Synthesis, spectroscopic, thermal, and structural characterization of complex ferrocyanides KLnFe(II)(CN)6•3.5H2O (Ln = Gd-Ho)

Four new mixed metal cyanides of lanthanides (Ln = Gd-Ho) and iron with the general formula KLnFe(CN)(6) . 3.5H(2)O have been synthesized and characterized by chemical, infrared and thermal techniques. X-ray diffraction (XRD) analysis have shown that all the complexes have orthorhombic unit cells with space group Cmcm. Cyanide bridges link to nine coordinated LnN(6)(H2O)(3) groups to the octahedral FeC6 groups. Cavities within the structure are occupied by uncoordinated zeolitic water molecules and potassium ions. The potassium cations form a pseudo-hexagonal 2D sublattice. Thermal decomposition involves two consecutive steps: dehydration and inorganic residue evolution to ternary oxides.