Synthesis, structure, and third-harmonic generation measurements of a mixed alkali metal iodate, KLi2(IO3)3

초록

Pure polycrystalline samples and single crystals of a mixed alkali metal iodate, KLi2(IO3)(3) were synthesized through standard solid state and hydrothermal reactions, respectively, by using Li2CO3, K2CO3, and I2O5 as reagents. Single-crystal X-ray diffraction analysis suggests that KLi2(IO3)(3) exhibits a corrugated layered structure consisting of IO3 distorted trigonal pyramids, LiO4 tetrahedra, and K+ cations. Within the layer, both five-membered rings (5-MRs) and six-membered rings (6-MRs) exist. UV-vis diffuse reflectance spectral data suggest that KLi2(IO3)(3) has a wide optical band gap of ca. 4.25 eV. Infrared spectrum of the title compound clearly confirms the existence of IO3 groups in the backbone. The framework of the iodate is thermally stable to ca. 450 degrees C. Third-harmonic generation measurements using 1500 nm radiation indicate that the third-order nonlinear optical susceptibility of KLi2(IO3)(3) is ca. 3 times that of alpha-SiO2. The laser-induced damage threshold of KLi2(IO3)(3) is comparable to that of alpha-SiO2. Calculated local dipole moment values of IO3 polyhedra are also reported to better understand the asymmetric coordination environment.

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