Figure 5.

Calculated electron localization functions (ELFs) for a) R $\overline{3}$ m, b) Fd $\overline{3}$ m, c) I $\overline{4}$2d, and d) Cc structures with isosurface value 0.55, 0.9, 0.9, and 0.9, respectively. The ELF maps around anionic electrons accompanied with the coordination environment of anionic electrons (Ae) are showed in the bottom. The distribution of anionic electrons reveals a transition from 2D layer (R $\overline{3}$ m), 1D chain (Fd $\overline{3}$ m), and 0D spheres (I $\overline{4}$2d and Cc).