10049-14-6Relevant articles and documents
Vibrational properties of uranium fluorides
Miskowiec, Andrew,Shields, Ashley E.,Niedziela,Cheng, Yongqiang,Taylor, Paul,DelCul, Guillermo,Hunt, Rodney,Spencer, Barry,Langford, John,Abernathy, Douglas
, p. 194 - 205 (2019)
Multiphase mixtures of the uranium fluoride compounds UFx with x = 3, 4, 4.5, 5, whose local U–F bonding geometry is conserved, may result from UF6 reduction. One method for identifying multiphase mixtures is optical vibrational spectroscopy, b
Thermochemical properties of the gaseous lower valent fluorides of uranium
Lau, K. H.,Hildenbrand, D. L.
, p. 2646 - 2652 (1982)
High temperature gaseous equilibria involving the lower-valent uranium fluorides UF, UF2, UF3, and UF4 were studied by mass spectrometry, and reaction enthalpies and entropies with estimated uncertainties of +/-2 kcal/mol and +/-2 cal/deg mol were derived solely from the temperature coefficients of reaction equilibrium constants.These results yield the following bond dissociation energies at 298 K in kcal/mol: Do(F3U-F) = 148.2; Do(F2U-F) = 149.0; Do(FU-F) = 136.5; and Do(U-F) = 157.5.The sum of these values is compatible with the heat of atomization of UF4(g) evaluated from independent source.A value of Do(F3U-F) derived from electron impact measurements agrees well with the equilibrium data.The reaction entropy data indicate that the electronic entropies of UF, UF2, and UF3 are comparable to that of atomic uranium in the same temperature range, and provide a basis for estimating the total thermodynamic functions of these species.Experimental entropies obtained for UF4 indicate the likelihood of a distorted tetrahedral structure of effective C2v symmetry.The results provide sufficient information for predicting the equilibrium composition of the gaseous U-F system over a wide temperature range.
Uranium tetrafluoride production using the dropping mercury electrode
Dides, Munir,Hernández, José,Olivares, Luis
, (2021)
This work shows the technical feasibility to obtain uranium tetrafluoride through an electrochemical process using a dropping mercury electrode. This product was obtained from ammonium diuranate, dissolved in hydrofluoric solutions, using concentrations of 50 g/L UO2F2. The system was evaluated with current intensities densities from 1.6 to 6.3 A and temperatures from 25 to 65 °C. The maximum current efficiency achieved was 95 %. The UF4 powders achieved spherical morphology, with diameters between 40–60 μm. This property allows correct compaction for the subsequent production of metallic uranium, which allows reaching high-density UF4 – Mg mixtures, between 3.0–3.5 g/cm3, as it was proven in our previous studies. This technique achieved this result thanks to the electrochemical properties of the mercury, when used as cathode. The impurity levels of this product obtained by electrolysis are only those that come from the initial ammonium diuranate concentrates. This method is an alternative to the classic process of UF4 precipitation in an aqueous medium using reducing agents, as the conventional stannous chloride (SnCl2), which commonly contaminate uranium compounds.
Hydrazinium(+2) and hydroxylammonium hexafluorouranates(V)
Frlec, Boris,Hyman, Herbert H.
, p. 2233 - 2239 (1967)
In the reaction between uranium hexafluoride and hydrazinium(+2) fluoride in liquid hydrogen fluoride at room temperature, with excess uranium hexafluoride, the product is hydrazinium(+2) bishexafluorouranate(V), N2H6(UF6)
Preparation and Characterization of the Adduct Uranium Pentafluoride-Arsenic-Pentafluoride (1/1)
Gantar, Darja,Frlec, Boris
, p. 2345 - 2346 (1984)
The system UF5-AsF5, UF6-AsF5-UF4, and UF4-AsF5-F2 were studied using anhydrous HF as a solvent.In all cases a dark blue solution results from which blue crystals of composition UF5.AsF5 were isolated at temperatures lower than -30 deg C.At room temperature thermal decomposition of the adduct takes place giving AsF5 vapour, and a solid residue which was identified as β-UF5.
Separation and recovery study of uranium from spent NaF (fillers)
Amamoto, Ippei,Terai, Takayuki,Oobayashi, Hiroshi,Fujita, Reiko
, p. 602 - 607 (2005)
The molten salt technique is considered to be a feasible technique applicable for the removal of uranium from the spent NaF (fillers). Simple spent NaF or NaF with NaCl, i.e. mixed salt, was used as an electrolyte and the uranium concentrations in the bath, pre-treatment condition, electrolytic temperature, current density, etc. were given as parameters in this experiment. Results from the fundamental experiments showed the potential applicability of the molten salt technique for the removal of uranium from spent NaF.
Some Reactions of Uranium Chloride Pentafluoride
Downs, Anthony J.,Gardner, Christopher J.
, p. 1289 - 1296 (1986)
The molecule UF5Cl has been isolated, together with an excess of UF6, in a solid matrix of Ar, N2, or CO and characterised by its i.r. spectrum.Under these conditions it dissociates under the action of radiation having wavelengths close to 500 nm to give UF5; OCCl radical and OCClF are also formed on photolysis in a solid CO matrix, whereas a species believed to be U2F11 is formed on photolysis in a solid N2 matrix.CCl3F solutions of fluoride-rich mixtures of uranium(VI) chloride fluorides have been shown to function as chlorinating, fluorinating, or chlorofluorinating reagents in their reactions with various unsaturated molecules at temperatures low enough to preclude thermal decomposition of the mixed halides ( -60 deg C).
Direct conversion of uranium dioxide UO2 to uranium tetrafluoride UF4 using the fluorinated ionic liquid [Bmim][PF6]
Joly, Florian,Simon, Pardis,Trivelli, Xavier,Arab, Mehdi,Morel, Bertrand,Solari, Pier Lorenzo,Paul, Jean-Francois,Moisy, Philippe,Volkringer, Christophe
, p. 274 - 278 (2020)
The industrial fluorination of UO2 to UF4 is based on a complex process involving the manipulation of a large amount of HF, a very toxic and corrosive gas. We present here a safer way to accomplish this reaction utilizing ionic liqui
REACTION BETWEEN URANIUM HEXAFLUORIDE AND TRIMETHYLSILYLHALIDES.
Brown,Berry,Holloway,Staunton
, p. 149 - 153 (1983)
Reaction involving 1. 1:1 molar ratios of uranium hexafluoride to either trimethylsilylchloride or trimethylsilylbromide in halocarbon solutions yield beta -UF//5 at room temperature. With 2 mol equivalents of trimethylsilylchloride the product is UF//4.
The reactions of uranium hexafluoride with hydrogen sulfide and with carbon disulfide
Trevorrow,Fischer, Jack,Gunther
, p. 1281 - 1284 (1963)
Uranium hexafluoride reacts with hydrogen sulfide at 25° to produce uranium tetrafluoride, sulfur tetrafluoride, and hydrogen fluoride. Uranium hexafluoride reacts with carbon disulfide vapor at 25° to produce uranium tetrafluoride, sulfur tetrafluoride, bistrifluoromethyl disulfide [(CF3)2S2], and bistrifluoromethyl trisulfide [(CF3)2S3], and at elevated temperatures the reaction also produces sulfur hexafluoride and tetrafluoromethane, CF4. When uranium hexafluoride vapor reacts with carbon disulfide vapor at 25° in the presence of helium as a diluent, the favored perfluoroalkyl product is bistrifluoromethyl trisulfide. Uranium hexafluoride is compared with other metal fluorides with respect to their reactions with carbon disulfide.
