Also Called: Cobaltate (6-), [[[1,2-ethanediylbis[nitrilobis(methylene)]]tetrakis[phosphonato]](6-)-N,N',O,O'',O'''',O'''''']-,pentaammonium hydrogen, (OC-6-21)-;Cobaltate(6-), [[[1,2-ethanediylbis[nitrilobis(methylene)]]tetrakis[phosphonato]](8-)-N,N',OP,OP',OP'',OP''']-, pentaammonium hydrogen, (OC-6-21)-;Cobaltate(6-), [[P,P',P'',P'''-[1,2-ethanediylbis[(nitrilo-.kappa.N)bis(methylene)]]tetrakis[phosphonato-.kappa.O]](8-)]-, ammonium hydrogen (1:5:1), (OC-6-21)-;Cobalt and cobalt compounds