Phase Transition of a Chiral Lead‐Free Hybrid Antimony(III) Halide Crystal.

Chiral organic–inorganic hybrid lead halides have recently attracted great attention due to their unique chirality and diverse functional properties. However, they suffer from highly toxic lead, while lead‐free chiral hybrid metal halides especially those with phase transitions remain sparse. Here, we report a new lead‐free chiral metal halide crystal [R‐3‐fluoropiperidinium]2SbCl5 ([R‐3‐FPP]2SbCl5), which crystalizes in chiral P212121 space group at 293 K and consists of chiral [3‐FPP]+ cations and one‐dimensional [SbCl5]n2− zigzag chains of corner‐sharing SbCl6 octahedrons. Notably, [R‐3‐FPP]2SbCl5 undergoes an above room temperature phase transition at 313 K, which can be attributed to the order‐disorder transition of both the organic [R‐3‐FPP]+ cation and inorganic [SbCl5]2− anions. In addition, [R‐3‐FPP]2SbCl5 also shows a broad band gap of 3.21 eV. This work promotes the exploration of chiral lead‐free hybrid lead halides with phase transitions. [ABSTRACT FROM AUTHOR]