Sr(NO₃)(NH₂SO₃)·H₂O: First Nitrate Sulfamate Revealing Remarkable Second Harmonic Generation and Optimized Birefringence

The approach of synergistically combining mixed chromophores has garnered significant attention attributed to its ability to leverage the advantages of both groups and design novel nonlinear optical (NLO) materials. Herein, Sr(NO₃)(NH₂SO₃)·H₂O, a noncentrosymmetric compound, which represents the first reported nitrate sulfamate compound, is successfully designed and synthesized. The compound features zigzag [SrNO₁₀(H₂O)]_∞ infinite layers, forming a honeycomb‐like graphene topology in its layered structure. The unique arrangement results in an excellent second harmonic generation response, 5.1 times that of KH₂PO₄, and an optimized birefringence of 0.06650 at 532 nm. In addition, the presence of interlayered covalent [NH₂SO₃] groups facilitates improved crystal growth habits, resulting in a large single crystal measuring 19.0 × 17.0 × 3.5 mm³. In this discovery, a new class of NLO materials is introduced and the scope of structural chemistry is significantly expanded.