Ultrafine brucite Mg(OH)(2) nanostructures exhibiting wormhole-, tube-, rod- or platelet-like morphologies were prepared by pulsed laser ablation of an Mg plate target immersed in deionized water or aqueous solutions of sodium dodecyl sulfate (SDS) surfactant. The structure, morphology, and composition of the resultant Mg(OH)2 nanostructures were investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), and energy-dispersive X-ray spectroscopy (EDS). A possible formation mechanism of the Mg(OH)2 nanostructures is proposed based on the initial laser-induced reactive quenching process and subsequent surfactant-directing growth. (C) 2004 Elsevier B.V. All rights reserved.