Synonyms: Cobaltate(3-),bis[6-(amino-kN)-5-[[2-(hydroxy-kO)-3,5-dinitrophenyl]azo-kN1]-1-naphthalenesulfonato(3-)]-,sodium dihydrogen (9CI); Cobaltate(3-),bis[6-amino-5-[(2-hydroxy-3,5-dinitrophenyl)azo]-1-naphthalenesulfonato(3-)]-,sodium dihydrogen; 1-Naphthalenesulfonic acid,6-amino-5-[(2-hydroxy-3,5-dinitrophenyl)azo]-, cobalt complex