Evidence for the Existence of Oxygen Clustering and Understanding of Structural Disorder in Prussian Blue Analogues Molecular Magnet M1.5[Cr(CN)6]·zH2O (M = Fe and Co): Reverse Monte Carlo Simulation and Neutron Diffraction Study

A detailed structural disorder investigation of Prussian blue analogues M1.5[Cr(CN)6]·zH2O (M = Fe and Co) has been done by carrying out a reverse Monte Carlo (RMC) simulation on the powder neutron diffraction data. X-ray diffraction, infrared spectroscopy, Mossbauer spectroscopy, and dc magnetization measurements have also been employed to investigate the structural and magnetic properties of the compounds. The Rietveld refinement of the X-ray and neutron diffraction patterns reveals that both compounds are in a single phase with a face-centered cubic crystal structure (space group Fm3m). The observation of characteristic absorption bands in the range 1900–2200 cm–1 of infrared (IR) spectra, which corresponds to the CN stretching frequency of MII—N≡C—CrIII sequence, confirms the formation of Prussian blue analogues, M1.5[Cr(CN)6]·zH2O. The IR study also infers the presence of cyanide flipping in the Fe1.5[Cr(CN)6]·zH2O compound. The Mossbauer study on the Fe1.5[Cr(CN)6]·zH2O compound confirms the presenc...