UF4 and the High-Pressure Polymorph HP-UF4 |
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| Authors: | Benjamin Scheibe Dr Jörn Bruns Prof?Dr Gunter Heymann Malte Sachs Prof?Dr Antti J Karttunen Clemens Pietzonka Dr Sergei I Ivlev Prof?Dr Hubert Huppertz Prof?Dr Florian Kraus |
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| Institution: | 1. Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Straße 4, 35032 Marburg, Germany;2. Institut für Anorganische Chemie, Universität zu Köln, Greinstr. 6, 50939 Köln, Germany;3. Institut für Allgemeine, Anorganische und Theoretische Chemie, Universität Innsbruck, Innrain 80–82, 6020 Innsbruck, Austria;4. Department of Chemistry and Materials Science, Aalto University, Kemistintie 1, 02150 Espoo, Finland |
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| Abstract: | A laboratory-scale synthesis of UF4 is presented that utilizes the reduction of UF6 with sulfur in anhydrous hydrogen fluoride. An excess of sulfur can be removed by vacuum sublimation, yielding pure UF4, as shown by powder X-ray diffraction, micro X-ray fluorescence analysis, infrared and Raman spectroscopy, as well as magnetic measurements. Furthermore, a single-crystalline, high-pressure modification of UF4 was obtained in a multi-anvil press at elevated temperatures. The high-pressure polymorph HP-UF4 was characterized by means of single-crystal and powder X-ray diffraction, as well as by magnetic measurements, and presents a novel crystal structure type. Quantum-chemical calculations show the HP-modification to be 10 kJ mol?1 per formula unit higher in energy compared to UF4. |
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| Keywords: | actinoids fluorine high-pressure chemistry magnetic properties uranium |
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