Constitution of network structures with large. inner spaces with antimonate ions

研究了由锑和铟氧化物构成的网络结构，合成了一个新的化合物LiIn_2SbO_6。我们测量了x射线和中子粉末的衍射数据，并通过Rietveld分析确定了其晶体结构。李氏遗址的结构没有紊乱，空间也没有预想的那么大。另一方面，当使用较大的碱金属（如钾）代替锂时，形成了具有较大隧道的荷兰盐型结构的锑铟氧化物网络。此外，荷兰式的氧化锑网络不仅可以包含铟，还可以包含过渡元素。我们还对具有大空腔的焦绿石结构感兴趣，并研究了ASbWO_6体系（A：碱性元素）。如果以钠为碱性元素，则可以得到具有立方焦绿盐结构和正交结构的新形式的NaSbWO_6。新形态的粉末x射线数据的Rietveld分析表明，该结构与LiSbWO_6的正交结构相似，但具有较正交结构略有变形的新的单斜结构。当锂作为碱性元素时，得到了一种具有类似焦绿石结构的氧化物，其结构与报道的不同。这些实验结果表明，由合成反应构建的氧化锑体系的网络结构并不局限于那些热力学最稳定的网络结构。因此，如果我们能找到合适的合成方法，我们可以用氧化锑体系构建广泛的网络结构。

Investigation of the network structures constructed with antimony and indium oxides led to the synthesis of a new compound LiIn_2SbO_6. We measured the X-ray and neutron powder diffraction data, and determined its crystal structure by Rietveld analysis. The structure had no disorder and the space of the Li site was not so large as expected. On the other hand, when larger alkali metals like potassium were used instead of lithium, antimony-indium oxide networks of the hollandite-type structure with larger tunnels were formed. Furthermore, the antimony-oxide network of the hollandite-type could include not only indium but also transition elements. We were interested also in the pyrochlore structures with large cavities, and investigated ASbWO_6 systems (A: alkaline elements). If sodium was used as the alkaline element, a new form of NaSbWO_6 was formed though the compounds with the cubic pyrochlore structure and an orthorhombic structure had been reported. The Rietveld analysis of the powder X-ray data of the new form showed that the structure was similar to the orthorhombic LiSbWO_6 but had a new monoclinic structure slightly deformed from the orthorhombic structure. When lithium was used as the alkaline element, an oxide with a pyrochlore-like structure was obtained, and the structure was different from the reported one. These experimental results indicated that the network structures with antimony oxide systems constructed by the synthetic reactions were not confined only in those that were thermodynamically most stable. Therefore, if we could find suitable synthetic procedures, we could build a wide range of network structures with antimony oxide systems.