Cerium tetrafluoride.  II.  The system cerium tetrafluoride-cerium trifluoride

Asker, WJ; Wylie, A. W.

doi:10.1071/ch9650969

Cited by 3 publications

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“…Among other trifluorides of rare earth metals, cerium trifluoride is a nonvolatile compoundits vapor pressure at 1370 K is p °(CeF 3 ) = 8.4 × 10 –2 Pa . Thermodynamic activities of CeF 4 and CeF 3 in their mixture at temperatures lower than 1081 K are equal to 1, so the pressure of cerium tetrafluoride, achieved in the effusion cell, is equal to its saturated vapor pressure, in spite of its partial decomposition with formation and accumulation of CeF 3 (s).…”

Section: Resultsmentioning

confidence: 99%

Cerium Tetrafluoride: Sublimation, Thermolysis, and Atomic Fluorine Migration

et al. 2015

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Saturated vapor pressure p° and enthalpy of sublimation (ΔsH°) of cerium tetrafluoride CeF4 were determined by means of Knudsen effusion mass spectrometry in the range of 750-920 K. It was discovered that sublimation of cerium tetrafluoride from a platinum effusion cell competes with thermal decomposition to CeF3 in the solid phase, but no accompanying release of fluorine to the gas phase occurs. Thus, fluorine atoms migrate within the surface layer of CeF4(s) to the regions of their irreversible drain. We used scanning electron microscopy to study the distribution of the residual CeF3(s) across the inner surface of the effusion cell after complete evaporation of CeF4(s). It was observed that CeF3 accumulates near the edge of the effusion orifice and near the junction of the lid and the body of the cell, that is, in those regions where the fluorine atoms can migrate to a free platinum surface and thus be depleted from the system. Distribution of CeF3(s) solid particles indicates the ways of fluorine atoms migration providing CeF3(s) formation inside the CeF4(s) surface layer.

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Section: Resultsmentioning

confidence: 99%