Crystal and molecular structure of the pyroelectric phase of TGS at 150 K

Abstract

Abstract Single crystals of triglycine sulphate in the pyroelectric phase were crystallised from an aqueous solution of glycine and sulphamic acid. The crystals are monoclinic with the cell dimensions a = 5.6922(9) Å, b = 12.610(3) Å, c = 9.164(2) Å, β = 105.33(1)°, space group P21 and Z = 2. Least-squares refinement using 2870 X-ray (MoKα) reflections (collected at 150 K) has led to an R-factor of 0.025 giving e.s.d. in bond lengths and angles of 0.002 Å and 0.2°, respectively. Two of the three glycine molecules are protonated and the third exists in the zwitterionic state. The hydrogen bonding scheme includes two bifurcated bonds. The shortest O – H … O hydrogen bond has a length of 2.481(2) Å.