Niwa Hideharu, Kobayashi Wataru, Shibata Takayuki, Nitani Hiroaki, Moritomo Yutaka
Faculty of Pure and Applied Science, University of Tsukuba, Tsukuba, 305-8571, Japan.
Tsukuba Research Center for Interdisciplinary Materials Sciences (TIMS), University of Tsukuba, Tsukuba, 305-8571, Japan.
Sci Rep. 2017 Oct 16;7(1):13225. doi: 10.1038/s41598-017-13719-z.
The chemical substitution of a transition metal (M) is an effective method to improve the functionality of materials. In order to design the highly functional materials, we first have to know the local structure and electronic state around the substituted element. Here, we systematically investigated the local structure and electronic state of the host (M ) and guest (M ) transition metals in metal-hexacyanoferrate (M-HCF), Na (M , M )[Fe(CN)] (1.40 < x < 1.60 and 0.85 < y < 0.90), by means of extended X-ray absorption fine structure (EXAFS) and X-ray absorption near-edge structure (XANES) analyses. The EXAFS and XANES analyses revealed that the local structure and electronic state around M are essentially the same as those in the pure compound, i.e, M -HCF. Such an invariant nature of M in M-HCF is in sharp contrast with that in layered oxide, in which the M valence changes so that local M -O distance (d ) approaches the M -O distance (d ).
过渡金属（M）的化学取代是改善材料功能的有效方法。为了设计高功能材料，我们首先必须了解取代元素周围的局部结构和电子态。在此，我们通过扩展X射线吸收精细结构（EXAFS）和X射线吸收近边结构（XANES）分析，系统地研究了金属六氰合铁酸盐（M-HCF），即Na （M ，M ）[Fe(CN)] （1.40＜x＜1.60且0.85＜y＜0.90）中主体（M ）和客体（M ）过渡金属的局部结构和电子态。EXAFS和XANES分析表明，M 周围的局部结构和电子态与纯化合物（即M -HCF）中的基本相同。M-HCF中M 的这种不变性质与层状氧化物中的情况形成鲜明对比，在层状氧化物中，M 的价态发生变化，使得局部M -O距离（d ）接近M -O距离（d ）。
