Determination of solid state basicity of rare earth oxides by thermal analysis of their carbonates

Relative basicities of the rare earth oxides (M2O3) were determined from the measurement by TG - DTA of decomposition temperatures of the carbonates of Ce, Pr, Sm, Eu, Gd, Tb, Dy, Ho, Er and Yb. From the comparison of this data with that published by Head and Holley, a sequence of basicity has been proposed for the entire range of rare earth oxides. This sequence in decreasing basicities is: La > Pr ~ Nd > Sm > Gd ~ Eu > Tb ~ Ho ~ Er > Dy ∼ Tm ∼ Yb ∼ Lu > Ce. Basicity of rare earth oxides, therefore, does not decrease progressively with an increase in atomic number.