Lin Jian, Liu Qi, Yue Zenghui, Diefenbach Kariem, Cheng Liwei, Lin Yuejian, Wang Jian-Qiang
Shanghai Institute of Applied Physics, Chinese Academy of Sciences, 2019 Jia Luo Road, Shanghai 201800, China.
Dalton Trans. 2019 Apr 9;48(15):4823-4829. doi: 10.1039/c8dt05120h.
Expanding the family of f-element bearing molybdate iodates via hydrothermal reactions has yielded ten new rare-earth molybdate iodates with two distinct phases, Ln(MoO2)(IO3)4(OH) (LnMoIO-1, Ln = Ce and Pr) and Ln(Mo2O7)(IO3)(H2O)2 (LnMoIO-2, Ln = Gd-Yb, and Y), as well as the first thorium molybdate iodate, ThF(MO4)(IO3) (ThFMoIO). All three structures exhibit three dimensional frameworks and are exclusively built from lanthanide/actinide polyhedra bridged by molybdates and iodates. Furthermore, the coordination versatility of molybdates (octahedral, square pyramidal, and tetrahedral geometries) results in a diversity of structures. The effect of the lanthanide contraction on the compositions and structures is clearly observed, showing the increase in hydration from the early to late lanthanide analogues and the decrease in unit cell dimensions and the average Ln-O bonding distances across the same structure type. Single crystal X-ray diffraction studies reveal that LnMoIO-1 (Ln = Ce and Pr) crystalize in a noncentrosymmetric space group P21 and the second-harmonic generation (SHG) measurement shows a response of 5 × KDP for PrMoIO-1. In addition, CeMoIO-1 crystallizes as orange coloured tablets which are semiconducting in nature with a band gap of 2.41 eV.
通过水热反应扩展含f元素的钼酸碘酸盐家族，已得到十种新的稀土钼酸碘酸盐，分为两个不同的相，即Ln(MoO2)(IO3)4(OH)（LnMoIO-1，Ln = Ce和Pr）和Ln(Mo2O7)(IO3)(H2O)2（LnMoIO-2，Ln = Gd - Yb以及Y），还有首例钍钼酸碘酸盐ThF(MO4)(IO3)（ThFMoIO）。所有这三种结构均呈现三维框架，且完全由被钼酸盐和碘酸盐桥连的镧系/锕系多面体构成。此外，钼酸盐的配位多样性（八面体、四方锥和四面体几何构型）导致了结构的多样性。清楚地观察到镧系收缩对组成和结构的影响，表现为从早期到晚期镧系类似物水合作用增加，以及在相同结构类型中晶胞尺寸和平均Ln - O键长减小。单晶X射线衍射研究表明，LnMoIO-1（Ln = Ce和Pr）结晶于非中心对称空间群P21，二次谐波产生（SHG）测量显示PrMoIO-1的响应为5×KDP。此外，CeMoIO-1结晶为橙色片状晶体，本质上是半导体，带隙为2.41 eV。
