The effect of defect structure due to doping and irradiation on the thermal decomposition of potassium chlorate

Abstract

The thermal decomposition of potassium chlorate was investigated as a function of doping and there seems to be a correlation between the polarizing nature of the dopant cation and the thermal degradation temperature of potassium chlorate. In particular, transition metal cations influence strongly the temperature of decomposition. Irradiation and mechanical shock defects influence also the process. A possible mechanism in terms of the semi-conductive properties of the defective chlorates is discussed.Chlorine oxy-salts are subject to thermal decomposition at relatively low temperatures. Their thermal stability depends on various conditions. In particular, the coordinative saturation of the oxygen surrounding the chlorine atom within the complex anions and the nature of the cations seem to determine the outcome of the thermal decomposition of these salts.Thus, the thermal stability decreases apparently from the perchlorates to the chlorates to the chlorites and hypochlorites [1,2], since only the chlorine atom in the perchlorate anions is coordinatively saturated with four oxygen atoms. Also, bonding energies between the central chlorine and the surrounding oxygens decrease quantummechanically in that order [3].On the other hand, the nature of the cations of an oxy-chlorine compound affects significantly the stability and reaction path [4,5], In fact, there seems to be a distinct correlation between the polarizing power of the cations [6] or the ionic character of the cation-oxychlorine bond [7,8] and the thermal stability. The less ionic the bond, or the stronger the polarization power of the cation, the less stable is the compound.The apparent heterogeneous catalytic effects of metal oxides on the solid state and molten phase decomposition of potassium chlorate and perchlorate have been studied previously [9], and it was found that the defect nature of the metal oxides played an important part in the catalytic efficiency with respect to the thermal decomposition of the chlorates and perchlorates [10].As a logical consequence of these studies we investigated the influence which intra-crystalline defects such as cationic impurities might have on the thermal decomposition of potassium chlorate. To this end, chlorate samples were prepared

Catalytic effects of nonoxide metal compounds on the thermal decomposition of sodium chlorate

“…It is reported that sodium dichromate catalyzes the decomposition of KCIO3 (Udupa, 1981). It is also reported that when FeCls and CuCl2 were doped into KCIO3, the decomposition temperature of KCIO3 decreased significantly (Rudloff and Freeman, 1980). This may also be a catalytic effect rather than an effect of doping, because no structural changes were detected by X-ray diffraction analysis, and the chlorides have very different crystal structure from KCIO3.…”