disodium 6-[[2,6-dihydroxy-3-[(2-hydroxy-3-nitro-5-sulphonatophenyl)azo]phenyl]azo]-4-hydroxy-3-[(4-nitrophenyl)azo]naphthalene-2-sulphonate

6-[[2,6-Dihydroxy-3-[[2-hydroxy-3-nitro-5-(sodiosulfo)phenyl]azo]phenyl]azo]-4-hydroxy-3-[(4-nitrophenyl)azo]-2-naphthalenesulfonic acid sodium salt