Thermal-induced structural distortion and charge transfer of Prussian blue analogues K0.4Co1.3[Fe(CN)6] • nH2O

Abstract

In this paper, the Prussian blue analogues K0.4Co1.3[Fe(CN)6]•nH2O ([KCoFe]) were synthesized using the coprecipitation method at room temperature, 40, 60, 80 and 100 °C. XRD shows that as the preparation temperature increases, [KCoFe] undergoes structural distortion. The room temperature phase and the high temperature phase are both face-centered cubic (Fm-3 m) structures with lattice constants of 10.230 Å and 9.980 Å, respectively. Mössbauer spectrum analysis showed that due to the increase of synthesis temperature, [KCoFe] has undergone charge transfer induced spin transition. Part of paramagnetic structure: FeІІІ (, S = 1/2)–CN–CoІІ (, S = 3/2) was transformed into diamagnetic structure: FeІІ (, S = 0)–CN–CoІІІ (, S = 0). This work provides new ideas for designing new Prussian blue analogues magnetic materials. Keyword: Thermal-induced, Prussian blue analogues, Structural distortion, Charge transfer.