In this work lanthanum hydroxide nanoparticles were synthesized by sonochemical method. La2O3
nanoparticles were obtained after calcination of the La(OH)3 nanoparticles precursor in air at 600 ◦C for
2 h. The effect of some parameters such as concentration of precursors, pulse time of sonication, time of
sonication, and addition of PEG as surfactant on the morphology and the particle size were studied. The asprepared products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM),
transmission electron microscopy (TEM), X-ray photoelectron spectrum (XPS) and Fourier transform
infrared (FT-IR) spectra.