Acid Orange 156 Chemical Name Acid Orange 156 C.I. No. 26501 CAS No. 68555-86-2 Synonyms Weak Acid Orange 3G, Weak Acid Orange ALG, Weak Acid Orange E-GNS, Acid Orange 3G, Acid Orange C-GNS Molecular Formula C21H19N4NaO5S Molecular Weight 462.46