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Author Denisenko, Yu. G. ♦ Khritokhin, N. A. ♦ Andreev, O. V. ♦ Basova, S. A. ♦ Sal’nikova, E. I. ♦ Polkovnikov, A. A.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY ♦ EUROPIUM SULFATES ♦ FORMATION HEAT ♦ INERT ATMOSPHERE ♦ KINETICS ♦ PYROLYSIS ♦ TEMPERATURE DEPENDENCE ♦ TEMPERATURE RANGE ♦ THERMAL ANALYSIS
Abstract Reactions of europium sulfates Eu{sub 2}(SO{sub 4}){sub 3}·8H{sub 2}O and EuSO{sub 4} complete decomposition were studied by Simultaneous Thermal Analysis. It was revealed that one-step dehydratation of Eu{sub 2}(SO{sub 4}){sub 3}·8H{sub 2}O crystallohydrate is accompanied by the formation of amorphous anhydrous europium sulfate Eu{sub 2}(SO{sub 4}){sub 3}. Crystallization of amorphous europium (III) sulfate occurs at 381.1 °C (in argon) and 391.3 °C (in air). The average enthalpy values for dehydratation reaction of Eu{sub 2}(SO{sub 4}){sub 3}·8H{sub 2}O (ΔH° = 141.1 kJ/mol), decomposition reactions of Eu{sub 2}(SO{sub 4}){sub 3} (ΔH = 463.1 kJ/mol), Eu{sub 2}O{sub 2}SO{sub 4} (ΔH = 378.4 kJ/mol) and EuSO{sub 4} (ΔH = 124.1 kJ/mol) were determined. The step process mechanisms of thermal decomposition of europium (III) sulfate in air and europium (II) sulfate in inert atmosphere were established and justified. The kinetic parameters of complete thermal decomposition of europium (III) sulfate octahydrate were calculated by Kissinger model. The standard enthalpies of compound formation were calculated using thermal effects and formation enthalpy data for binary compounds. - Highlights: • The temperature ranges of thermal stability of europium sulfates in different atmospheres were defined. • The causes of appearance of exothermic effects in DSC-analysis processes were determined. • The thermodynamic and kinetic parameters of sulfates thermal destruction were defined. • The standard formation enthalpies of europium sulfates were calculated.
ISSN 00224596
Educational Use Research
Learning Resource Type Article
Publisher Date 2017-11-15
Publisher Place United States
Journal Journal of Solid State Chemistry
Volume Number 255


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