Trends in stability of rare earth pyrochlores in the lanthanide series: Ruthenium

Abstract

Stability of lanthanide pyrochlores is important as they are proposed as rad-waste matrices. The molar Gibbs energy of formation data obtained was correlated with increase in atomic number down the lanthanide series for Ln2Ru2O7 where (Ln = Nd, Sm, Eu, Gd, Ho-Lu &Y). The enthalpies of formation of the ternary oxides from their component binary oxides at T/K = 298.15 were determined. The enthalpies of formation from oxides become less negative down the lanthanide series as the radius ratio Ln/Ru decreases. These thermodynamic data can be correlated to pyrochlores ability to withstand irradiation damage, an important input for the nuclear industry.