NH4Sb2(C2O4)F5: A novel UV nonlinear optical material synthesized in deep eutectic solvents

The deep eutectic solvents was first employed to solve the hydrolysis of Sb3+ cations in Sb(III)-oxyacid system to explore new nonlinear optical materials, producing a novel antimony(III) fluoride oxalate named NH4Sb2(C2O4)F5. The title compound featured a 3D noncentrosymmetric structure composed of [Sb2(C2O4)F5]- anionic clusters and NH4+ cations. The cooperative effect of the planar π-conjugated [C2O4]2- anionic groups and the Sb3+ cations with stereochemically active lone pairs induce a relatively strong SHG response (1.1×KH2PO4) and a large birefringence ([email protected] nm), which was confirmed by detailed theoretical calculations. The overall performances indicate that NH4Sb2(C2O4)F5 is a potential ultraviolet nonlinear optical material. The successful application of deep eutectic solvents in the synthesis for easy hydrolytic materials system opens the door to exploring new inorganic solid functional materials.