tetrasodium 5,5'-[carbonylbis[imino-4,1-phenylenecarbonylimino(2-sulphonato-4,1-phenylene)azo]]bis[6-amino-4-hydroxynaphthalene-2-sulphonate]

5,5'-[Carbonylbis[imino-4,1-phenylenecarbonylimino(2-sulfo-4,1-phenylene)azo]]bis(6-amino-4-hydroxy-2-naphthalenesulfonic acid)tetrasodium salt