This polycyclic aromatic dione, also known as o-naphthoquinone, presents as a yellow to deep yellow red crystalline powder. Store in a freezer, under inert gas. This substance is heat sensitive and air sensitive. 1,2-Naphthoquinone is known to be incompatible with oxidizing agents and should not be handled near them. This chemical is harmful if swallowed and causes skin irritation as well as serious eye irritation.