1668-00-4 2,7-(Bis(2-arsonophenylazo))-1,8-dihydroxynaphthalene-3,6-disulphonic acid 2,7-Naphthalenedisulfonic acid, 3,6-bis((2-arsonophenyl)azo)-4,5-dihydroxy- AI3-52542 ARSENAZO III EINECS 216-788-6 NSC 91528