Activation energy chromate decomposition

The kinetics of the ammonium chromate, bichromate and trichromate decomposition were investigated by Fischbeck and Spingler [48] who measured the increase of pressure with time in an evacuated vessel. The activation energy is 40.0, 49.0 and 34.0 kcal/mole, respectively. 

The irreversible decompositions of permanganates and chromates release a proportion of the anionic constituent oxygen and form a non-volatile metal oxide product. The activation energy for the decomposition of KMn04 is similar to values for the decompositions of the rubidiiun and caesium salts, which suggests a common rate controlling step [32], This is probably electron transfer within the anionic sublattice [11], The Oj released is not extensively adsorbed on the solid products and is not expected to participate further in the anion breakdovm step and, hence, kinetic characteristics are found to be insensitive to reaction conditions and magnitudes of reported by different workers are similar. 

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