High-temperature oxidation of europium (II) sulfide
Denisenko, Yuriy G.; Molokeev, Maxim S.; Krylov, Alexander S.; Aleksandrovsky, Aleksandr S.; Oreshonkov, Aleksandr S.; Atuchin, Victor V.; Azarapin, Nikita O.; Plyusnin, Pavel E.; Sal'nikova, Elena I.; Andreev, Oleg V. Source: JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY, 79 62-70; 10.1016/j.jiec.2019.05.006 NOV 25 2019
The process of high-temperature oxidation of EuS in the air was explored in the temperature range of 500–1000 °C. The oxidation reaction enthalpy was determined (ΔH0exp = −1718.5 kJ/mol). The study of oxidation products allowed to establish the mechanism of EuS oxidation with oxygen. At 500–600 °C, EuS is oxidized to a mixture of Eu3+-containing compounds (Eu3S4, Eu2O2S). In the range of 700–1000 °C, only europium oxysulfate Eu2O2SO4 is formed. The structure refinement for Eu2O2SO4 was performed by the Rietveld method. The luminescence intensity of europium oxysulfate Eu2O2SO4 with characteristic 4f-4f transitions from the 5D0 state was investigated as a function of oxidation temperature.