||Invariant nature of substituted element in metal-hexacyanoferrate
Niwa, Hideharu ,
Kobayashi, Wataru ,
Shibata, Takayuki ,
Nitani, HiroakiMoritomo, Yutaka
7p.13225 , 2017-10 , Nature Publishing Group
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 (Mh) and guest (Mg) transition metals in metal-hexacyanoferrate (M-HCF), Na x (Mh, Mg)[Fe(CN)6] y (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 Mg are essentially the same as those in the pure compound, i.e, Mg-HCF. Such an invariant nature of Mg in M-HCF is in sharp contrast with that in layered oxide, in which the Mg valence changes so that local Mg-O distance (d M-Og) approaches the Mh-O distance (d M-Oh).