A₂Pb₃[H₂N(CH₂COO)₂]₃Cl₅ (A = K, Rb): Porous Crystals Constructed on [Pb₃Cl₅O₆] Clusters with Comprehensive Nonlinear Optical Performance

Abstract Nonlinear optical (NLO) crystals that can extend the frequency range of coherent light have significant applications in laser technology, semiconductor manufacturing, and lithography. Herein, two interesting NLO crystals, A₂Pb₃[H₂N(CH₂COO)₂]₃Cl₅ (A = K, Rb), are rationally obtained. Their porous structures are constructed on [Pb₃Cl₅O₆] clusters that possess large hyperpolarizability and polarizability anisotropy, and are arranged in a parallel manner. Remarkably, A₂Pb₃[H₂N(CH₂COO)₂]₃Cl₅ (A = K, Rb) exhibits comprehensive NLO performance, including strong phase‐matching second‐harmonic generation (SHG) response, the widest bandgap among lead oxychloride NLO crystals, larger laser damage threshold than 127 MW cm⁻², suitable birefringence of 0.11@1064 nm, high thermal stability, non‐deliquescence, as well as facile crystal growth. Theoretical calculations and structural analysis demonstrate that their strong SHG response is predominantly originated from the [Pb₃Cl₅O₆] cluster. This study will provide a unique method for the discovery of new interesting NLO crystals in future.