Uranium hexafluoride

Uranium hexafluoride (), (sometimes called "hex") is an inorganic compound with the formula UF6. Uranium hexafluoride is a volatile white solid that reacts with water, releasing corrosive hydrofluoric acid. The compound reacts mildly with aluminium, forming a thin surface layer of AlF3 that resists any further reaction from the compound. UF6 is used in the process of enriching uranium, which produces fuel for nuclear reactors and nuclear weapons. Milled uranium ore—U3O8 or "yellowcake"—is dissolved in nitric acid, yielding a solution of uranyl nitrate UO2(NO3)2. Pure uranyl nitrate is obtained by solvent extraction, then treated with ammonia to produce ammonium diuranate ("ADU", (NH4)2U2O7). Reduction with hydrogen gives UO2, which is converted with hydrofluoric acid (HF) to uranium tetrafluoride, UF4. Oxidation with fluorine yields UF6. The Honeywell Uranium Hexafluoride Processing Facility uses a different process. During nuclear reprocessing, uranium is reacted with chlorine trifluoride to give UF6: U + 2 ClF3 → UF6 + Cl2 At atmospheric pressure, sublimates at 56.5 °C. The solid-state structure was determined by neutron diffraction at 77 K and 293 K. File:Uranium-hexafluoride-unit-cell-3D-balls.png|[[Ball-and-stick model]] of the unit cell of uranium hexafluorideJ. C. Taylor, P. W. Wilson, J. W. Kelly: „The structures of fluorides. I. Deviations from ideal symmetry in the structure of crystalline UF6: a neutron diffraction analysis", ''[[Acta Crystallogr.]]'', '''1973''', ''B29'', p. 7–12; {{doi|10.1107/S0567740873001895}}. File:Uranium hexafluoride dimensions.svg|Bond lengths and angles of gaseous uranium hexafluoride{{cite journal |last1=Kimura |first1=Masao |last2=Schomaker |first2=Werner |last3=Smith |first3=Darwin W. |last4=Bernard |year=1968 |title=Electron‐Diffraction Investigation of the Hexafluorides of Tungsten, Osmium, Iridium, Uranium, Neptunium, and Plutonium |url=https://authors.library.caltech.edu/71173/ |journal=[[J. Chem. Phys.