Nanocrystalline Prussian Blue analogue Ni-2[Fe(CN)(6)]center dot xH(2)O was synthesized through hydrothermal process at 180 degrees C for 24 h with NiSO4 center dot 6H(2)O and K-4[Fe(CN)(6)]center dot 3H(2)O as precursors. The effects of reactant concentration and protective matrix (Polyethylene glycol 400, PEG-400) on the size and morphology of nanoparticles were investigated. The as-synthesized products were identified as face-centered cubic structure by powder X-ray diffraction. Field-emission scanning electron microscopy and transmission electron microscopy images showed that well dispersed nanoparticles with fairly narrow size distribution were successfully prepared. (c) 2007 Elsevier Ltd. All rights reserved.