Sr(NH₂SO₃)(NO₃)·H₂O: An Ultraviolet Nonlinear Optical Material Exhibiting Strong Second-Harmonic Generation Response...

Second-harmonic generation (SHG) response and birefringence stand as fundamental optical properties for nonlinear optical (NLO) materials. Up to now, engineering a strong SHG response and substantial birefringence in the sulfamate system has proven to be exceedingly challenging. A novel noncentrosymmetric compound, Sr(NH₂SO₃)(NO₃)·H₂O, has been meticulously designed by introducing the (NO₃)^- group characterized by significant polarizability anisotropy and hyperpolarizability into the polar non-π-conjugated (NH₂SO₃)^- system. This compound exhibits a robust SHG response (5.2 × KDP), ample birefringence (0.077 at 546.1 nm), and a short ultraviolet (UV) absorption edge (290 nm). The linear and nonlinear optical properties can be attributed to the (NO₃)^- group and the (NH₂SO₃)^- group. This study presents an effective approach that contributes to the design of more composite anionic UV NLO materials with excellent and balanced optical properties.