A₃Zr₂(PS₄)(P₂S₇)₂ (A = K, Rb, Cs) Synthesized by the Metal Oxide-Boron-Chalcogen Routine: A Series of Zirconium-Based...

Infrared (IR) nonlinear optical (NLO) crystals play important roles in IR laser technologies and devices; however, existing materials fall short of meeting the stringent requirements of the high-power laser market. Consequently, the discovery of novel candidates remains a pressing priority. Here, a series of Zr-based thiophosphate NLO crystals A₃Zr₂(PS₄)(P₂S₇)₂ (A = K (1), Rb (2), Cs (3)) were successfully synthesized via the facile reactive flux assisted metal oxide-boron-chalcogen (RF-MOBQ) method. 1-3 are the first NLO compounds with the coexistence of PS₄ tetrahedra and P₂S₇ dimers, and both act as the NLO functional motifs. 1-3 exhibit phase-matchable second-harmonic generation (SHG) responses of 0.4-0.5 × AgGaS₂. Theoretical calculation results confirm that their SHG responses originate from the synergistic effect between ZrS₇ polyhedra and the two P_xS_y units. This work enriches the structural chemistry of Zr-based thiophosphates and provides a series of promising IR NLO crystals.