Crystallization of rare earth carbonate nanostructures in the reverse micelle system

In this paper, a series of rare earth carbonate nanostructures were synthesized in the reverse micelle system and the influences of experimental conditions on the growth of the product crystals were investigated. Experimental results show that the decrease in rare earth ionic radii leads to gradual changes in the morphologies of the corresponding carbonates. One-dimensional carbonate nanowires were synthesized for La and Ce, whereas carbonate with zigzag morphology was prepared for Pr. In the region of Nd-Ho and for Y, complex fanlike nanostructures were obtained; with the decrease in ionic radii, the length of the fan reduced and the profile of the fanlike sector increased. For Er and Yb, ellipselike mesocrystals and white gel could be obtained, respectively. The evolvement of morphology indicates a change of the interactions between rare earth ion and the template molecule as well as possible conformational effects on the long-chain template molecules. Different morphologies of Ce-2(CO3)(3) and Eu-2(CO3)(3) were synthesized and a fractal growth mechanism was proposed for the formation of fanlike Eu-2(CO3)(3) nanostructure. It is herein shown that the crystal structure has an important influence on the control of the nanocrystal morphology. The experimental results reveal that the morphology of rare earth carbonates can be controlled through regulating the interaction between the corresponding ion or nanocrystal and the template molecule.