Abstract

In this study, we successfully synthesized two novel non-centrosymmetric (NCS) antimony halide compounds, RbSbF3Cl and Rb3Sb4F14Cl. These compounds were formed by combining Sb3+ cations, which possess stereochemically active lone pairs (SCALP), with halogen atoms (fluorine and chlorine). The introduction of mixed halogen atoms enables Sb atoms to adopt multiple coordination modes, which in turn promotes the development of both compounds towards NCS structures. Notably, Rb3Sb4F14Cl demonstrated a large second harmonic generation (SHG) response, approximately three times greater than that of KH2PO4 (KDP), along with a wide transparency range from 0.27 to 13.3 μm and a high laser damage threshold (LDT) of 223 MW/cm2. These exceptional properties indicate that Rb3Sb4F14Cl is a highly promising nonlinear optical (NLO) crystal with excellent overall performance, making it suitable for potential applications spanning the short-wave ultraviolet (UV) to mid-infrared (IR) spectral regions. In contrast, RbSbF3Cl exhibits a large birefringence of 0.31 at 546 nm as a uniaxial crystal, suggesting its practicability as a birefringent material.