Figure 5.
Model of the trilayer packing arrangement of stigmasterol hydrate on a water surface, based on an analysis of GIXD measurements thereof12,37 (Figure S14), on the sigmasterol·H2O crystal structure31 (Figure S13B,C), and on the model structure of cholestanol dihydrate (Figures 4D and S12). The trilayer structure viewed along the a-axis incorporates an ordered layer of water molecules whose ice-like hydration structure is probably a double bilayer similar to cholestanol dihydrate. Both structures embody the 10 × 7.5 Å2 monoclinic 21 motif.