On heating ammonium dichromate, the products obtained are

The reaction is ${\left({\mathrm{NH}}_4\right)}_2{\mathrm{Cr}}_2{\mathrm{O}}_7\to {\mathrm{N}}_2+4{\mathrm{H}}_2\mathrm{O}+{\mathrm{Cr}}_2{\mathrm{O}}_3$. Ammonium dichromate decomposes on heating to produce nitrogen gas water vapour (gaseous due to the temperature of the reaction), with an orange spark and solid chromium(III) oxide which is green colour. Nitrogen gas is released in this reaction.