新型稀土碘酸盐K_(2)Y(IO_(3))_(5)的合成、结构及光学性质

Synthesis,Structure and Optical Properties of Novel Rare Earth Iodate K_(2)Y(IO_(3))_(5)

本文采用水热法合成了一例新的稀土碘酸盐K_(2)Y(IO_(3))_(5),通过单晶X射线衍射对其结构进行了解析。结果表明:K_(2)Y(IO_(3))_(5)属三斜晶系,P1空间群,晶胞参数a=10.069(6)A,b=8.418(1)A,c=11.754(2)A,α=109.664(5)°,β=90.518(6)°,γ=91.565(5)°,Z=2;其晶体结构是由K—O多面体连接零维[Y_(2)(IO_(3))_(10)]^(4-)阴离子基团构成。采用紫外-可见-近红外漫反射光谱研究其透光范围,表明K_(2)Y(IO_(3))_(5)透光范围为0.25~12.46μm。采用TG-DSC分析了其热稳定性质,热分解温度为365℃。此外,采用第一性原理计算了K_(2)Y(IO_(3))_(5)的能带结构,结果表明I-5p、O-2p轨道主导了结构的光学性质。

A new rare earth iodate K_(2)Y(IO_(3))_(5) has been synthesized by hydrothermal method in this paper.Its structure was determined by single crystal diffraction.The results show that K_(2)Y(IO_(3))_(5) crystallizes in triclinic crystal system with P1 space group.Its crystal cell parameters are a=10.069(6)A,b=8.418(1)A,c=11.754(2)A,α=109.664(5)°,β=90.518(6)°,γ=91.565(5)°,Z=2.The structure of K_(2)Y(IO_(3))_(5) features a zero-dimensional[Y_(2)(IO_(3))_(10)]^(4-)anion group,which further linked by K—O polyhedrons to construct the whole framework.In addition,UV-Vis-NIR diffuse reflection spectroscopy shows that K_(2)Y(IO_(3))_(5) has a wide transmission range about 0.25~12.46μm.TG-DSC indicated that the thermal decomposition temperature of K_(2)Y(IO_(3))_(5) is 365℃.Meanwhile,the band structure of K_(2)Y(IO_(3))_(5) is also calculated using first principles.The results shows that the I-5p and O-2p orbits dominate the optical properties of the structure.