2'-Amino-4',8-dihydroxy-3,6-disulpho-5'-(2-hydroxy-3,5-dinitrophenylazo)-3'-(4-nitrophenylazo)-1-naphthaleneazobenzene, ferric complex 70693-22-0 Iron, 4-((2-amino-4-hydroxy-5-((2-hydroxy-3,5-dinitrophenyl)azo)-3-((4-nitrophenyl)azo)phenyl)azo)-5-hydroxy-2,7-naphthalenedisulfonate complexes