Go to the EndNote Online site through the Harvard proxy server.EndNote Basic does not let you transfer attached PDF files. Harvard users have access to EndNote Basic and need not purchase EndNote to use it (EndNote Basic does not involve the desktop version). Is not as robust an online system as some other tools.Is not as robust a tool as the desktop version.Is recommended for those who particularly like the interface and want the advantages of a Web-based library.Synchronizes your library across devices including iPad (using EndNote app).Creates bibliographies in Word documents (using a limited number of citation styles).Manages references in an online library.Considering the importance of UF 4 in the production of nuclear fuel and weapons, the results presented herein are widely applicable to numerous nuclear science fields where uranium detection and speciation in humid environments is of value, including nuclear nonproliferation and nuclear forensics.EndNote Basic is the online-only version of EndNote. Therefore, we postulate that NMR spectroscopy and X-ray diffraction, which are well-suited for bulk analysis, are less suited than Raman spectroscopy to observe the surface-based reactions that occur to UF 4 when exposed to humid air.
Microscopy measurements suggest that the observed reactions between UF 4 and water occur primarily on the surface of UF 4 particulates via a method that is visually similar to surface corrosion of metals. Despite the rich chemical speciation observed in our Raman spectroscopy measurements, X-ray diffraction and 19F NMR measurements on the same material showed no changes.
In contrast, UF 4 exposed to 50% relative humidity slightly decomposes into UO 2F 2, Schoepite-like uranium complexes, and possibly a high order uranium oxide that eluded chemical assignment (U xO y).
It was found that anhydrous UF 4 slightly oxidizes over the course of thirteen days to Schoepite-like uranium complexes and possibly UO 3. Of these, only Raman spectroscopy proved to be particularly useful at observing chemical changes to UF 4. In our report, we employ a battery of physiochemical probing techniques to explore potential hydrolysis, including Raman spectroscopy, powder X-ray diffraction, 19F nuclear magnetic resonance spectroscopy, scanning electron microscopy, and focused ion beam microscopy with energy-dispersive X-ray spectroscopy. This hydrolysis was previously reported to proceed slowly or not at all (depending on the percent relative humidity) however, previous reports relied primarily on X-ray diffraction methods to probe uranium speciation. This manuscript describes the chemical transformations that occur during hydrolysis of uranium tetrafluoride (UF 4) due to its storage in humid air (85% and 50% relative humidity) at ambient temperatures.
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