Abstract: Ultrafine powders of hydroxides and oxides of thirteen rare earths have been praparedby alcoxide method. The size of the powder particle was less than 0.05μm by TEM observa-tion. The powders obtained from Jight rare earths are different in shapes from those fromheavy rare earths and are easier to be dispersed. XRD determination showed that the ultra-fine powders of some rare earth hydroxides are crystalline, while the powders of the oxidesare all crystalline.

Key words: hydroxide of rare earth, oxide of rare rare earth, ultrafine powder, preparation