SbHPO 3 F: 2D van der Waals Layered Phosphite Exhibiting Large Birefringence.

A novel antimony(III)-based phosphite, SbHPO 3 F, featuring a unique two-dimensional (2D) van der Waals layered structure, has been successfully designed and synthesized via the simultaneous employment of optically active moieties including SbO 3 F seesaw and tetrahedral HPO 3 groups. Its optimized layered arrangement formed by the alternating connection of 4-membered rings (4-MRs) and 8-MRs endows the title compound with desirable optical properties including a large birefringence and short ultraviolet (UV) cutoff edge, implying that it is a potential UV birefringent material.