The preparation and crystal structure I of the 1:1 Adduct of glycine with urea

The 1 : l adduct of the α-amino acid glycine with urea has been prepared and its crystal structure determined by X-ray crystallography and refined to a residual R 0.028 for 776 observed reflections. Crystals are monoclinic, space group P2, with two molecules in a cell of dimensions a 7-364(1), b 4.8703(2), c 8.494(1) A, β 98.555(7)°. The polymeric structure is based on a primary cyclic hydrogen-bonded nine-membered ring involving both the carboxyl oxygen and an amino hydrogen of the zwitterionic glycine molecule with the urea amine hydrogen and oxygen respectively. These repeat down the twofold screw axis by hydrogen bonding, with additional lateral interactions completing the three-dimensional network structure