disodium 8-(phenylamino)-5-[[4-[(6-sulphonato-1-naphthyl)azo]-1-naphthyl]azo]naphthalene-1-sulphonate

8-(Phenylamino)-5-[[4-[(6-sulfo-1-naphthalenyl)azo]-1-naphthalenyl]azo]-1-naphthalenesulfonic acid disodium salt