Cerium Tetrafluoride: Sublimation, Thermolysis, and Atomic Fluorine Migration

Chilingarov, N. S.; Knotko, A. V.; Shlyapnikov, Igor M.; Mazej, Zoran; Kristl, Matjaž; Sidorov, Lev N.

doi:10.1021/acs.jpca.5b04105

Cited by 13 publications

(13 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Moreover, the conditions under which CeF 4 converted to CeF 3 in different reaction vessels were not completely the same. 12 The decomposition proceeds with the elimination of molecular fluorine, according to the following equation ( eq 4 ) 29 In this work, the platinum crucible reactor was used and the temperature should be controlled below 1114 K.…”

Section: Resultsmentioning

confidence: 99%

Synthesis of Cerium Tetrafluoride and Cerium Trifluoride Nanoscale Polycrystals from Ammonium Hydrogen Difluoride

et al. 2021

View full text Add to dashboard Cite

This paper reported a dry synthesis and characterization of cerium tetrafluoride (CeF 4 ) and cerium trifluoride (CeF 3 ) nanoscale polycrystals (NPs). The CeF 4 NPs were spherical or flaky and approximately 10 ± 2 nm in diameter. The CeF 3 NPs were rod-shaped nanorods with a length of about 150 ± 5 nm and a diameter of about 20 ± 2 nm. The first step was to synthesize the intermediate product—(NH 4 ) 4 CeF 8 by mixing CeO 2 and NH 4 HF 2 at a molar ratio of 1:6 at 390 K. The structural characterization was analyzed by X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). Then, (NH 4 ) 4 CeF 8 was heated in an argon gas flow to synthesize the CeF 3 and CeF 4 NPs. The products were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). The properties of CeF 3 and CeF 4 NPs were further evaluated by transmission electron microscopy (TEM), selected area electron diffraction pattern (SAED), and high-resolution transmission electron microscopy (HRTEM). The findings provided an alternative strategy for the synthesis of nanometer fluorides, which could be a reference for high-performance research on other nanometer fluorides.

show abstract

Section: Resultsmentioning

confidence: 99%

Synthesis of Cerium Tetrafluoride and Cerium Trifluoride Nanoscale Polycrystals from Ammonium Hydrogen Difluoride

et al. 2021

View full text Add to dashboard Cite

show abstract

“…Recently, an unusual behavior of cerium tetrafluoride during its sublimation from the Knudsen platinum cell was discovered . The effusion beam, leaving the chamber, consisted of CeF 4 molecules only, and there were no other fluorides as well as atomic and molecular fluorine.…”

Section: Resultsmentioning

confidence: 99%

“…Another case is observed, when the sublimation of CeF 4 or FeF 3 takes place from a platinum effusion cell that is tightly inserted into a steel or nickel holder. In both cases, there is a negligible amount of atomic or molecular fluorine in the gas phase.…”

Section: Resultsmentioning

confidence: 99%

“…Experimental studies of the interaction of atomic fluorine with metallic platinum surfaces were carried out using the Knudsen effusion method with mass spectral registration of the evaporative products. A detailed description is given in ref . A nickel Knudsen effusion cell 12 mm in height, inner diameter of 8 mm, and an effusion orifice of 9.6 × 10 –2 mm 2 in area was used as a reactor.…”

Section: Experimental Sectionmentioning

confidence: 99%

“…The peculiarity of this source of atomic fluorine is that there are two ways of moving atoms into the reaction zone. Surface diffusion is added to transfer through the gas phase; atomic fluorine can move along the surface of the carrier toward the object of fluorination (heterogeneous remote fluorination), and in some cases, the diffusion path proves to be more effective than the gas-phase path. , …”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Remote Fluorination by Spillover of Atomic Fluorine

et al. 2018

View full text Add to dashboard Cite

The phenomenon of atomic fluorine spillover was studied by comparing fluorination of an isolated platinum plate and of one welded to a nickel plate. Fluorination through the gas phase was performed by atomic fluorine generated by thermal decomposition of spatially separated TbF 4 . The reactions were carried out in a Knudsen effusion cell and monitored mass spectrometrically with subsequent microscopic investigation of the fluorinated Pt and Ni surfaces. We demonstrate that the contact with Ni strongly enhances the rate of Pt fluorination because of additional influx of adsorbed fluorine atoms across the nonstoichiometric NiF 2−x layer that forms on the Ni surface. Related earlier studies with iron and cerium tri-and tetrafluorides suggest that diffusion of atomic fluorine to the zone of its final consumption (e.g., Pt) across vacancy-rich intermediary surface layers of transition-metal fluorides is a common phenomenon. Furthermore, such layers appear to suppress atomic fluorine recombination. We compare our present findings with the literature data on the spillover of hydrogen and oxygen.

show abstract

Development of the High‐Temperature Knudsen Effusion Mass Spectrometry in the Nordic Countries

Stolyarova,

Shilov,

Vorozhtcov

2024

steel research int.

View full text Add to dashboard Cite

In this article, a brief review of the development of the Knudsen effusion mass spectrometric (KEMS) approach in the Theoretical Metallurgy Department of the KTH Royal Institute of Technology and in the in the Laboratory of Metallurgy of the Helsinki University of Technology and modifications of quadrupole model QMG420 mass spectrometers, is presented. The thermodynamic data obtained from vaporization of standards, such as NaCl, CsCl, B2O3, and Ag, and of the B2O3–Al2O3 and ZnO–P2O5 systems is compared with the data obtained using a magnetic MS1301 mass spectrometer. For the first time, composition of the vapor phase over the Dy2O3–DyF3, CaO–CaCl2, and Cu–Mg systems and the partial pressures of components at high temperatures are investigated. The experimental data obtained for the investigated systems are used for prediction of the vaporization processes and modeling of thermodynamic properties and high‐temperature phase equilibria in the multicomponent systems used in metallurgy. An account is given of the detailed studies of the vaporization processes and thermodynamic properties of some multicomponent systems composed of oxides, fluorides, and carbonates forming mold powders for continuous casting of steel. Some new directions of the ongoing studies by the KEMS method are summarized.

show abstract

Cerium Tetrafluoride: Sublimation, Thermolysis, and Atomic Fluorine Migration

Cited by 13 publications

References 16 publications

Synthesis of Cerium Tetrafluoride and Cerium Trifluoride Nanoscale Polycrystals from Ammonium Hydrogen Difluoride

Synthesis of Cerium Tetrafluoride and Cerium Trifluoride Nanoscale Polycrystals from Ammonium Hydrogen Difluoride

Remote Fluorination by Spillover of Atomic Fluorine

Development of the High‐Temperature Knudsen Effusion Mass Spectrometry in the Nordic Countries

Contact Info

Product

Resources

About