Non-random distribution of cations in Sn1-xTixO2 (0.0 <= x <= 1.0): a Sn-119 MAS NMR study

Mixed oxide samples of Sn1-xTixO2 (0.0 less than or equal tox less than or equal to1.0), prepared by the co-precipitation method followed by heating at variable temperatures, have been investigated by powder X-ray diffraction and Sn-119 MAS NMR spectroscopy. Based on powder X-ray diffraction studies, the formation of solid solutions has been observed for samples annealed up to approximate to 800 degreesC. Annealing of the samples with 0.2 less than or equal tox less than or equal to0.8 at higher temperatures led to their decomposition into two phases with a rutile structure, one being rich in Sn4+ and the other in Ti4+. Based on the comparison of the Sn-119 MAS NMR spectra of the single phase and phase separated compositions, it is inferred that the cation distribution is non-random even for the samples which exhibited single phase formation.