Single crystalline Ba1+xV6O16 center dot nH(2)O (x approximate to 0.2, n approximate to 3) nanobelts and a small quantity of seamless ring-like structures have been synthesized by a simple hydrothermal treatment of barium polyvanadate precursor. The nanobelts with a rectangular cross section are up to several tens of micrometers in length, 100-300 nm in width, and less than 50 nm in thickness. The ring-like structures with outer diameters of 3-5 mu m have several different types, such as plate-like, tube-like, doughnut-like and wheel-like morphologies. A probable mechanism for the formation of Ba1+xV6O16 center dot nH(2)O nanobelts and ring-like structures is proposed. (c) 2006 Elsevier B.V. All rights reserved.