STRUCTURAL-ANALYSIS OF MIXED TIN OXIDES PRODUCED BY THE SOL-GEL METHOD

Mixed oxides SiO2/SnO2 with 80/20 nominal weight composition have been obtained by the sol-gel method with different precursors. X-ray diffr action and low temperature transmission Mossbauer spectroscopy have be en used to follow the structural evolution of the samples after treatm ents in the temperature range RT-1050 degrees C. The main results are that changes in the precursor nature and gel preparation affect the Sn (IV) homogeneity in the SiO2 matrix and that the use of Sn-alkoxides i ncreases the content of residual carbon which promotes reduction of Sn (IV) at intermediate temperatures.