Preparation, Structure and IR Spectra of Rare Earth Complex Oxides Nanocrystallines RE_2Sn_(2-x)B'xO_7(RE=Sm,Ce; B'=Fe,Co,Ni; x=0～1.0)

The new nanocrystallites of the pyrochlore-type of rare earth complex oaldes with B-site doped,RE2Sn2-xB'O7(RE=Sm,Ce; B'=Fe,Co,Ni: x=0～1-0), were prepared by unalcolate sol-gel method forthe first time. The nanocrystallite sizes were from 25 to 3Onm. It is found that this method can lowerreactive temperature (about 200℃) and shorten reactive time, The crystal structure of the nanocrystallitesbelongs to.cubic system and their lattice parameters are linear1y related to the content of doped ions. RomIR spectra, it is found that:(1) the data of absorption frequency of samples with RE=Ce are lower thanthat of with RE=Sm; (2) dopants of different ions in B-site not only bring about distortion of BO6octahedron, presenting relevant absorption, but also affect the vibration of RE-O bridge, causing lowerfrequency.