A variant of the sol-gel technique known as cation complexation is used to prepare a nanocrystalline Gd0.1Ce0.9O1.95 (CDC) solid solution. A range of techniques including thermal analysis (TGA/DTA), Xray diffraction, specific surface area determination (BET) and electron microscopy (SEM and TEM) are employed to characterise the CDC powders. CDC calcined at 500 degrees C is found to have an average crystallite size of 11 nm. Specific surface areas are found to be 29.7 m(2) g(-1) for the as-calcined powder and 57.5 m(2) g(-1) after ball milling at 400 rpm. Dense ceramic pellets are prepared from unmilled and ball-milled CDC powders employing different thermal treatments. Their electrical properties are studied by impedance spectroscopy. Those samples sintered at 1300 degrees C for 30h (starting from ball-milled powders) exhibit the highest density (96% of theoretical density)and the highest total ionic conductivity (1.91 X 10(-2) S cm(-1) at 600 degrees C). (c) 2008 Elsevier B.V. All rights reserved.