(1-Amino-2-carbamoylethylidene)diphosphonic acid dihydrate 63583-19-7 Phosphonic acid, (1,3-diamino-3-oxopropylidene)bis-, dihydrate Phosphonic acid, (1-amino-2-carbamoylethylidene)di-, dihydrate alpha-Amino-beta-carboxamidoethylidene-alpha,alpha-diphosphonic acid dihydrate