Iron-chromium cyanide molecular magnet nanoparticles have been synthesized by using poly(vinylpyrrolidone) as a matrix. The results of field emission scanning electron microscope indicate that the nanoparticles are uniform and dispersed. The diameters of the nanoparticles can be controlled by the PVP/Fe2+ feed ratio. X-ray diffraction measurement results show that the iron-chromium cyanide nanoparticles are crystalline with a face-centered-cubic structure. The peaks on infrared spectrum in the region from 2000 to 2200 cm(-1) come from the stretching of CN ligands in the nanoparticles. The magnetic properties of the nanoparticles were also discussed. (c) 2007 Elsevier B.V. All rights reserved.