The magnetic behavior of Sf6 ions Am3+ and Cm4+

Soderholm, L.

doi:10.1016/0022-5088(87)90462-0

Cited by 19 publications

(8 citation statements)

References 15 publications

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“…[36][37][38] However, experimental results show a temperature-independent paramagnetism (TIP), and surprisingly strong magnetic moments for various Am(III) compounds have been reported. 39,40 Initial assessment of NMR spectra indicates diamagnetic behaviour, as the measured linewidths are below 2 Hz, and all 1 H and 13 C chemical shifts are accessible in 1D spectra. All resonances are well-resolved and chemical shifts are similar to those of an isostructural Lu(III)…”

Section: Resultsmentioning

confidence: 99%

Evidence for covalence in a N-donor complex of americium(iii)

et al. 2013

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The molecular origin of the selectivity of N-donor ligands, such as alkylated bis-triazinyl pyridines (BTPs), for actinide complexation in the presence of lanthanides is still largely unclear. NMR investigations of an Am(nPrBTP)3(3+) complex with a (15)N labelled ligand showed that it exhibits large differences in (15)N chemical shift for coordinating N-atoms in comparison to both lanthanide(III) complexes and the free ligand. The temperature dependence of NMR chemical shifts observed for this complex indicates a weak paramagnetism. This fact and the observed large chemical shift for bound nitrogen atoms allow us to conclude that metal-ligand bonding in the reported Am(III) N-donor complex has a larger share of covalence than in lanthanide complexes. This may account for the observed selectivity.

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Section: Resultsmentioning

confidence: 99%

Evidence for covalence in a N-donor complex of americium(iii)

et al. 2013

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“…50 On the other hand, surprisingly large magnetic susceptibilities and magnetic moments have been reported for different Am(III) compounds in the solid state, indicating that Am(III) is not purely diamagnetic. [51][52][53][54] Recently, the magnetic susceptibility of Am(III) in perchloric acid solution was studied using the Evans NMR method. 55 Results show a signicant deviation from the expected magnetic behavior for Am(III) and Cf(III).…”

Section: Theoretical and Nmr Backgroundmentioning

confidence: 99%

NMR and TRLFS studies of Ln(iii) and An(iii) C5-BPP complexes

et al. 2015

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“…[60] It has been shown that, for a range of off-stoichiometric compounds CmO 2−x , both the lattice parameter and magnetic moment increase with x. [61,62,63] Given the expected moments of Cm 3+ (5f 7 ; µ ef f =7.94 µ B ) and Cm 4+ (5f 6 ; µ ef f =0 µ B ) it was noted that this trend indicates an increase in the number of Cm 3+ impurities as we move away from stoichiometry.…”

Section: Sic-lsd Electronic Structurementioning

confidence: 99%

“…Attempts to explain this discrepancy, range from a possible existence of an impurity phase, not registered in the experiments, to assuming a covalent, rather than an ionic, picture for the ground state. [60] It has also been conjectured that a more complex ground state which includes some admixture of the excited J = 1 state of Cm 4+ might be required. [64] The lattice parameter measurements yield two different values for CmO 2 , depending on whether the shortlived curium isotope of mass number 244 is used (a = 5.372Å), [65] or the long-lived curium isotope of mass number 248 is used (a = 5.359Å).…”

Section: Sic-lsd Electronic Structurementioning

confidence: 99%

Electronic structure and ionicity of actinide oxides from first principles

et al. 2010

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The ground state electronic structures of the actinide oxides AO, A2O3 and AO2 (A=U, Np, Pu, Am, Cm, Bk, Cf) are determined from first-principles calculations, using the self-interaction corrected local spin-density (SIC-LSD) approximation. Emphasis is put on the degree of f-electron localization, which for AO2 and A2O3 is found to follow the stoichiometry, namely corresponding to A 4+ ions in the dioxide and A 3+ ions in the sesquioxides. In contrast, the A 2+ ionic configuration is not favorable in the monoxides, which therefore become metallic. The energetics of the oxidation and reduction of the actinide dioxides is discussed, and it is found that the dioxide is the most stable oxide for the actinides from Np onwards. Our study reveals a strong link between preferred oxidation number and degree of localization which is confirmed by comparing to the ground state configurations of the corresponding lanthanide oxides. The ionic nature of the actinide oxides emerges from the fact that only those compounds will form where the calculated ground state valency agrees with the nominal valency expected from a simple charge counting.

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The magnetic behavior of Sf6 ions Am3+ and Cm4+

Cited by 19 publications

References 15 publications

Evidence for covalence in a N-donor complex of americium(iii)

Evidence for covalence in a N-donor complex of americium(iii)

NMR and TRLFS studies of Ln(iii) and An(iii) C5-BPP complexes

Electronic structure and ionicity of actinide oxides from first principles

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