Thermal decomposition of metal N,N-dialkylcarbamates

Thermogravimetric analysis coupled with IR spectroscopy was used to investigate the thermal stability and decomposition products of N,N-dialkylcarbamates of zirconium(IV), hafnium(IV), and niobium(IV), M(O2CNR2)4. The niobium derivatives were less stable than the corresponding Zr(IV) and Hf(IV) derivatives, and the thermal stability was in the order of R = Et > iPr > Me. XRD analysis of the residue showed the formation of the oxides ZrO2 (tetragonal, P4 2 /nmc), HfO2, (monoclinic, P2 1/c), and Nb2O5 (orthorhombic, Pbam). TEM analysis showed that all the oxides were obtained as nanopowders with a crystal size below 30 nm.