Xonotlite (Ca6Si6O17(OH)(2)) nanobelts were synthesized by a microwave-assisted hydrothermal method at 180 degrees C for 90 min independent of the feeding molar ratio of Ca(NO3)(2)center dot 4H(2)O to Na2SiO3 center dot 9H(2)O in the range of 0.8-3.0. Crystalline wollastonite (beta-CaSiO3) nanobelts were obtained by microwave thermal transformation of Ca6Si6O17(OH)(2) nanobelts at 800 degrees C for 2 h. Ca6Si6O17(OH)(2) nanobelts were used as both the precursor and the template for the preparation of beta-CaSiO3 nanobelts. The morphology and size of Ca6Si6O17(OH)(2) nanobelts could be well preserved during the microwave thermal transformation process. The products were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM) and selected area electron diffraction (SAED). (C) 2009 Elsevier Ltd. All rights reserved.