Mellitic anhydride

Other names: Benzo[1,2-c:3,4-c′:5,6-c′′]trifuran-1,3,4,6,7,9-hexone

C₁₂O₉

29/50 common

Mellitic anhydride is a fascinating carbon-oxygen compound with a symmetrical structure consisting of a benzene core where each carbon atom is fused to an anhydride group. This molecule represents one of the most oxygen-rich stable aromatic compounds. It appears as colorless to pale yellow crystals that are highly sensitive to moisture, readily hydrolyzing to mellitic acid (benzenehexacarboxylic acid). Historically significant, mellitic acid forms the beautiful mineral mellite (aluminum benzenehexacarboxylate hexadecahydrate), a honey-yellow gemstone sometimes called "honeystone" that was first discovered in lignite deposits. The anhydride's exceptional electron-deficient character makes it a powerful electron acceptor in charge-transfer complexes. Mellitic anhydride serves as a precursor in the synthesis of various carbon-rich materials and has been studied for applications in supramolecular chemistry. Its unusual structure, with six carbonyl groups radiating from a central benzene ring, makes it an intriguing target for theoretical studies on aromaticity and electronic delocalization.