Synonyms: hexasodium 2,2'-[azoxybis[(2-sulphonato-4,1-phenylene)vinylene(3-sulphonato-4,1-phenylene)]]bis[-2H-naphtho[1,2-d]triazole-5-sulphonate];2H-Naphtho[1,2-d]triazole-5-sulfonic acid, 2,2'-[azoxybis[(2-sulfo-4, 1-phenylene)-2,1-ethenediyl(3-sulfo-4,1-phenylene )]]bis-, hexasodium salt;2,2'-[ONN-Azoxybis[[2-(sodiooxysulfonyl)-4,1-phenylene]-2,1-ethenediyl[3-(sodiooxysulfonyl)-4,1-phenylene]]]bis[2H-naphtho[1,2-d]triazole-5-sulfonic acid sodium] salt