Recent Development of SnII, SbIII‐based Birefringent Material: Crystal Chemistry and Investigation of Birefringence

Abstract The combination of Sn II or Sb III with π, non‐π‐conjugated units has produced birefringent crystals with birefringence ranging from 0.005 to 0.468@1064 nm. It is proven that introducing Sn II or Sb III into crystals is a feasible strategy to enlarge the birefringence, which not only promotes the miniaturization of fabricated devices, but also effectively modulates polarized light. Herein, recently discovered Sn II , Sb III ‐based birefringent crystals with birefringence investigated are summarized, including their crystal structure and optical properties, especially birefringence. This review also presents the influence of Sn II , Sb III with stereochemically active lone pair on the optical anisotropy. We hope that this work provides a clear perspective on the crystal chemistry of Sn II , Sb III ‐based optical functional crystals and promotes the development of new birefringent crystals with large optical anisotropy.