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

Abstract

Mixed oxide samples of Sn_1 − xTi_xO₂ (0.0 ≤ x ≤ 1.0), prepared by the co-precipitation method followed by heating at variable temperatures, have been investigated by powder X-ray diffraction and ¹¹⁹Sn MAS NMR spectroscopy. Based on powder X-ray diffraction studies, the formation of solid solutions has been observed for samples annealed up to ≈800°C. Annealing of the samples with 0.2 ≤ x ≤ 0.8 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 ¹¹⁹Sn 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.