o-(3,6-Disulfo-2-hydroxy-1-naphthylazo)benzenearsonic acid

4-[(2-arsonophenyl)azo]-3-hydroxy-7-naphthalenedisulfonicacid

4-[(2-Arsonophenyl)azo]-3-hydroxy-2,7-naphthalenedisulfonic acid

4-[(2-arsonophenyl)azo]-3-hydroxynaphthalene-2,7-disulphonic acid