2,7-Naphthalenedisulfonic acid, 4-((2,4-dihydroxy-5-((2-hydroxy-4,6-dinitrophenyl)azo)phenyl)azo)-5-hydroxy-, disodium salt 2,7-Naphthalenesulfonic acid, 4-((2,4-dihydroxy-5-((2-hydroxy-4,6-dinitrophenyl)azo)phenyl)azo)-5-hydroxy-, disodium salt 63589-12-8