tetrasodium 7-[(1,8-dihydroxy-3,6-disulphonato-2-naphthyl)azo]naphthalene-1,3-disulphonate

7-[(1,8-Dihydroxy-3,6-disulfo-2-naphtyl)azo]-1,3-naphthalenedisulfonic acid tetrasodium salt

1,3-Naphthalenedisulfonic acid, 7-[(1,8-dihydroxy-3,6-disulfo-2-naphthalenyl)azo]-, tetrasodium salt