disodium 8-amino-4-hydroxy-3-[[4-[(4-sulphonatophenyl)azo]phenyl]azo]naphthalene-2-sulphonate

8-Amino-4-hydroxy-3-[[4-[[4-(sodiooxysulfonyl)phenyl]azo]phenyl]azo]-2-naphthalenesulfonic acid sodium salt