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

Abstract

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.