A single-stage low-temperature hydrothermal synthesis route has been successfully developed for the preparation of pyrite FeS2. The as-prepared pyrite FeS2 was characterized by X-ray diffraction (XRD), a Rietveld refinement method, scanning electron microscopy (SEM) and ultraviolet-visible (UV-VIS) spectrophotometry. The XRD and Rietveld structure refinement indicated that the sample structure is a typical AB(2) cubic of space group Pa3 with a lattice constant a = 5.4151 Angstrom and a Wyckoff parameter u = 0.3868. SEM showed that the polycrystalline pyrite was well crystallized. A possible mechanism for the formation mechanism of the pyrite is discussed. The influences of reaction time and pH on the formation of the target compound were investigated. (C) 2004 Elsevier B.V. All rights reserved.