Influence of SO 4 2− doping and Y-irradiation on the thermal decomposition of barium bromate

Abstract

The effects of SOl-doping and Y-irradiation on the isothermal (563 K) decomposition of barium bromate have been investigated gasometrically with a vacuum apparatus. Plots of the fraction decomposed a vs. time t for pure, doped and irradiated crystals exhibited characteristic stages: initial gas evolution (initial puff), an induction perioc~, linear reaction, an acceleratory period and decay. The data are considered in the light of various kinetic models, e.g. linea~" rate equation, ProutLTompkins and Avrami-Erofecv. The plausible mechanism of the reaction and the effects on this .of anion vacancies and Y-irradiation are discussed briefly.The thermal decomposition of solids is an important field of solid-state chemistry, with vast technical applications [1,2]. The understanding and control of the chemical reactivity of solids are the main objects in decomposition studies [3]. As ammonium perchlorate (AP) is extensively used as a solid propellant and more generally in pyrotechnic systems [4], a detailed study is needed on the decomposition of inorganic oxyanions such as chlorates, bromates and perchlorates, and on how this is influenced by vacancies (cation and anion) and irradiation. Barium bromate, which decomposes entirely in the solid phase, was chosen for the present study. Although the effects of cation vacancies and Y-irradiation on the decomposition of its crystals have been well studied [5][6][7][8], the available data on the effects of anion vacancies are inadequate. The present investigation relates to the effects of SO~-doping and y-irradiation on the isothermal decomposition of barium bromate. ExperimentalBarium bromate was prepared from AR grade chemicals and was purified by repeated recrystallization. Doped (SO~-, 1.0 mol%) crystals of barium bromate

Role of γ-irradiation and Ba2+ doping on the isothermal decomposition of caesium bromate

“…Though bromide generated in the beginning of the reaction, catalyse [15] the decomposition, after certain time interval when appreciable amount of the former is deposited results decelaration. The former phenomenon may be attributed to catalytic effect whereas the later to cage effect, i.e., CsBr, deposited over the caesium bromate crystals act as a barrier for the further decomposition to proceed.…”

Simultaneous Determination of 234Th and 228Th in Environmental Samples using Cerenkov Counting

“…It is reasonable to assume that bromide ion is instrumental in catalysing the decomposition of bromate as it acts as electron donor and attracts oxygen atoms from neighbouring bromate ions resulting bromite and hypobromite which would almost certainly decompose spontaneously and independently. The mechanism [31,32] can be represented as:…”