Abstract
The simple system of tetraammonium octafluorouranate is employed to derive a fundamental understanding of the uranium-fluorine interaction. The structure is composed of isolated molecules, enabling a detailed examination of the U 4+ (f 2 ) ion. Characterization of single-crystals by X-ray diffraction, absorption spectroscopy, and magnetic analysis up to 45 T is combined with extensive theoretical treatment by CASSCF. The influence of different active spaces and representations of the structure is examined in the context of the experimental evidence. The Interacting Quantum Atoms method (IQA) is used to examine the nature of the U-F bond, concluding that there is a non-negligible degree of covalent character (9% of the total bond energy) in [UF 8 ] 4- . For the structural and theoretical reasons discussed herein, it is proposed that the structure of (NH 4 ) 4 UF 8 may be appropriately employed as a benchmark compound for future theoretical characterization of U(IV).
Original language | English |
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Pages (from-to) | 637-647 |
Number of pages | 11 |
Journal | Inorganic Chemistry |
Volume | 58 |
Issue number | 1 |
DOIs | |
State | Published - Jan 7 2019 |
Externally published | Yes |
Funding
This research was supported by the Center for Actinide Science and Technology (CAST), an Energy Frontier Research Center (EFRC) funded by the US Department of Energy (DOE), Office of Science, Basic Energy Sciences (BES), under Award Number DE-SC0016568. A portion of this work was performed at the National High Magnetic Field Laboratory, which is supported by the National Science Foundation Cooperative Agreement No. DMR-1157490 and No. DMR-1644779 and the State of Florida.