dodecaammonium [ethane-1,2-diylbis[[(phosphonatomethyl)imino]ethane-2,1-diylnitrilobis(methylene)]]tetrakisphosphonate

[1,2-Ethanediylbis[[(phosphonomethyl)imino]-2,1-ethanediylnitrilobis(methylene)]]tetrakisphosphonic acid dodecaammonium salt