LiNa2Ca8B12O24F6Cl and Li1.2Na2.8B6O11: A Case of Cation-Induced Birefringence Enhancement via Dimensional Changes of Highly Polymerized [B12O24] Motifs

Borates, due to their structural chemistry diversity and exceptional performance, are premier material systems for investigating UV optical crystals. The B-O anionic groups with high polymerization (B ≥ 6) are much less in the borate-based system, which is worthy of further research. Herein, cations with different radii and proportions are introduced to borate system, and two new highly polymerized borates, LiNa