Also Called: Cobaltate(8-), bis[4-hydroxy-3-[(2-hydroxy-5-nitrophenyl)azo]-7-[(3-phosphonophenyl)amino]-2-naphthalenesulfonato(5-)]-, tetraammonium tetrahydrogen;Cobaltate(8-), bis[4-(hydroxy-.kappa.O)-3-[2-[2-(hydroxy-.kappa.O)-5-nitrophenyl]diazenyl-.kappa.N1]-7-[(3-phosphonophenyl)amino]-2-naphthalenesulfonato(5-)]-, ammonium hydrogen (1:4:4);Cobalt and cobalt compounds