Study of the thermal decomposition of the Nd(III), Eu(III) and Tb(III) scorpionates.

Abstract

The thermal behavior of the compounds [κ3HB(N2C3H3)3]3Ln (Ln=Nd, Eu and Tb) was investigated through TG/DTG and DSC analyses. TG/DTG experiments were performed in a TGA-50 Shimadzu instrument under dynamic air atmosphere (50 ml min−1). DSC measurements were performed in a dynamic nitrogen atmosphere (50 ml min−1) at 10 °C min−1 heating rate using a DSC-50 Shimadzu differential calorimeter. For the TG/DTG and DSC analyses, an amount of 1.5–2.0 mg was used. From the TG curves, it was possible to show that all compounds are anhydrous, a one-step mass loss occurring between 200 and 450 °C, yielding a residual stable up to 900 °C. From the DTG curves it was found that decomposition temperatures decrease as the Ln(III) ionic radius decreases. DSC curves indicate that the compounds do not melt before the decomposition. For all three compounds, the decomposition process is exothermic.