Abstract: The correlation between the catalytic activity and structure of Sn_0.8Mo_0.2 mixedoxides calcinated at diffrent temperatures has been investigated by using ESR, XPS and XRD techniques.The results show that at 100～300 ℃ molybdenum disperses on the surface ofrutile-type stannic oxide formed at 100℃, at 300～500℃ it gradually diffuses into SnO₂ and at 550℃ the interstitial solid solution forms, which exhibites the best catalytic activity inoxidation of butene.The substitution solid solution forms at 600℃.

Key words: Mo-Sn mixed oxide, structure, catalytic property, butene, oxidation