Abstract

Nanocrystalline Ln2TeO6 (Ln = Y, La, Sm, Gd) have been prepared by a Pechini sol-gel process using lanthanide nitrates and telluric acid as precursors. All samples were characterized by X-ray diffraction (XRD), atomic force microscopy (AFM), Raman and Fourier transform infrared spectroscopy (FT-IR), as well as thermogravimetric analysis (TG). The AFM study reveals that the samples consist of particles with average crystal size ranging from 70 to 110 nm. The results of X-ray diffraction indicate that Ln2TeO6 (Ln = Y, La, Sm, Gd) crystallize isotypically with the orthorhombic La2TeO6 in the space group P212121. The infrared and Raman spectra show that the TeO6 groups are independent vibrating groups and the results obtained were discussed on the basis of the site symmetry analysis derivates from the structural data. © 2009 Elsevier B.V. All rights reserved.