Thermal behaviour of otavite, CdCO3

The thermal behaviour of otavite, CdCO3, has been investigated from 303 K up to decomposition, which starts at 603 K and is completed, due to kinetics, at 648 K. The dependence of the cell parameters on temperature is peculiar as the a parameter slightly increases up to 453 K and subsequently contracts. Microstrain ε0 follows the same behaviour. The possible occurrence of orientational disorder of the CO3 group has been observed near the decomposition temperature Td. However, the partial superposition of Bragg reflections of otavite and its decomposition product, CdO, coupled to fast kinetics, lead to less accurate structural parameters near Td, requiring confirmation of such result.