2,7-Naphthalenedisulfonic acid, 4-amino-6-5-4-8-amino-1-hydroxy-3,6-disulfo-7-4-2-(sulfooxy)ethylsulfonylphenylazo-2-naphthalenylazobenzoylamino-2-sulfophenylazo-5-hydroxy-3-4-2-(sulfooxy)ethylsulfonylphenylazo-, sodium salt

4-[4-amino-5-hydroxy-3-(4-(2-sulfoxyethylsulfonyl)phenylazo)-2,7-disulfonapht-6-ylazo]-6-[3-(4-amino-5-hydroxy-3-(4-(2-sulfoxyethylsulfonyl)phenylazo)-2,7-disulfonapht-6-ylazo]phenylcarbonylamino]benzenesulfonic acid, sodium salt