2,7-Naphthalenedisulfonic acid, 4-((2,4-dimethylphenyl)azo)-3-hydroxy-, barium salt (1:1) 68928-54-1 7481-49-4 Barium 4-((2,4-dimethylphenyl)azo)-3-hydroxynaphthalene-2,7-disulphonate EINECS 273-022-3