Synonyms: Cuprate(6-), ((P,P',P'',P'''-(1,2-ethanediylbis((nitrilo-kappaN)bis(methylene)))tetrakis(phosphonato-kappaO))(8-))-, potassium hydrogen (1:5:1), (OC-6-21)-;Pentapotassium cupric ethylenedi(nitrilodi(methylenephosphonate));Cuprate(6-), (((1,2-ethanediylbis((nitrilo-kappaN)bis(methylene)))tetrakis(phosphonato-kappaO))(8-))-, pentapotassium hydrogen, (OC-6-21)-;Pentapotassium hydrogen (((ethylenebis(nitrilobis(methylene)))tetrakis(phosphonato))(8-))cuprate(6-);copper(2+) potassium hydrogen [ethane-1,2-diylbis(nitrilodimethanediyl)]tetrakis(phosphonate) (1:5:1:1)