Fig. 1. Schematic illustration of the structure of ZnAtzPO₄.

(A) Three-dimensional structure of ZnAtzPO₄ viewed from a. (B) Connolly surface indicating periodically expanded and contracted cross-section area of ZnAtzPO₄. (C) Schematic representation of the pocket-like space containing two symmetric passages. (D) Local environment and aperture size of the narrow bottleneck structure. [Color mode: C, gray (40%); H, gray (25%); N, light blue; Zn, sky blue; P, yellow; O, red. Bidentate-coordinated Atz ligands are highlighted by rose.]