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 a t 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 u p to approximate to 800 degreesC. Annealing of the samples with 0.2 less th an or equal tox less than or equal to0.8 at higher temperatures led to thei r 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 s pectra of the single phase and phase separated compositions, it is inferred that the cation distribution is non-random even for the samples which exhi bited single phase formation.