Crystal structures and theoretical studies of polyphosphate LiZnP3O9 for nonlinear optical applications
Zhiqing Xie, Xin Su, Hanqin Ding, Hongyi Li
文献索引：10.1016/j.jssc.2018.03.032
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摘要
Nonlinear optical materials have attracted worldwide attention owing to their wide range of applications, specially in the laser field. Phosphates with noncentrosymmetric structures are potential candidates for novel ultraviolet (UV)-NLO materials, because they usually display short UV cut-off edges. In this work, a polyphosphate, the LiZnP3O9 polyphosphate crystals were grown through spontaneous crystallization from high-temperature melts. It crystallizes in the orthorhombic space group P212121 with unit cell parameters a = 8.330(3) Å, b = 8.520(3) Å, c = 8.635(3) Å, and Z = 4. In the structure, all the P atoms are coordinated by four oxygen atoms forming the [PO4] tetrahedra and further connected to generate a zig-zag [PO3]∞ anionic framework. Thermal analysis, IR spectroscopy, UV–vis–NIR diffuse reflectance spectrum and powder second harmonic generation measurements are performed. In addition, the first-principles calculation was employed for better understanding the structure–property relationships of LiZnP3O9.