Vanadate Crystals with an Enhanced Birefringence and a Broadened Transparency Spectrum through Controlled [VO 3 ] ∞ Chain Arrangements and Alkali Metal Cation Introduction.

The vanadate (VO) polyhedron offers a compelling avenue for exploring birefringent materials within the infrared frequency range. Among many potential building blocks, the implementation of [VO 3 ] ∞ chains demonstrated great potential as effective birefringent functional units. In this article, we successfully synthesized the Li 0.8 Na 0.2 CsV 2 O 6 ·H 2 O compound, which exhibits a remarkable birefringence of 0.134 at 546.1 nm, as confirmed by the experiment. Notably, the introduction of alkali metals in this compound led to a significantly shorter cutoff edge at 340 nm. Through a comprehensive investigation, Li 0.8 Na 0.2 CsV 2 O 6 ·H 2 O has the shortest UV cutoff edge among all vanadates, whose birefringences are larger than 0.1, to the best of our best knowledge. This finding underscores the application potential of this novel material as a birefringent crystal.