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
Russell, E. R.,Hyder, M. L.
, p. 175 - 178 (1977)
Tomlinson, L.,Morrow, S. A.,Graves, S.
, p. 1008 - 1018 (1961)
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)
Roy, K. N.,Prasad, Rajendra,Bhupathy, M.,Venugopal, V.,Singh, Ziley,Sood, D. D.
, p. 333 - 338 (1981)
Catalano, E.,Barletta, R. E.,Pearson, R. K.
, p. 3291 - 3299 (1979)
Kompa, K. L.,Parker, J. H.,Pimentel, G. C.
, p. 4257 - 4264 (1968)
Yahata, T.,Muromura, T.,Ouchi, K.,Naito, K.
, p. 3339 - 3343 (1971)
Kelmers, A. D.,Bennett, M. R.
, p. 333 - 337 (1976)
Frlec, B.
, p. 2112 - 2117 (1967)
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.
Synthesis of UF4 and ThF4 by HF gas fluorination and re-determination of the UF4 melting point
Sou?ek, Pavel,Bene?, Ond?ej,Claux, Benoit,Capelli, Elisa,Ougier, Michel,Tyrpekl, Václav,Vigier, Jean-Francois,Konings, Rudy J.M.
, p. 33 - 40 (2017)
Basic thermodynamic and electrochemical data of pure actinide fluorides and their mixtures are required for the design and safety assessment of any presently studied molten salt reactor concept based on molten fluoride salt fuel. Since the actinide fluorides are usually not produced commercially, they have to be prepared from the available input materials, typically oxides. In this work, a specially designed facility for synthesis of pure actinide fluorides using pure HF gas is described, as well as a complete procedure of synthesis and characterisation of pure UF4 and ThF4. The fluorination installation consists of a glove box kept under a purified argon atmosphere, a high temperature horizontal fluorination reactor and a HF supply gas line connected to the glove box. The fluorides were synthesised from high specific surface oxides prepared from the respective oxalates by low temperature calcination. The fluorination was partly stationary and partly in a HF gas flow, based on a heterogeneous powder-gas reaction at high temperatures. The products were characterised by X-ray diffraction and differential scanning calorimetry, which confirmed high purity products obtained by this method. Moreover, the melting point of UF4 was revised using a pure sample and a new value is suggested.
Two- and three-dimensional open-framework uranium arsenates: Synthesis, structure, and characterization
Rao, V. Koteswara,Bharathi,Prabhu, Ramanath,Chandra, Manabendra,Natarajan, Srinivasan
, p. 2931 - 2947 (2010)
Hydrothermal reactions between uranium salts and arsenic pentoxlde in the presence of two different amines yielded six new uranium arsenate phases exhibiting open-framework structures, ethylenedlamine (en): [C2N 2H9][(UO2)(AsO4)], I; [C 2N2H10][(UO2)F(HAsO 4)]2-4H2O, II; [C2N 2H9][U2F5(HAsO4)J, III; [C2N2H9][UF2(AsO4)], IV; diethylenetriamine (DETA), [C4N3H16][U 2F3(AsO4)2(HAsO4)], V; and [C4N3H16][U2F 6(AsO4)(HAsO4)], Vl. The structures were determined using single crystal studies, which revealed two- (I, II, V) and three-dimensional (III, IV, Vl) structures for the uranium arsenates. The uranium atom, in these compounds, exhibits considerable variations In the coordination (6 to 9) that appears to have some correlation with the synthetic conditions. The water molecules in [C2N2H 10][(UO2)F(HAsO4)]2-4H2O, II, could be reverslbly removed, and the dehydrated phase, [C2N 2H10][(UO2)F(HAsO4)]2, IIa, was also characterized using single crystal studies. The observation of many mlneralogical structures In the present compounds suggests that the hydrothermal method could successfully replicate the geothermal conditions. As part of this study, we have observed autunite, Ca[(UO2)(PO 4)]2(H2O)11; metavauxite, [Fe(H 2O)6][Al(OH)(H2O)(PO4)] 2, linarite, PbCu(SO4)(OH)2, and tancoite, LiNa2H[Al(PO4)2(OH)], structures. The repeated observation of the secondary building unit, SBU-4, In many of the uranium arsenate structures suggests that these are viable building units. Optical studies on the uranium arsenate compound, [C4N3H 16][U2F6(AsO4)(HAsO4)], Vl, containing uranium In the +4 oxidation state Indicates a blue emission through an upconverslon process. The compound also exhibits antlferromagnetic behavior.
Spectroscopic properties of K5Li2UF10
Karbowiak,Gajek,Drozdzyński
, p. 239 - 248 (2005)
A new uranium (III) fluoro-complex of the formula K5Li 2UF10 has been synthesised and characterised by X-ray powder diffraction and electronic absorption spectra measurements. The compound crystallises in the orthorhombic system, space group Pnma, with a = 20.723, b = 7.809, c = 6.932 ?, V = 1121.89 ?3, Z = 4 and is isostructural with its K5Li2NdF10 and K 5Li2LaF10 analogous. The absorption spectrum of a polycrystalline sample of K5Li2UF10 was recorded at 4.2 K in the 3500-45,000 cm-1 range and is discussed. The observed crystal-field levels were assigned and fitted to parameters of the simplified angular overlap model (AOM) and next to those of a semi-empirical Hamiltonian, which was representing the combined atomic and one-electron crystal-field interactions. The starting values of the AOM parameters were obtained from ab initio calculations. The analysis of the spectra enabled the assignment of 71 crystal-field levels of U3+ with a relatively small r.m.s. deviation of 37 cm-1. The total splitting of 714 cm -1 was calculated for the 4I9/2 ground multiplet.
UF4 and the High-Pressure Polymorph HP-UF4
Scheibe, Benjamin,Bruns, J?rn,Heymann, Gunter,Sachs, Malte,Karttunen, Antti J.,Pietzonka, Clemens,Ivlev, Sergei I.,Huppertz, Hubert,Kraus, Florian
, p. 7366 - 7374 (2019)
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 powde
Bennett, M. R.,Ferris, L. M.
, p. 1285 - 1290 (1974)
Preparation and properties of several ammonium uranium(IV) and ammonium plutonium(IV) fluorides
Benz,Douglass,Kruse,Penneman
, p. 799 - 803 (1963)
A series of anhydrous fluoride complexes is formed between NH4F and actinide tetrafluorides. Compounds with NH4F : MF4 (M = U or Pu) mole ratios of 4:1, 2:1, 7:6, 1: 1, and 1:3 were prepared by reaction of stoichionictric quantities in sealed tubes or by gravimetric arrests during NH4F distillation. X-Ray powder diffraction data are presented. Corresponding U(IV) and Pu(IV) compounds are isostructural. The 7NH4F·6MF4 compounds are rhombohedral, a0 = 9.55 and 9.42 A?., α = 107.4° and 107.4° for M = U and Pu, respectively. A method of chemical analysis for NH4, U, and F on a single sample was developed using pyrohydrolysis, ion exchange, and volumetric techniques.
Standard enthalpies of formation of uranium compounds VII. UF3 and UF4 (by solution calorimetry)
Cordfunke, E. H. P.,Ouweltjes, W.
, p. 193 - 198 (1981)
Enthalpies of solution of UF3 and UF4 in a mixed aqueous solvent containing sulphuric acid, boric acid, and ceric sulphate have been measured calorimetrically.Together with measurements of the enthalpy of solution of γ-UO3 and U3O8 in the same solution, the standard enthalpies of formation of solid UF3 and UF4 have been derived: SDH0f(UF3, s, 298.15 K) = -(1508.5 +/- 5.5) kJ mol-1; SDH0f(UF4, s, 298.15 K) = -(1920.0 +/- 3.7) kJ mol-1.The values differ considerably from literature values.
Gogolev,Shilov,Perminov,Fedoseev
, (2017)
Preparation and Characterization of U2O2F7
Asada, Kameo,Ema, Keiko,Iwai, Takashi
, p. 3189 - 3194 (1987)
Reaction of UO2F2 with UF5 at 400 deg C under UF6-pressure of 3 atm followed by evaporation of excess UF5 has yielded a greenish white residue.Its X-ray diffraction pattern and infrared spectrum are sufficiently unique to establish that this material is a true compound.Its chemical formula has been shown to be U2O2F7, on the grounds of chemical analysis and thermal decomposition.The oxygen content was determined directly by means of 18O isotopic dilution method based on the combustion of the samples with BrF5.