1-Naphthalenesulfonic acid, 3-hydroxy-4-[(2-hydroxy-1-naphthalenyl)azo]-, zinc salt (2:1) 3-Hydroxy-4-[(2-hydroxy-1-naphthalenyl)azo]-1-naphthalenesulfonic acid, monozinc salt 5410-93-5 NSC4203