13709-59-6Relevant articles and documents
Insight into the Crystalline Structure of ThF4 with the Combined Use of Neutron Diffraction, 19F Magic-Angle Spinning-NMR, and Density Functional Theory Calculations
Martel, Laura,Capelli, Elisa,Body, Monique,Klipfel, Marco,Bene?, Ondrej,Maksoud, Louis,Raison, Phillipe E.,Suard, Emmanuelle,Visscher, Lucas,Bessada, Catherine,Legein, Christophe,Charpentier, Thibault,Kovács, Attila
, p. 15350 - 15360 (2018)
Because of its sensitivity to the atomic scale environment, solid-state NMR offers new perspectives in terms of structural characterization, especially when applied jointly with first-principles calculations. Particularly, challenging is the study of actinide-based materials because of the electronic complexity of the actinide cations and to the hazards due to their radioactivity. Consequently, very few studies have been published in this subfield. In the present paper, we report a joint experimental-theoretical analysis of thorium tetrafluoride, ThF4, containing a closed-shell actinide (5f0) cation. Its crystalline structure has been revisited in the present work using powder neutron diffraction experiments. The 19F NMR parameters of the seven F crystallographic sites have been modeled using an empirical superposition model, periodic first-principles calculations, and a cluster-based all-electron approach. On the basis of the atomic position optimized structure, a complete and unambiguous assignment of the 19F NMR resonances to the F sites has been obtained.
INFRARED-TRANSPARENT GLASSES DERIVED FROM THE FLUORIDES OF ZIRCONIUM, THORIUM, AN BARIUM.
Robinson,Pastor,Turk,Devor,Braunstein,Braunstein
, p. 735 - 742 (1980)
Glasses consisting solely of high-purity ZrF//4, ThF//4, and BaF//2 have been synthesized using reactive atmosphere processing (RAP) techniques. RAP of the individual components and molten material with anhydrous HF and CCl//4 is described. The glass molds easily at 312 degree C and 1920 psi with a high-fidelity replication of the die surface. The glass is water-insoluble, unusually hard and strong, and continuously transparent from 0. 3 to 7 mu m.
Raman scattering study of the orthorhombic-to-tetragonal phase transition of a Li3ThF7 crystal
Oliveira,Gesland,Pimenta,Moreira
, p. 9983 - 9989 (1999)
Raman spectroscopy was used to study pulled Li3ThF7 single crystals between 298 and 403 K, using six special backscattering geometries. The observed Raman bands were very broad, owing to the disorder related to the statistical occupancy of the lithium sites (with a 3/4 probability). In spite of this, the symmetry rules are well respected assuming an average model with four lithium ions per chemical formula. The spectral evolutions show a structural phase transition occurring at 368 K. After peak deconvolution, we were able to determine and attribute most of the Raman modes corresponding to each phase. The results are compatible with the proposed orthorhombic (Ccca) to tetragonal (P4/ncc) structural phase transition, whose ferroelastic nature would be responsible for the appearance of an ordered microcracking pattern in this crystal. 1999 The American Physical Society.
Synthesis and nanoscale characterization of (NH4) 4ThF8 and ThNF
Silva, G.W. Chinthaka,Yeamans, Charles B.,Cerefice, Gary S.,Sattelberger, Alfred P.,Czerwinski, Kenneth R.
, p. 5736 - 5746 (2009)
Synthesis of (NH4)4ThF8 by a solid state reaction of ThO2 and NH4HF2 and the formation of ThNF by ammonolysis of (NH4)4ThF8 and ThF4 under differ
Development of a YF3:ThF4 membrane for the possibility of determining fluoride
Gnanasekar, K. I.,Jayaraman, V.,Lakshmi K, Usha,Lakshmigandhan, I.,Ravindranath, Nair Afijith
, (2021)
Preparation of yttrium substituted thorium fluoride (YTF) solid solution, YxTh1?xF4?x (x = 0 – 0.15) by fluorinating a stoichiometric ratio of yttria (Y2O3) and thoria (ThO2) with ammonium hydrogen difluoride (NH4HF2) was acheived. The maximum solubility of YF3 in ThF4 was observed to be 15 mol %. All three compositions of YxTh1?xF4?x (x = 0 – 0.15) solid solution showed an enhanced ionic conductivity over ThF4. 5 mol % yttrium substituted ThF4 (5-YTF) had the highest ionic conductivity, almost 2 orders higher than ThF4. The F? ion selective electrode was designed and tested for estimation of fluoride ion in solution (10?1M to 10?5 M). 5-YTF had the highest sensitivity of 40.0 ± 4 mV/decade in the linear range of 10?1 M to 10?4 M. All the three sensors compositions 5, 10 and 15-YTF have sub Nerstian behavior which is attributed to strong OH? ion interefenece.The results were compared with commercial fluoride ISE (Eu: LaF3).
Joint solubility of PuF3 and CeF3 in ternary melts of lithium, thorium, and uranium fluorides
Lizin, A. A.,Tomilin, S. V.,Osipenko, A. G.,Kormilitsyn, M. V.,Nezgovorov, N. Yu.,Ignat'Ev, V. V.
, p. 36 - 42 (2015)
Joint solubility of PuF3 and CeF3 in melts of the molar composition 78LiF-7ThF4-15UF4 and 72.5LiF-7ThF4-20.5UF4 in the temperature range 550°-800°C was studied. Anhydrous PuF3 and CeF3 spiked with 144Ce, and also anhydrous ThF4 were synthesized. Isothermal saturation method was used for studying the solubility of pressed PuF3 and CeF3 pellets in these melts in an inert (argon) atmosphere. The dependence of the joint solubility of PuF3 and CeF3 on the melt temperature was determined.
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 (2017/06/05)
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.
