Solid state decomposition studies on fluoroperoxo species of transition metals. Part XI. Kinetics of isothermal and photochemical decomposition of K₂TaO₂F₅.H₂O

Abstract

The kinetics of the solid state isothermal and photochemical decompositions of K2TaO2F5.H2O have been studied by measuring the pressure of oxygen evolved in a constant volume apparatus. Isothermal decomposition of the sample was carried out in the temperature range 528 to 553 K. The reaction is predominantly deceleratory. The initial stage of the decomposition can be described by the unimolecular decay law whereas the later stage obeys the contracting volume equation. The activation energy values of the two processes are 120 and 90 kj mol−1, respectively. The photolysis of the compound at different intensities yields a pressure–time curve which can be described by the rate equations p = kt1/2. The rate of photolysis was found to be linearly dependent on intensity, indicating a monoexcitation process for peroxide decomposition.