Equilibrium of EuS with Gas Mixtures of H₂S,H₂ and CO₂

Abstract

EuS and EU2O3 powder samples were equilibrated with H2S-H2-CO2 gas mixtures in the temperature range 700-1500 °C. Since the sulfur and oxygen fugacities of the gas mixtures -as calculated from thermodynamic data -can vary by about 10 7 , EuS of different stoichiometrics may be produced. At higher oxygen and lower sulfur fugacities EuS is oxidized to EU2O2S. The border line between the two phases can be fitted by the equation log(/(S2)/atm.) = 2 log(/(02)/ atm.) + 48300/7' -9.3 and compared to border lines of other phases of the Eu-O-S system, which can be calculated from thermodynamic data.