Oxygen rich compounds like chlorate perchlorate K2Cr2O7 etc., when heated gives oxygen but ammonium dichromate gives nitrogen gas when heated. 2KClO3⟶Δ2KCl+3O2↑2Zn(ClO3)2⟶ΔZnCl2+3O24 K2Cr2O7⟶Δ4 K2CrO4+2Cr2O3+3O2↑(NH4)2Cr2O7⟶ΔN2↑+Cr2O3+4H2O