alpha-MnO2-type single-crystal nanorods were synthesized under hydrothermal conditions based on the redox reaction of KMnO4 in an acidic environment. Several reaction parameters, like the reaction temperature, the reaction time and the concentration of KMnO4 in the reaction mixture, were varied in order to determine their impact on the structure, the dimensions of the synthesized nanorods, and as well on their thermogravimetric properties. It was found that the reaction time has no significant influence on the diameter, although it has a strong influence on the length of the obtained nanorods. On the other hand, the concentration of KMnO4 in the reaction mixture has a strong impact on both the diameter and the length. With an increasing concentration of KMnO4 in the reaction mixture the average lengths and diameters of the isolated MnO2 nanorods are reduced. The change in dimensions of the synthesized nanorods is reflected in their thermogravimetric properties. (C) 2010 Elsevier Ltd. All rights reserved.