Pure ZrO2 nanopowders have been synthesized via sonochemical method, which is a simple and energy efficient way to synthesize inorganic materials. The as-synthesized samples (hydrous zirconia, ZrO2.nH(2)O) are characterized by several techniques: X-ray diffraction (XRD), thermogravimetric analysis (TGA), photoluminescence spectrometer (PLS) and Raman spectrometer (RS). It is shown that t-ZrO2 samples have two photoluminescence (PL) bands corresponding to the wavelengths of excitations of 254 and 412 nm. The structure of as-synthesized samples (ZrO2.nH(2)O) and the formation mechanism of ZrO2 nanopowders are also discussed. (C) 2002 Elsevier Science Ltd. All rights reserved.