The thermal decomposition of ammonium chromate (AC) in dynamic air, CO2 and N2 and in static atmospheres and in the presence of MoO3, V2O5, Fe2O3, CuO, MnO2 and Nd2O3 additives was studied by means of TG, DTA, IR spectroscopy and electrical conductivity measurements. It was found that AC
decomposes in four stages, forming unstable intermediates which produce Cr2O3 as a final product. The presence of the different atmospheres and the oxide additives affected the decompositions of these
intermediates and the oxidation state of the chromium ions. Finally, the mechanisms associated with the different decomposition
stages are discussed.