NaVSeO5: synergistic combinations to synthesize excellent birefringent materials

Novel NaVSeO5 birefringent crystals were successfully synthesized using a multifunctional group synergistic strategy, which combines a two-dimensional layered structure consisting of stereochemically active lone pairs [SeO3] and anomalous [VO6] polyhedra. Polarization microscopy tests reveal that NaVSeO5 possesses significant birefringence (0.180@546 nm). Theoretical analysis suggests that this birefringence is attributed to the synergistic effect between highly distorted V–O polyhedra and stereochemically active lone pairs of Se4+. Based on UV-Vis-NIR diffuse reflectance analysis, the crystal NaVSeO5 demonstrates a cut-off edge below 336 nm. This study provides valuable insights for future exploration of novel birefringent crystal materials.