Figure 3
Ball-and-stick/wire model showing interactions between layers of GLYGLY molecules as viewed (a) perpendicular to the (10) plane. Molecules in the upper and lower layers are coloured red and blue, respectively. R23(6) ring motifs between layers of GLYGLY molecules are shown. Black and orange dotted lines represent NH⋯O and CH⋯O hydrogen bonds, respectively, while pink dotted lines represent weak C=O⋯C=O interactions. Space-filling plots of R23(6) ring motifs at (b) ambient pressure and (c) 4.7 GPa are shown, drawn at the same scale and direction with only the ammonium and carboxyl groups involved in the formation of the rings shown. The colour scheme is the same as that in Fig. 2. |