Song Jie, Kong Xianghao, Li Conggang, Jiao Jinmiao, She Yuheng, Ye Ning, Hu Zhanggui, Wu Yicheng
Tianjin Key Laboratory of Functional Crystal Materials, Institute of Functional Crystal, Tianjin University of Technology, Tianjin 300384, China.
State Key Laboratory of Crystal Materials and Institute of Crystal Materials, Shandong University, Jinan 250100, China.
Inorg Chem. 2024 Aug 5;63(31):14786-14793. doi: 10.1021/acs.inorgchem.4c02759. Epub 2024 Jul 26.
Borates, as advanced optical materials, have garnered wide interest due to their diverse structural configurations and great potential for applications in the ultraviolet (UV) regions. Herein, we synthesized a new rare-earth borate crystal, namely, KNaYBO, which is classified as one of the ABReBO compounds, where A and B represent alkali metal and Re denotes rare-earth metal. KNaYBO adopts in the monoclinic space group 2/ (No. 14), showcasing a three-dimensional (3D) framework composed of a planar triangular configuration of [BO] units and distortive [YO] polyhedra. Notably, both dihedral angles between distinct [BO] units reach 79.6°, which represents an unprecedented structural feature in monoclinic ABReBO-type crystals. Moreover, the compound has a short UV absorption edge at around 204 nm, corresponding to a wide band gap of approximately 5.67 eV. Additionally, it possesses a moderate birefringence of 0.028 at 1064 nm. Further analysis utilizing theoretical calculations suggests that the optical behaviors of KNaYBO are mainly governed by its basic structural unit [BO] triangles and distorted [YO] polyhedra. These findings enrich the structure chemistry of rare-earth borates and offer valuable insights for the design of optical crystals in the UV wavelength range.
硼酸盐作为先进的光学材料，因其多样的结构构型以及在紫外（UV）区域的巨大应用潜力而备受关注。在此，我们合成了一种新型稀土硼酸盐晶体，即KNaYBO，它属于ABReBO化合物之一，其中A代表碱金属，B代表稀土金属。KNaYBO属于单斜空间群2/（编号14），呈现出由[BO]单元的平面三角形构型和畸变的[YO]多面体组成的三维（3D）框架。值得注意的是，不同[BO]单元之间的二面角均达到79.6°，这在单斜ABReBO型晶体中代表了一种前所未有的结构特征。此外，该化合物在约204 nm处有一个短的紫外吸收边，对应于约5.67 eV的宽带隙。此外，它在1064 nm处具有0.028的适度双折射。利用理论计算的进一步分析表明，KNaYBO的光学行为主要由其基本结构单元[BO]三角形和畸变的[YO]多面体决定。这些发现丰富了稀土硼酸盐的结构化学，并为紫外波长范围内光学晶体的设计提供了有价值的见解。
