Hydrogen Bonding Engineering Achieved Hybrid Antiperovskite Ferroelastic in ( C ₃ H ₈ ON ) ₃ ( SnCl ₆ )Cl

Comprehensive Summary Hybrid antiperovskites have attracted tremendous research interest with unique assembly architecture, holding great promise in ferroelectricity, nonlinear optics, optoelectronic detection, etc . However, constructing hybrid antiperovskite has always been a great challenge, and the ferroelasticity within this family remains unexplored. Here, we report the first case of hybrid antiperovskite ferroelastic, (C 3 H 8 ON) 3 (SnCl 6 )Cl, designed via molecular modification. Through hydrogen‐bond engineering by substituting (C 3 H 6 ON) + cations with (C 3 H 8 ON) + , the stacking arrangement of components in lattice was reconfigured to transform a zero‐dimensional precursor of (C 3 H 6 ON) 2 SnCl 6 into a three‐dimensional hybrid antiperovskite architecture. This structural reorganization successfully induces a ferroelastic phase transition with an Aizu notation of 2 m F222. This work not only enriches the hybrid antiperovskite family, but also sheds new light for designing ferroic materials.