TEMPERATURE-RESOLVED X-RAY-POWDER DIFFRACTOMETRY OF A NEW CADMIUM HYDROXIDE NITRATE

A new cadmium hydroxide nitrate, Cd3(OH)5NO3, was prepared by an interdiffusion method and its X-ray powder diffraction pattern was indexed. The symmetry is orthorhombic and the cell parameters are a = 3.4209(3)Å, b = 10.0292(6)Å, and c = 11.0295(6)Å. The thermal decomposition of this solid was analyzed in a vacuum and in a nitrogen atmosphere by the TG, MS, and TRXD methods. Temperature-resolved diffractometry was carried out by means of a curved position-sensitive detector combined to a conventional X-ray powder diffractometer. A new modification of Cd(OH)NO3 was displayed during the first stage of the decomposition and a detailed decomposition scheme is proposed. This study shows that the rate of the structural transformation can be quite different from that of the departure of the gaseous molecules. From TRXD, the evolution of microstructural properties of Cd(OH)NO3 and CdO as a function of temperature is also described. © 1990.