Probing the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msup><mml:mrow><mml:mi>Pu</mml:mi></mml:mrow><mml:mrow><mml:mn>4</mml:mn><mml:mo>+</mml:mo></mml:mrow></mml:msup></mml:math>magnetic moment in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi>PuF</mml:mi><mml:mn>4</mml:mn></mml:msub></mml:math>with<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mmultiscripts><mml:mi mathvariant="normal">F</mml:mi><mml:mprescripts /><mml:none /><mml:mn>19</mml:mn>

Capan, C.; Dempsey, Richard; Sinkov, Sergey I.; McNamara, Bruce K.; Cho, Herman

doi:10.1103/physrevb.93.224409

Cited by 10 publications

(9 citation statements)

References 34 publications

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“…For example, solid-state 17 O NMR measurements of UO 2 (CO 3 ), AnO 2 (An = Th, U, Np, Pu, Am), as well as mixed actinide oxide systems, U 1– x Np x O 2 , , have been reported. Solid-state 19 F NMR spectra of AnF 4 (An = Th, U, Pu) − and UO 2 F 2 have also been performed, as have solid-state 35 Cl and 37 Cl NMR measurements of [PuCl 6 ] 2– . Generally speaking, these measurements reveal that the anisotropic chemical shifts are highly sensitive to the local electronic ground state about the actinide center, providing a wealth of information about bonding and structure.…”

Section: Introductionmentioning

confidence: 99%

Probing the Electronic Structure of a Thorium Nitride Complex by Solid-State ¹⁵N NMR Spectroscopy

et al. 2020

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The solid-state 15 N NMR powder spectra of the thorium nitride complex, [K(18-crown-6)(THF) 2 ][(R 2 N) 3 Th(μ-15 N)Th(NR 2 ) 3 ] ([K][1-15 N], R = SiMe 3 ), and the thorium amide complex, [Th(NR 2 ) 3 ( 15 NH 2 )] (2-15 N), were recorded. The spectrum for [K][1-15 N] represents the first reported solid-state 15 N NMR data for an actinide complex. The experimentally measured tensor spans are Ω = 847 ppm for [K][1-15 N] and Ω = 237 ppm for 2-15 N. Both shielding tensors exhibit axial symmetry, which for [K][1-15 N] is consistent with a local rotational symmetry of its 15 N-labeled nitride ligand. For 2-15 N, the axial asymmetry can be rationalized by a quasi-free Th-NH 2 bond rotation in the solid-state. Density functional theory calculations overestimate the tensor span somewhat for [K][1-15 N], but provide isotropic shifts in good agreement with both the solid-state and solution values for both complexes. Natural localized molecular orbital analyses of the nuclear shielding reveal that the larger tensor span in [K][1-15 N] vs 2-15 N is primarily a consequence of more pronounced covalency of the σ(N−Th) bonds and large spin−orbit coupling due to significant Th 5f orbital contribution to those bonds, impacting the principal components of the shielding tensor perpendicular to the Th−N−Th axis. Overall, our analysis confirms the involvement of the 5f orbitals in Th−N multiple bonds and further demonstrates the value of solid-state NMR spectroscopy for interrogating actinide-ligand bonding.

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Section: Introductionmentioning

confidence: 99%

Probing the Electronic Structure of a Thorium Nitride Complex by Solid-State ¹⁵N NMR Spectroscopy

et al. 2020

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“…The generally accepted chemical bonding picture is that for early actinides the bonding varies from ionic to polarised-covalent as a function of An-oxidation state and ligands, with this range sitting intermediate to the ionic lanthanides and usually much more covalent d transition metal complexes 5,7,8,10,11 . Probing actinide covalency is challenging, but in recent years progress has been made using experimental approaches, underpinned by quantum chemical calculations, including K-edge X-ray absorption near edge spectroscopy [12][13][14][15][16][17][18] , pulsed electron paramagnetic resonance spectroscopy 19 , and nuclear magnetic resonance (NMR) spectroscopy [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36] . These investigations have begun to place the bonding descriptions of An-L bonding on a rigorous, quantitative footing, and have been consistent with the status quo bonding description of early actinides.…”

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Exceptional uranium(VI)-nitride triple bond covalency from 15N nuclear magnetic resonance spectroscopy and quantum chemical analysis

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Berryman

et al. 2021

Nat Commun

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Determining the nature and extent of covalency of early actinide chemical bonding is a fundamentally important challenge. Recently, X-ray absorption, electron paramagnetic, and nuclear magnetic resonance spectroscopic studies have probed actinide-ligand covalency, largely confirming the paradigm of early actinide bonding varying from ionic to polarised-covalent, with this range sitting on the continuum between ionic lanthanide and more covalent d transition metal analogues. Here, we report measurement of the covalency of a terminal uranium(VI)-nitride by 15N nuclear magnetic resonance spectroscopy, and find an exceptional nitride chemical shift and chemical shift anisotropy. This redefines the 15N nuclear magnetic resonance spectroscopy parameter space, and experimentally confirms a prior computational prediction that the uranium(VI)-nitride triple bond is not only highly covalent, but, more so than d transition metal analogues. These results enable construction of general, predictive metal-ligand 15N chemical shift-bond order correlations, and reframe our understanding of actinide chemical bonding to guide future studies.

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“…These values (−520 and −791 ppm) are higher than the strongest ones determined in diamagnetic fluorides (between −370 and −410 ppm for CeF4 57 and up to −410 ppm for NbF5 56 ) but remain nevertheless significantly smaller than those determined recently in PuF4 (∼3700 ppm). 58 The 19 F MAS (64 kHz) NMR spectra of CeF3 and Ce1−xSrxF3−x (x = 0.01, 0.025, 0.05, 0.07 and 0.10) samples are reported in Fig. 9.…”

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The key role of the composition and structural features in fluoride ion conductivity in tysonite Ce_1−xSr_xF_3−x solid solutions

et al. 2017

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Pure tysonite-type CeSrF solid solutions for 0 ≤ x < 0.15 were prepared by a solid-state route at 900 °C. The cell parameters follow Vegard's laws for 0 ≤ x ≤ 0.10 and the solubility limit is identified (0.10 < x < 0.15). For 0 ≤ x ≤ 0.05, the F2-(Ce,Sr) and F3-(Ce,Sr) bond distances into [CeSrF] slabs strongly vary with x. This slab buckling is maximum around x = 0.025 and strongly affects the more mobile F1 fluoride ions located between the slabs. The F MAS NMR spectra show the occurrence of F1-F2,3 exchange at 64 °C. The fraction of mobile F2,3 atoms deduced from the relative intensity of the NMR resonance is maximum for CeSrF (22% at 64 °C) while this fraction linearly increases with x for LaAEF (AE = Ba, Sr). The highest conductivity found for CeSrF (3 × 10 S cm at RT, E = 0.31 eV) is correlated to the largest dispersion of F2-(Ce,Sr) and F3-(Ce,Sr) distances which induces the maximum sheet buckling. Such a relationship between composition, structural features and fluoride ion conductivity is extended to other tysonite-type fluorides. The key role of the difference between AE and RE ionic radii and of the thickness of the slab buckling is established and could allow designing new ionic conductors.

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Probing thePu4+magnetic moment inPuF4withF19

Cited by 10 publications

References 34 publications

Probing the Electronic Structure of a Thorium Nitride Complex by Solid-State ¹⁵N NMR Spectroscopy

Probing the Electronic Structure of a Thorium Nitride Complex by Solid-State ¹⁵N NMR Spectroscopy

Exceptional uranium(VI)-nitride triple bond covalency from 15N nuclear magnetic resonance spectroscopy and quantum chemical analysis

The key role of the composition and structural features in fluoride ion conductivity in tysonite Ce_1−xSr_xF_3−x solid solutions

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Probing thePu4+magnetic moment inPuF4withF19

Cited by 10 publications

References 34 publications

Probing the Electronic Structure of a Thorium Nitride Complex by Solid-State 15N NMR Spectroscopy

Probing the Electronic Structure of a Thorium Nitride Complex by Solid-State 15N NMR Spectroscopy

Exceptional uranium(VI)-nitride triple bond covalency from 15N nuclear magnetic resonance spectroscopy and quantum chemical analysis

The key role of the composition and structural features in fluoride ion conductivity in tysonite Ce1−xSrxF3−x solid solutions

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Product

Resources

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Probing the Electronic Structure of a Thorium Nitride Complex by Solid-State ¹⁵N NMR Spectroscopy

Probing the Electronic Structure of a Thorium Nitride Complex by Solid-State ¹⁵N NMR Spectroscopy

The key role of the composition and structural features in fluoride ion conductivity in tysonite Ce_1−xSr_xF_3−x solid solutions