Two Short-Wave UV Antimony(III) Sulfates Exhibiting Large Birefringence

Abstract

In the present work, we have successfully obtained two new UV antimonybased sulfates, NH 4 Sb(SO 4 ) 2 and Ca 2 Sb 2 O(SO 4 ) 4 , by a conventional hydrothermal method. Interestingly, both compounds share similar structural building blocks, such as SbO 4 seesaws and SO 4 tetrahedra, yet they endow discrepant birefringence values measured at 546 nm with values of 0.150 and 0.114, respectively, owing to the different distortions of the SbO 4 groups with SCALP electrons. Moreover, both compounds display large band gaps (4.32 and 4.43 eV, respectively), so they can be used as shortwavelength UV birefringent materials. Moreover, NH 4 Sb(SO 4 ) 2 is a noncentrosymmetric compound, showing a frequency doubling effect of 0.2 × KDP. Detailed structural analyses and calculations confirm the source of superior optical performance and the reasons for the different birefringence of the two compounds. This work provides ideas for the following discovery of antimony-based optical materials with excellent properties.

Optimization of Functional Building Blocks Generates a Substantial Improvement in Birefringence from Sn2OSO4 to Sn3O2(OH)(HSO4)

“…Studies have demonstrated that the macroscopic optical properties of materials are determined by their functional groups, underscoring the significance of selecting the appropriate functional group. − In recent years, non-π-conjugated tetrahedral anionic groups (e.g., SO 4 , PO 4 , and SeO 4 ) have garnered significant attention due to their wide optical transmission window. − This feature is particularly advantageous for the development of optical crystals suitable for short-wave UV applications, as exemplified by the compounds Li 2.9 Cs 1.1 (SO 4 ) 2 (exp. 5.39 eV), GdSr 3 (PO 4 ) 3 (exp.…”