Crystal structure, IR and Mِssbauer spectroscopy and magnetic properties of KZnFe(PO4)2 related to the zeolite-ABW-like compounds

The new iron phosphate KZnFe(PO4)2 has been synthesized by flux method and solid state reaction, and characterized by X-ray diffraction, IR, Mössbauer spectroscopy and magnetic susceptibility. This compound crystallizes in the monoclinic space group C2/c with the cell parameters: a = 13.514(4) Å, b = 13.273(6) Å, c = 8.742(3) Å and β = 100.07(2)°. It displays strong similarities with the phosphates KCoAl(PO4)2 and NaCoPO4 and features some analogies with the zeolite-ABW structural type. 3D framework is built up by a corner-sharing between MO4 (M = 0.5 Zn + 0.5 Fe) and PO4 tetrahedra. The K+ ions are found within crossing tunnels perpendicular to the (1 0 0), (0 1 0) and (0 0 1) planes, delimited by this framework. A Mössbauer study confirmed the presence of Fe3+ ions in a tetrahedral environment. Magnetic measurements revealed an antiferromagnetic behavior with TN = 8.5 K.