The products obtained during the thermal decomposition of ammonium meta-vanadate depend on the configuration of the container, the mass of the sample, the heating rate and the composition of the carrier gas. The decomposition in an uncapped container produced (NH 4 ) 2 V 4 O 11 , NH 4 V 3 O 8 , and V 2 O 5 as the apparent stable products while the products in a capped container were NH 4 V 3 O 8 , and V 2 O x where x was between 4 and 5. These differences are attributed to the different amounts of the evolved gases in the cell. EGA-FTIR clearly established that the reduced final product in the capped cell resulted from a reaction between NH 3 and the V 2 O 5 formed during the decomposition. A pre-equilibrium kinetics model where the rate of the reverse reaction depends on the partial pressure of the gaseous products in the cell could explain the different reaction intermediates. This model provides a possible explanation for the different apparent activation energies that have been reported for the thermal decomposition of other compounds where a reversible step could occur in the decomposition mechanism.
KeywordsAmmonium Meta-VanadateThermal DecompositionKineticsActivation Energy
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