Gas-Phase Reactions of Bare and Ligated Uranium Ions with Sulfer Hexafluoride

Journal Article · Thu Jan 01 04:00:00 EST 2004 · Journal of Physical Chemistry A

DOI:https://doi.org/10.1021/jp037175q· OSTI ID:1003177

Jackson, Glen P. ^[1]; Gibson, John K ^[2]

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1. Ohio University, Athens
2. ORNL

Reactions of bare and ligated uranium ions with sulfur hexafluoride were studied in a quadrupole ion trap mass spectrometer. Bare U{sup +} was found to react rather efficiently with SF{sub 6} (k/k{sub ADO} {approx} 0.4) to produce both UF{sub n}{sup +} (n = 1, 2, 3, 4) and SF{sub n}{sup +} (n = 1, 2, 3). Whereas the UF{sup +}/SF{sub 6} reaction rate was essentially the same as that for U{sup +}/SF{sub 6}, both UF{sub 2}{sup +} and UF{sub 3}{sup +} were inert; this is attributed to a repulsive interaction between UF{sub n}{sup +} and SF{sub 6} when n exceeds 1. Reactions of UF{sup +} (k/k{sub ADO} {approx} 0.2) and UF{sub 2}{sup +} (k/k{sub ADO} {approx} 0.05) with H{sub 2}O resulted in both F {yields} OH exchange and oxidation. In contrast, UF{sub 3}{sup +} reacted very efficiently with H{sub 2}O (k/k{sub ADO} {approx} 1), exhibiting only F {yields} OH exchange. The primary ion products of the UO{sup +}/SF{sub 6} reaction (k/k{sub ADO} {approx} 0.2) were SF{sub 3}{sup +} and UOF{sub 2}{sup +}; those of the UOH{sup +}/SF{sub 6} reaction (k/k{sub ADO} {approx} 0.3) were SF{sub 3}{sup +} and UOF{sup +}. The reaction results are discussed in the context of a previously proposed reaction model, the distinctive chemistry of uranium, and thermodynamic considerations. The results illuminate the nature of uranium as well as general aspects of the interaction of bare and ligated transition-metal ions with SF{sub 6}. Results for collision-induced dissociation (CID) of selected uranium molecular ions support the concept of CID being a quasithermal process under these experimental conditions, with rearrangements prior to fragmentation possible for certain ions.

• Research Organization: Oak Ridge National Laboratory (ORNL)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1003177
• Journal Information: Journal of Physical Chemistry A, Journal Name: Journal of Physical Chemistry A Journal Issue: 6 Vol. 108; ISSN 1089-5639; ISSN 1520-5215
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
CHEMISTRY
DISSOCIATION
FRAGMENTATION
INTERACTIONS
IONS
MASS SPECTROMETERS
MOLECULAR IONS
OXIDATION
QUADRUPOLES
REACTION KINETICS
SULFUR
THERMODYNAMICS
URANIUM
URANIUM IONS
YIELDS