Optical and X-ray data on a group of isostructural uranium and plutonium compounds

Staritzky, Eugene.; Singer, J.

doi:10.1107/s0365110x52001489

Cited by 73 publications

(39 citation statements)

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“…48,53 While the first reports of this salt indicated that the most stable phase was a tetragonal phase, the tetragonal phase was not ever able to be produced in this laboratory. 53 The preparation of a tetragonal phase is mentioned only among the earliest description of this salt and has never been subsequently reported.…”

Section: ■ Results and Discussionmentioning

confidence: 96%

Structure, Phase Transitions, and Isotope Effects in [(CH₃)₄N]₂PuCl₆

Wilson

2015

Inorg. Chem.

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The single-crystal X-ray diffraction structure of [(CH3)4N]2PuCl6 is presented for the first time, resolving long-standing confusion and speculation regarding the structure of this compound in the literature. A temperature-dependent study of this compound shows that the structure of [(CH3)4N]2PuCl6 undergoes no fewer than two phase transitions between 100 and 360 K. The phase of [(CH3)4N]2PuCl6 at room temperature is Fd3̅c a = 26.012(3) Å. At 360 K, the structure is in space group Fm3̅m, with a = 13.088(1) Å. The plutonium octahedra and tetramethylammonium cations undergo a rotative displacement, and the degree of rotation varies with temperature, giving rise to the phase transition from Fm3̅m to Fd3̅c as the crystal is cooled. Synthesis and structural studies of the deuterated salt [(CD3)4N]2PuCl6 suggest that there is an isotopic effect associated with this phase transition, as revealed by a changing transition temperature in the deuterated versus protonated compound, indicating that the donor-acceptor interactions between the tetramethylammonium cations and the hexachloroplutonate anions are driving the phase transformation.

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Section: ■ Results and Discussionmentioning

confidence: 96%

Structure, Phase Transitions, and Isotope Effects in [(CH₃)₄N]₂PuCl₆

Wilson

2015

Inorg. Chem.

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“…7 Even though there have been many experimental and computational studies of [U(f 1 )Cl 6 ] − in condensed phases, 1,8-16 the accurate account of the electronic structure of the [U(f 2 )Cl 6 ] 2− species has been challenging owing to the highly complex f 2 system and the perturbations caused by interactions with the countercations in crystal and solution phases. [17][18][19][20][21] Anion photoelectron spectroscopy (PES) is a powerful experimental technique to probe the ground and excited states of neutral species, through electron detachment from singly charged anions. We have developed PES techniques to study solution-phase species, both singly charged and multiply charged anions, in the gas phase using electrospray ionization a) J. Su and P. D. Dau contributed equally to this work.…”

Section: Introductionmentioning

confidence: 99%

Photoelectron spectroscopy and theoretical studies of gaseous uranium hexachlorides in different oxidation states: UCl6q− (q = 0–2)

Dau

Liu

et al. 2015

The Journal of Chemical Physics

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Uranium chlorides are important in actinide chemistry and nuclear industries, but their chemical bonding and many physical and chemical properties are not well understood yet. Here, we report the first experimental observation of two gaseous uranium hexachloride anions, UCl6 (-) and UCl6 (2-), which are probed by photoelectron spectroscopy in conjunction with quantum chemistry calculations. The electron affinity of UCl6 is measured for the first time as +5.3 eV; its second electron affinity is measured to be +0.60 eV from the photoelectron spectra of UCl6 (2-). We observe that the detachment cross sections of the 5f electrons are extremely weak in the visible and UV energy ranges. It is found that the one-electron one-determinental molecular orbital picture and Koopmans' theorem break down for the strongly internally correlated U-5f(2) valence shell of tetravalent U(+4) in UCl6 (2-). The calculated adiabatic and vertical electron detachment energies from ab initio calculations agree well with the experimental observations. Electronic structure and chemical bonding in the uranium hexachloride species UCl6 (2-) to UCl6 are discussed as a function of the oxidation state of U.

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“…C Ftil3itz, with the SiF,, octahedra in a"ferro7' arrangement (34). Thc F I I I~I I I symmetry also appears to occur in a number of (Mc,N)?MX(, chlorides and brornides where M is a 5/' elcment (Th, Pa, U. Pu) and in thc high-temperature form of (Et4N)2PuC16 (35)(36)(37), while tlie corresponding (Et,N),MCI, and (Et,N)?PaBr(, at room temperature crystallize in Ftirt,rtn C Ftn3tr1 (36,37). (Et,N)?PaF(, is dimorphic, fcc and tetragonal, the latter form (isostructural with the U compound) probably related to Fti131n; (Et,N)ZPaOCIS is stated to be monoclinic.…”

Section: Dirner~sioils Of Tlre Siici Octahedramentioning

confidence: 99%

Alkylammonium hexachlorostannates(IV), (R_nNH_4−n)₂SnCl₆: crystal structure, infrared spectrum, and hydrogen bonding

Knop¹,

Cameron²,

James³

et al. 1983

Can. J. Chem.

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In an effort to advance our understanding of the principles governing the structures of and the hydrogen bonding in alkylammonium hexachlorostannates(IV), (RnNH4−n)2SnCl6, we have determined the room-temperature crystal structures of (Me2NH2)2SnCl6 and (Me3NH)2SnCl6 (variants of the antifluorite structure); (EtNH3)2SnCl6 and (n-PrNH3)2SnCl6 (anti-Cdl2 type, with orientational disorder in the Et compound); and (n-Pr3NH)2SnCl6. We have also studied the infrared spectra in the regions of the NH and ND stretching fundamentals, between 10 and 293 K, of these five compounds and of (MeNH3)2SnCl6, (Me3NH)2SnBr6, (Et2NH2)2SnCl6, (n-Bu3NH)2SnCl6 and, in less detail, the mixed-anion salt (n-Pr2NH2)3(SnCl6)Cl. The spectra are often complicated by Ferim resonance involving absorptions diagnostically critical for the strength and type of [Formula: see text] bonding and for the site symmetry at the N atom. In this respect they are less useful than the corresponding spectra of the unsubstituted ammonium compounds reported previously. Several of the spectra provide striking examples of temperature-tuned Fermi resonance of NH and ND vibrations. The [Formula: see text] bonds are invariably trifurcated, bifurcated, or at least highly bent; these characteristics give rise to anomalous temperature dependence of the frequencies of the NH and ND stretching fundamentals. Temperature-induced transitions were detected in (Me2NH2)2SnCl6 (Ttr ~ 100 K), Et NH3)2SnCl6 (Ttr ~ 125 K), and (Et2NH2)2SnCl6 (Ttr ~ 330 K). The specific results for the ten compounds studied arc discussed in detail. The discussion also includes the limits of usefulness of the isotopisc dilution technique; symmetry aspects of the cation–anion packing in alkylammonium hexahalometallates(IV); symmetries of the arrangements of the SnCl6 octahedra; the geometry of hydrogen bonding in (RnNH4−n)2SnCl6; and the possibility of detection of the presence of hydrogen bonding from molecular volume trends.

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Optical and X-ray data on a group of isostructural uranium and plutonium compounds

Cited by 73 publications

References 1 publication

Structure, Phase Transitions, and Isotope Effects in [(CH₃)₄N]₂PuCl₆

Structure, Phase Transitions, and Isotope Effects in [(CH₃)₄N]₂PuCl₆

Photoelectron spectroscopy and theoretical studies of gaseous uranium hexachlorides in different oxidation states: UCl6q− (q = 0–2)

Alkylammonium hexachlorostannates(IV), (R_nNH_4−n)₂SnCl₆: crystal structure, infrared spectrum, and hydrogen bonding

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Optical and X-ray data on a group of isostructural uranium and plutonium compounds

Cited by 73 publications

References 1 publication

Structure, Phase Transitions, and Isotope Effects in [(CH3)4N]2PuCl6

Structure, Phase Transitions, and Isotope Effects in [(CH3)4N]2PuCl6

Photoelectron spectroscopy and theoretical studies of gaseous uranium hexachlorides in different oxidation states: UCl6q− (q = 0–2)

Alkylammonium hexachlorostannates(IV), (RnNH4−n)2SnCl6: crystal structure, infrared spectrum, and hydrogen bonding

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Product

Resources

About

Structure, Phase Transitions, and Isotope Effects in [(CH₃)₄N]₂PuCl₆

Structure, Phase Transitions, and Isotope Effects in [(CH₃)₄N]₂PuCl₆

Alkylammonium hexachlorostannates(IV), (R_nNH_4−n)₂SnCl₆: crystal structure, infrared spectrum, and hydrogen bonding