When Aluminium nitrate is heated , i got yellow amorphous solid which did not not melt on further heating. What compound is that?Aluminium nitrate follows the rules for metal nitrate decomposition. Group I nitrate Na K etc --- nitrite + oxygen Other metal nitrate --- Metal Oxide + nitrogen dioxide + oxygen So your final product is aluminium oxide.l would say you have mostly aluminum oxide as a product which probably contains some Nitrogen dioxide gas, a second product of the decomposition of aluminum nitrate. If I were you I would not heat nitrate salts as they can explode upon heating. they also need to be kept away from any kind of reducing agent such as powdered metals, or any fuels, reactions can be violent.Other related question