2,7-Naphthalenedisulfonic acid, 5-2,4-dihydroxy-5-4-(4-nitro-2-sulfophenyl)aminophenylazophenylazo-4-hydroxy-3-4-(4-nitro-2-sulfophenyl)aminophenylazo-, tetrasodium salt

5-[2,4-Dihydroxy-5-[4-[4-nitro-2-(sodiosulfo)phenylamino]phenylazo]phenylazo]-4-hydroxy-3-[4-[4-nitro-2-(sodiosulfo)phenylamino]phenylazo]-2,7-naphthalenedisulfonic acid disodium salt

tetrasodium 5-[[2,4-dihydroxy-5-[[4-[(4-nitro-2-sulphonatophenyl)amino]phenyl]azo]phenyl]azo]-4-hydroxy-3-[[4-[(4-nitro-2-sulphonatophenyl)amino]phenyl]azo]naphthalene-2,7-disulphonate