Crystal structure, thermal expansion, and water occupancies in Prussian Blue Analogs: A combined neutron, x-ray, and microscopy study

Prussian Blue Analogs are a family of compounds based on the structure of Prussian Blue, FIII4[FeII(CN) 6]3. The Prussian Blue Analogs used in this study are of the form MII3[M'III(CN)6] 2 • xH2O, where x typically is between 10 and 20 (but close to zero for dehydrated samples) and M and M' are transition metals. Prussian Blue Analogs crystallize mostly in cubic framework structures with one of the metal ions surrounded octahedrally by carbon and the other by nitrogen. Some Prussian Blue Analogs have extra transition metals in between the octahedra and systematic transition metal vacancies. It is known that Prussian Blue Analogs have two water positions in the lattice structure. The lattice waters are in the systematic vacancies of transition metals in the cubic structure, whereas the interstitial waters are at random positions in the structure. My dissertation tries to accomplish the three objectives listed next. The first is to give a historical background on Prussian Blue and its Analogs. The second is to provide electron microscopy analysis of structure, shape and morphology of Prussian Blue Analogs produced via chemical precipitation methods. Finally, my dissertation will use X-ray and neutron diffraction analysis to explore the some of the structural properties of Prussian Blue Analogs, including atomic positions and thermal expansion, and its potential relationship to other properties, such as thermal expansion and magnetic properties.