“…Due to the abundant structural chemistry and excellent physical properties of ternary silicon phosphides containing transition metals, extensive research has been carried out on their nonlinear optical and thermoelectric properties. [1][2][3][4] A number of representative ternary silicon phosphides have been reported such as NiSi 2 P 3 (Imm2), 5 Si 3 AlP (Cc), 6 RhSi 3 P 3 and IrSi 3 P 3 (C2), 7 PtSi 2 P 2 (P2 1 ), 8 LnSi 2 P 6 (Cmc2 1 , Ln ¼ La, Ce, and Pr), 9 and Ag 2 SiP 2 (I 42d). 10 Among these, the chalcopyrite structure II-IV-V 2 (II-Mg, Zn, Cd; IV-Si, Ge; and V-P, As) crystals, such as CdSiP 2 and ZnGeP 2 , have great important applications in mid-infrared nonlinear optics owing to their outstanding nonlinear optical properties.…”