Figure 3
Electron-density samples (in e Å−3 units) calculated on a 0.4 Å grid and sorted in ascending order. Left and right columns correspond to a light-atom structure with composition C160N2O10 and to a heavy-atom structure with composition C48O4P4S4Cl32Nb8 (Irngartinger et al., 1999; Stumpf et al., 1999). Top and bottom rows come from ideal data at and 1.2 Å resolutions. It can be clearly seen that large electron density is concentrated in a small fraction of space – this behaviour is stronger with higher-resolution data and when heavy atoms are present. |