Dual-tuning birefringence in hybrid crystals via Cd/Zn metal center and organic ligand isomerism.

This study compares three hybrid crystals. (C9H7NBr)CdCl3·H2O exhibits the highest birefringence (0.405@550 nm) due to distorted polyhedra and parallel organic alignment. Organic ligand branch isomerism maintains birefringence via denser packing, whereas Zn2+ substitution reduces it by canceling polarization vectors, providing a strategy for the fabrication of superior hybrid optical crystals.