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organic compounds
The structures have been determined of four ammonium phosphoglycolate (PG) salts: ammonium phosphoglycolate(1-), NH4.H2PG (I), triammonium phosphoglycolate(1-) phosphoglycolate(2-), 3NH4.H2PG.HPG (II), diammonium phosphoglycolate(2-), 2NH4.HPG (III) and triammonium phosphoglycolate(3-) monohydrate, 3NH4.PG.H2O (IV) (PG = C2H2O6P3-). The P-O(ester) bond in the doubly ionized phosphate group of IV [1.625 (2) Å] is longer than those in mono-ionized phosphate groups [1.580 (2)-1.600 (1) Å]. There are extensive networks of hydrogen bonds in all four crystals in which every O- and N--bonded H atom is involved.