Sn14O11Br6: a promising birefringent material with a [Sn14O11Br6] layer

Abstract

Tin(II)oxybromide, Sn₁₄O₁₁Br₆ (TOB), was synthesized successfully via the high-temperature solution method in a closed system for the first time. Its structure displays two-dimensional [Sn₁₄O₁₁Br₆] layers constructed from highly distorted [SnO₃]⁴⁻ and [SnO₂Br]³⁻ polyhedra. Besides, TOB possesses good thermal stability and a birefringence larger than 0.248 at 546.1 nm. First-principles calculations reveal that TOB shows giant optical anisotropy of Δn = 0.265 at 546 nm owing to the superior arrangement of highly distorted Sn–O/Br polyhedra.