4-[[2,6-dihydroxy-3-[(4-nitrophenyl)azo]-5-[(7-sulpho-1-naphthyl)azo]phenyl]azo]naphthalene-1-sulphonic acid, sodium salt

4-[[2,6-Dihydroxy-3-[(4-nitrophenyl)azo]-5-[(7-sulfo-1-naphthalenyl)azo]phenyl]azo]-1-naphthalenesulfonic acid/sodium,(1:x) salt