Ion-exchange reactions of aqueous SnCl2 center dot 2H(2)O Solutions with oxides such as H2Sb2O6 center dot 3.0H(2)O, KSbWO6, and KTaWO6 center dot 1.0H(2)O resulted in novel Sn2+ incorporated pyrochlore-type oxides under ambient conditions Characterization of the Sn2+ exchanged products by powder X-ray diffraction, EDAX, thermogravimetric analysis, and chemical analysis yielded nominal compositions of Sn0.92Sb2O6 center dot 2.0H(2)O, K0.59Sn0.20SbWO6 center dot 1.0H(2)O, and K0.58Sn0.29TaWO6 center dot 1.0H(2)O. Diffuse reflectance spectra of the oxides incorporated with Sn2+ ions clearly exhibited red shifts from their respective parent oxides. The observed reduction in the band gaps to an extent of 0.9-1.6 eV was consistent with the Sn2+ ion-exchange, and indicated the upward shifting of the valence band resulting from the contribution of 5s band of Sn2+ to the O 2p band. Photocatalylic activities of the synthesized pyrochlore oxides were consistent with their electronic properties and decomposed methyl orange (MO) solutions under visible light. The pseudo first order rate constants of the oxides Sn0.92Sb2O6 center dot 2.0H(2)O and K0.59Sn0.20SbWO6 center dot 1.0H(2)O for the decomposition of MO solutions were found to be 1.34 h(-1) and 0.217 h(-1), respectively, and almost a negligible MO decomposition was observed for K0.58Sn0.29TaWO6 center dot 10H(2)O. The photocatalytic efficiencies of the oxides were found to be proportional to the rate of formation of center dot OH radicals, which was found to vary in the order, Sn0.92Sb2O6 center dot 2.0H(2)O>K0.59Sn0.20SbWO6 center dot 1.0H(2)O>K0.58Sn0.29TaWO6 center dot 10H(2)O as determined by the photoluminescence spectra using terephthalic acid.