MAGNITUDES OF ARRHENIUS PARAMETERS FOR DECOMPOSITION REACTIONS OF SOLIDS

The Polanyi-Wigner theory of rates of solid state reactions and the transition state theory indicate a preferred value of approx. 10(12) s(-1) for the Arrhenius reaction frequency factor A. To investigate whether this value is preferred amongst the reported kinetic results in the literature, some 404 similar sets of activation energy (E) and A values have been compared, including results for a wide range of different solid state decompositions. Plots of the relative numbers of reactions having different magnitudes of A showed a slightly preferred value between 10(11) < A < 10(13) s(-1). This weak preference did not offer strong support to the general applicability of the Polanyi-Wigner model. Similarly, E values were fairly evenly distributed between 100 and 230 kJ mol(-1), without a dominant value. There was no evidence of compensation behaviour.