KBiCl2SO4: The First Bismuth Chloride Sulfate Being Second-Order Nonlinear Optical Active

A pentanary chloride sulfate KBiCl2SO4 (1) is synthesized via a simple solution routine. 1 is crystallized in the chiral orthorhombic P2(1)2(1)2(1) with Z = 4, and its one-dimensional structure features a {[BiCl2(SO4)]-}(infinity) chain along the polar axis. Its second-harmonic generation response is approximately 1.7 times that of KDP, and it can achieve phase matchability under the radiation of 1064 nm laser. Its optical energy gap is measured to be 3.95 eV. The density functional theory calculation results indicate that both [BiCl2O3 square](5-) and [SO4](2-) units serve as functional moieties for its promising nonlinear optical performance.