disodium 7-[[2,6-dihydroxy-3-[[4-[(4-sulphonatophenyl)azo]phenyl]azo]phenyl]azo]-4-hydroxynaphthalene-2-sulphonate

7-[[2,6-Dihydroxy-3-[[4-[[4-(sodiosulfo)phenyl]azo]phenyl]azo]phenyl]azo]-4-hydroxy-2-naphthalenesulfonic acid sodium salt