In this paper. the preparation and characterization of crystalline terbium oxide via thermal decomposition of acetate precursor is reported. The decomposition pathway of the parent salt was followed using TGA, DTA, and in situ electrical conductivity in air and nitrogen atmospheres. The obtained results indicated that, thermal decomposition of terbium acetate proceeded with the loss of water molecules, in two steps, below 150 degrees C followed by decomposition in the temperature range of 300-550 degrees C. throughout different intermediates, to give Tb4O7 as a final product. The calcination products, obtained by heating the parent salt for 3 h in air at various temperatures, were characterized using IR, XRD, SEM, nitrogen adsorption, and electrical conductivity measurements. It was demonstrated that Tb4O7 represents the major phase for the samples calcined at 600-900 degrees C. The role of Tb3+-Tb4+ redox couple in enhancing the electrical conductivity of the calcination products was also discussed. (C) 2009 Elsevier B.V. All rights reserved.