LiM II (IO 3 ) 3 (M II =Zn and Cd): Two Promising Nonlinear Optical Crystals Derived from a Tunable Structure Model of α‐LiIO 3

Excellent nonlinear optical materials simultaneously meet the requirements of large SHG response, phase‐matching capability, wide transparency windows, considerable energy band‐gap, good thermal stability and structure stability. Herein, two new promising nonlinear optical (NLO) crystals LiM II (IO 3 ) 3 (M II =Zn and Cd) are rationally designed by the aliovalent substitution strategy from the commercialized α‐LiIO 3 with the perfect parallel alignment of IO 3 groups. Compared with parent α‐LiIO 3 and related A I 2 M IV (IO 3 ) 6 , the title compounds exhibit more stable covalent 3D structure, and overcome the racemic twinning problem of A I 2 M IV (IO 3 ) 6 . More importantly, both compounds inherit NLO‐favorable structure merits of α‐LiIO 3 and show larger SHG response (≈14× and ≈12×KDP), shorter absorption edge (294 and 297 nm) with wider energy band‐gap (4.21 and 4.18 eV), good thermal stability (460 and 430 °C), phase‐matching behaviors, wider optical transparency window and good structure stability, achieving an excellent balance of NLO properties.