disodium 5-[[4-[5-[(7-amino-1-hydroxy-3-sulphonato-2-naphthyl)azo]-1H-benzimidazole-2-yl]phenyl]azo]salicylate

5-[[4-[5-[(7-Amino-1-hydroxy-3-sodiosulfo-2-naphtyl)azo]-1H-benzimidazol-2-yl]phenyl]azo]-2-hydroxybenzenesulfonic acid sodium salt