disodium 5-[[2,4-dihydroxy-5-[(2-hydroxy-3,5-dinitrophenyl)azo]phenyl]azo]-4-hydroxy-3-[(4-nitrophenyl)azo]naphthalene-2,7-disulphonate

5-[2,4-Dihydroxy-5-(2-hydroxy-3,5-dinitrophenylazo)phenylazo]-4-hydroxy-3-(4-nitrophenylazo)-2,7-naphthalenedisulfonic acid disodium salt

2,7-Naphthalenedisulfonic acid, 5-2,4-dihydroxy-5-(2-hydroxy-3,5-dinitrophenyl)azophenylazo-4-hydroxy-3-(4-nitrophenyl)azo-, disodium salt