Synonyms: 1,3-Naphthalenedisulfonicacid, 7-[(1,8-dihydroxy-3,6-disulfo-2-naphthalenyl)azo]-, tetrasodium salt(9CI); 1,3-Naphthalenedisulfonic acid,7-[(1,8-dihydroxy-3,6-disulfo-2-naphthyl)azo]-, tetrasodium salt (8CI);1,8-Dihydroxy-2-(6,8-disulfonaphthyl)-2-azo-3,6-disulfonaphthalene, sodium salt