The physico-chemical properties of ZrO2, MgO and admixtured (stabilized) zirconium dioxide are presented. The synthesis of stabilized ZrO2 was conducted in a low-temperature process. The catalysts obtained on the basis of zirconium dioxide were monophase materials of a regular structure. The lattice parameter of the materials did not differ much from the standard value. The character of the surface active centers was being changed as a result of the admixturing. Synthesized monophase materials of catalytic properties, Zr-Mg-O and Zr-Mg-Y-O, have many strong Lewis centers at surfaces. There appeared not only the stabilization of the regular polymorphous structure of ZrO2, but also a modification of catalytic properties of the materials when the basic admixture (MgO and Y2O3) was being introduced to basic zirconium dioxide.The authors present a mechanism of alcohol or aldehyde condensation to ketone at the surface of the materials with the participation of Lewis acidic centers. (C) 2003 Elsevier Science B.V. All rights reserved.