[C(NH2)3]2[C2H5(C2O4)]Cl: rational design of a metal-free UV birefringent crystal through the synergistic assembly of three distinct motifs

Abstract

Developing metal-free birefringent crystals is of great significance in laser technology. Herein, a metal-free birefringent crystal, [C(NH₂)₃]₂[C₂H₅(C₂O₄)]Cl, was rationally obtained via a hydrogen-bond-directed assembly of three distinct motifs. It exhibits a wide band gap (3.987 eV) and significant birefringence (0.120@546 nm), demonstrating the strategy's efficacy for metal-free UV birefringent materials.