Optimization of Functional Building Blocks Generates a Substantial Improvement in Birefringence from SnOSO to SnO(OH)(HSO).

In this work, two tin(II)-based sulfates, SnOSO and SnO(OH)(HSO), were synthesized via the mild hydrothermal method. Both compounds employ the Sn cation with stereochemically active lone pair (SCALP) electrons and non-π-conjugated tetrahedral anionic groups SO as the functional structural blocks. Interestingly, the experimental birefringence of SnO(OH)(HSO) is 0.

NaSn(CO)F and NaSnCOF·HO: two tin(II) fluoride oxalates display large birefringence.

Birefringent materials play an important role in laser techniques as an essential part of optical devices. Therefore, the exploration of high-performance birefringent materials has been a central focus of researchers. Herein, two tin(II) fluoride oxalates NaSn(CO)F and NaSnCOF·HO were gained by the combination of birefringence-active groups of Sn with stereochemically active lone pairs and planar π-conjugated [CO] groups.