Synonyms: sodium 2-[[4-[(4-hydroxyphenyl)azo]phenyl]amino]-5-nitrobenzenesulphonate;Benzenesulfonic acid, 2-[[4-[(4-hydroxyphenyl)azo] phenyl]amino]-5-nitro-, monosodium salt;2-[[4-[(4-Hydroxyphenyl)azo]phenyl]amino]-5-nitrobenzenesulfonic acid sodium salt;2-[4-(4-Hydroxyphenylazo)anilino]-5-nitrobenzenesulfonic acid sodium salt;2-(4-((p-Hydroxyphenyl)azo)phenylamino)-5-nitrobenzenesulfonic acid, sodium salt;Benzenesulfonic acid, 2-((4-((p-hydroxyphenyl)azo)phenyl)amino)-5-nitro-, sodium salt;Benzenesulfonic acid, 2-((4-(2-(4-hydroxyphenyl)diazenyl)phenyl)amino)-5-nitro-, sodium salt (1:1);Einecs 266-860-6