disodium 4-amino-3,6-bis[[4-[(2,4-dihydroxyphenyl)azo]phenyl]azo]-5-hydroxynaphthalene-2,7-disulphonate

4-Amino-3,6-bis[[4-[(2,4-dihydroxyphenyl)azo]phenyl]azo]-5-hydroxy-2,7-naphthalenedisulfonic acid disodium salt