LaMnO(3+delta) and La(0.7)Ca(0.3)MnO(3) were synthesized from La(2)O(3)(La(OH)(3)), CaCO(3) and MnO(2) powder mixture with solid-state reaction technique. X-ray diffraction and thermal analysis were employed in the present study on the process of synthesizing of the two compound powders. The kinetic study on solid-state reaction between La(2)O(3) and MnO(2) in the powder mixture was isothermally carried out for LaMnO(3+delta) formation. The result showed that the reaction process was controlled by three-dimensional solid-ionic diffusion. Both Jander and Ginstling-Brounstein model can be used to describe the reaction kinetics satisfactorily. The relevant apparent activation energy values obtained were as great as 205 +/- 11 and 189 +/- 8 kJ/mol. The reaction process of La(0.7)Ca(0.3)MnO(3) preparation from La(2)O(3), SrCO(3) and MnO(2) powder mixture was also studied using X-ray diffraction and thermal analysis. The result indicated that the following steps composed the overall reaction: the decomposition of the reactant; the formation of La(1-x)Ca(x)MnO(3+delta); La(2)O(3) and Mn(3)O(4) reacted with La(1-x)Ca(x)MnO(3) to form final La(0.7)Ca(0.3)MnO(3) phase. The latest step was the most time-consuming one among others in the overall reaction. (C) 2008 Elsevier Ltd. All rights reserved.