Three morphological structures of neodymium hydroxide (Nd(OH)(3)) nanoparticles, i.e. cube, sphere, and oval-like, have been synthesized in microemulsion systems. Calcination of the Nd(OH)3 nanoparticles with different morphologies at 900 degrees C in air yields neodymium oxide (Nd2O3) nanoparticles with the same morphological structures as those of their Nd(OH)(3) precursors. The Nd(OH)(3) nanoparticles are characterized by DSC-TGA, XRD and TEM, and the Nd2O3 nanoparticles by XRD and TEM. The morphological structures of the Nd(OH)(3) and Nd2O3 nanoparticles are controlled via the variation of the molar ratio of H2O to CTAB (omega). Experimental results show that the stirring time has no effects on the morphological structures of the Nd(OH)(3) nanoparticles, but rather has a significant impact on the sizes of the Nd(OH)(3) nanoparticles under the same omega. Possible formation mechanisms of the morphological structure of Nd(OH)(3) are proposed and discussed. (c) 2010 Elsevier BM. All rights reserved.