EINECS 227-494-2, 1-Naphthalenesulfonic acid,5-hydroxy-6-((2-hydroxy-5-nitrophenyl)azo)-,monosodium salt, Sodium 5-hydroxy-6-((2-hydroxy-5-nitrophenyl)azo)naphthalene-1-sulphonate, 1-Naphthalenesulfonic acid,5-hydroxy-6-(2-(2-hydroxy-5-nitrophenyl)diazenyl)-,sodium salt (1:1),