3,3'-Benzidinedisulfonic acid

4,4'-diamino-3,3'-biphenyldisulfonic acid; 4,4'-Diamino-(1,1'-biphenyl)-3,3'-disulfonic acid; Benzidine-3,3''-disulfonic acid; 2-amino-5-(4-amino-3-sulfophenyl)benzenesulfonic acid; 2-amino-5-(4-amino-3-sulfo-phenyl)benzenesulfonic acid; 2-azanyl-5-(4-azanyl-3-sulfo-phenyl)benzenesulfonic acid; [1,1'-Biphenyl]-3,3'-disulfonicacid, 4,4'-diaMino-;4,4'-diamino-3,3'-biphenyldisulfonic acid