Systematics in the Magnetic Properties of Ternary Actinoid Oxides

Bickel, M.; Kanellakopulos, Β.

doi:10.1006/jssc.1993.1348

Cited by 20 publications

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“…The obtained moment is much smaller than that expected for a free f ion (2.54 ), which indicates that the crystal field with octahedral symmetry has a significant effect on the magnetic properties of the Pr> ion. A comparably small magnetic moment has been found in the Pr> ion for BaPrO and in the actinide ion with [Rn]5f configuration ([Rn]: Rn core) in the same octahedral crystal field environment (13)(14)(15).…”

Section: Resultsmentioning

confidence: 88%

Magnetic Susceptibilities and Electron Paramagnetic Resonance Spectra of Lithium-Rich Lanthanide Oxides Li8Pro6and Li8TbO6

Hinatsu¹

1997

Journal of Solid State Chemistry

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Section: Resultsmentioning

confidence: 88%

Magnetic Susceptibilities and Electron Paramagnetic Resonance Spectra of Lithium-Rich Lanthanide Oxides Li8Pro6and Li8TbO6

Hinatsu¹

1997

Journal of Solid State Chemistry

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“…The electronic configuration of [Rn]5f 1 in UBr 5 results in a 2 F 5/2 atomic ground state with an effective atomic moment of 2.54 μ B. Crystal‐field effects and covalent interactions reduce this value in actinoid compounds, as is the case for UBr 5 . Bickel and co‐workers reported a linear correlation of the magnitude of χ 0 and μ eff for various 5f 1 actinoid oxides . They explain this effect in terms of a different amount of mixing of higher J multiplets from the ligand atoms into the ground state.…”

Section: Resultsmentioning

confidence: 99%

“…[53] Bickel and co-workersr eported al inear correlation of the magnitude of c 0 and m eff for various 5f 1 actinoid oxides. [54] They explain this effect in terms of ad ifferent amount of mixing of higher J multiplets from the ligand atoms into the ground state. As shown in FigureS8, our results agree well with their findings.…”

Section: Lt-uclmentioning

confidence: 99%

A Revised Structure Model for the UCl₆ Structure Type, Novel Modifications of UCl₆ and UBr₅, and a Comment on the Modifications of Protactinium Pentabromides

Deubner

Rudel

Sachs

et al. 2019

Chemistry A European J

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The redetermination of the crystal structure of trigonal UCl6, which is the eponym for the UCl6 structure type, showed that certain atomic coordinates had been incorrectly reported. This led to noticeably different U−Cl distances within the octahedral UCl6 molecule (2.41 and 2.51 Å). Within the revised structure model presented here, which is based on single crystal data as well as quantum chemical calculations, all U−Cl distances are essentially equal within standard uncertainty (2.431(5), 2.437(5), and 2.439(6) Å). This room temperature modification, called rt‐UCl6, crystallizes in the trigonal space group Ptrue3‾ m1, No. 164, hP21, with a=10.907(2), c=5.9883(12) Å, V=616.9(2) Å3, Z=3 at T=253 K. A new low‐temperature (lt) modification of UCl6 is also presented that was obtained by cooling a single crystal of rt‐UCl6. The phase change occurs between 150 and 175 K. lt‐UCl6 crystallizes isotypic to a low‐temperature modification of SF6 in the monoclinic crystal system, space group C2/m, No. 12, mS42, with a=17.847(4), b=10.8347(18), c=6.2670(17) Å, β=96.68(2)°, V=1203.6(5) Å3, Z=6 at 100 K. The Cl anions form a close‐packed structure corresponding to the α‐Sm type with uranium atoms in the octahedral voids. During the synthesis of UBr5 a new modification was obtained that crystallizes in the triclinic crystal system, space group Ptrue1‾ , No. 2, aP36, with a=10.4021(6), b=11.1620(6), c=12.2942(7) Å, α=68.3340(10)°, β=69.6410(10)° and γ=89.5290(10)°, V=1231.84(12) Å3, Z=3 at T=100 K. In this structure the UBr5 units are dimerized to U2Br10 molecules. The Br anions also form a close‐packed structure of the α‐Sm type with adjacent uranium atoms in the octahedral voids. Comparisons of the crystal structures of the compounds MX5 (M=Pa, U; X=Cl, Br) show that the crystal structure of monoclinic α‐PaBr5 is probably not correct.

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“…The 2 F 5/2 ground state manifold shows a degeneracy of (2J + 1) = 6, while the 2 F 7/2 excited state has a degeneracy of 8. However, as the energy associated with the 2 F 5/2 to 2 F 7/2 transition (4000-8000 cm −1 ) is usually much larger than k B T at room temperature (203 cm −1 , with k B Boltzmann constant) for such 5f 1 systems, only the ground state is populated at room temperature [39]. The electronic entropy contribution S o el (Np 6+ ) expressed in Eq.…”

Section: Tablementioning

confidence: 99%

Low temperature heat capacity of α-Na2NpO4

et al. 2015

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a b s t r a c tThe heat capacity of˛-Na 2 NpO 4 has been measured for the first time in the temperature range 2.1-301 K using a Quantum Design PPMS (Physical Property Measurement System) calorimeter. The heat capacity and entropy values at 298.15 K have been derived as C o p,m (˛-Na 2 NpO 4 , cr, 298.15 K) = (151.9 ± 4.6) J K −1 mol −1 and S o m (˛-Na 2 NpO 4 , cr, 298.15 K) = (178.3 ± 4.3) J K −1 mol −1 , respectively. The standard entropy of˛-Na 2 NpO 4 follows the trend shown by the isostructural compound -Na 2 UO 4 and the alkaline earth uranates MgUO 4 , SrUO 4 , BaUO 4 , and Cs 2 UO 4 . When combined with the entropies of the constituent elements, these data yield a standard entropy of formation at 298.15 K as f S o m (˛-Na 2 NpO 4 , cr, 298.15 K) = − (385.1 ± 4.3) J K −1 mol −1 . Using the enthalpy of formation tabulated in the literature, the standard Gibbs energy of formation was calculated at 298.15 K as f G o m (˛-Na 2 NpO 4 , cr, 298.15 K) =(−1649.0 ± 5.8) kJ mol −1 .

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Systematics in the Magnetic Properties of Ternary Actinoid Oxides

Cited by 20 publications

References 0 publications

Magnetic Susceptibilities and Electron Paramagnetic Resonance Spectra of Lithium-Rich Lanthanide Oxides Li8Pro6and Li8TbO6

Magnetic Susceptibilities and Electron Paramagnetic Resonance Spectra of Lithium-Rich Lanthanide Oxides Li8Pro6and Li8TbO6

A Revised Structure Model for the UCl₆ Structure Type, Novel Modifications of UCl₆ and UBr₅, and a Comment on the Modifications of Protactinium Pentabromides

Low temperature heat capacity of α-Na2NpO4

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Systematics in the Magnetic Properties of Ternary Actinoid Oxides

Cited by 20 publications

References 0 publications

Magnetic Susceptibilities and Electron Paramagnetic Resonance Spectra of Lithium-Rich Lanthanide Oxides Li8Pro6and Li8TbO6

Magnetic Susceptibilities and Electron Paramagnetic Resonance Spectra of Lithium-Rich Lanthanide Oxides Li8Pro6and Li8TbO6

A Revised Structure Model for the UCl6 Structure Type, Novel Modifications of UCl6 and UBr5, and a Comment on the Modifications of Protactinium Pentabromides

Low temperature heat capacity of α-Na2NpO4

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A Revised Structure Model for the UCl₆ Structure Type, Novel Modifications of UCl₆ and UBr₅, and a Comment on the Modifications of Protactinium Pentabromides