4+ is kinetically hindered due to the significant change between the structures of the reactant and the product, where the UO 2 2+ exists as the stable linear uranyl molecule with the short U=O bond (Burns, 1999).…”

Section: Introductionmentioning

confidence: 99%