Single crystals of a new iron monophosphate K3Fe(PO4)(2) were synthesized by the flux method and characterized by X-ray diffraction, magnetic susceptibility and Mossbauer spectroscopy. The compound crystallizes in the monoclinic system with the space group P2(1)/n and the parameters a=9.598(3)angstrom, b=11.086(2)angstrom, c=15.462(3)angstrom, beta=90.30(2)degrees and Z=8. The crystal structure can be described in terms of [Fe2P4O17](infinity) chains of FeO6 octahedra and PO4 tetrahedra sharing corners and edges. Adjacent chains are linked through common corners to form a three-dimensional framework containing crossing tunnels where the K' ions are located. The magnetic measurements showed the compound to be antiferromagnetic with T-N approximate to 9 K The Mossbauer spectroscopy confirmed the occurrence of octahedral Fe3+ ions in a high spin state. (C) 2008 Elsevier B.V. All rights reserved.