tetrasodium 3,3'-[carbonylbis[imino-m-phenylenecarbonylimino(5-methoxy-2-methyl-p-phenylene)azo]]bis[6-hydroxy-5-sulphonatobenzoate]

3,3'-[Carbonylbis[imino-3,1-phenylenecarbonylimino(5-methoxy-2-methyl-4,1-phenylene)azo]]bis[6-hydroxy-5-sulfobenzoic acid disodium] salt