Sr(NH 2 SO 3 )(NO 3 )·H 2 O: An Ultraviolet Nonlinear Optical Material Exhibiting Strong Second-Harmonic Generation Response and Sufficient Birefringence.

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(NH 2 SO 3 )(NO 3 )·H 2 O, has been meticulously designed by introducing the (NO 3 ) - group characterized by significant polarizability anisotropy and hyperpolarizability into the polar non-π-conjugated (NH 2 SO 3 ) - 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 (NO 3 ) - group and the (NH 2 SO 3 ) - 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.