Thermal Expansion in 3d-Metal Prussian Blue Analogs -- A Survey Study
Abstract
We present a comprehensive study of the structural properties and the thermal expansion behavior of 17 different Prussian Blue Analogs (PBAs) with compositions M^II3[(M')^III(CN)6]2.nH2O and M^II2[Fe^II(CN)6].nH2O, where M^II = Mn, Fe, Co, Ni, Cu and Zn, (M')^III = Co, Fe and n = 5 to 18. Temperature-dependent X-ray diffraction studies were performed in the temperature range between -150^oC (123 K) and room temperature. The vast majority of the studied PBAs were found to crystallize in cubic structures of space groupsFm3 m, F4 3m andPm3 m. The temperature dependence of the lattice parameters was taken to compute an average coefficient of linear thermal expansion in the studied temperature range. Of the 17 compounds, 9 display negative values for the average coefficient of linear thermal expansion, which can be as large as 39.7 x 10-6 K-1 for Co3[Co(CN)6]2.12H2O. All of the M^II3[Co^III(CN)6]2.nH2O compounds show negative thermal expansion behavior, which correlates with the Irving-Williams series for metal complex stability. The thermal expansion behavior for the PBAs of the M^II3[Fe^III(CN)6]2.nH2O family are found to switch between positive (for M = Mn, Co, Ni) and negative (M = Cu, Zn) behavior, depending on the choice of the metal cation (M). On the other hand, all of the M^II2[Fe^II(CN)6].nH2O compounds show positive thermal expansion behavior.
- Publication:
-
APS Four Corners Section Meeting Abstracts
- Pub Date:
- October 2011
- Bibcode:
- 2011APS..4CF.E3003A