2,7-Naphthalenedisulfonic acid, 3-hydroxy-4-[2-(4-nitrophenyl)diazenyl]-, sodium salt (1:2)
2,7-Naphthalenedisulfonic acid, 3-hydroxy-4-[(p-nitrophenyl)azo]-, disodium salt
2,7-Naphthalenedisulfonic acid, 3-hydroxy-4-[(4-nitrophenyl)azo]-, disodium salt
2-Naphthol-3,6-disulfonic acid, 1-(p-nitrophenylazo)-, disodium salt