| 摘 要： | The solid state synthesis of the phase "Ce_3 NbO_(7+δ)",from stoichiometric quantities of CeO_2 and Nb_2 O_5,was investigated under air atmosphere,as previously described by Zhang et al.(Journal of Rare Earths,2007,25,730-733),A combination of powder X-ray diffraction,scanning electron microscopy with energy dispersive X-ray analysis,and laboratory Ce L_3 X-ray absorption spectroscopy,demonstrates the product of the reaction to be a mixture of CeO_2 and CeNbO_4.These data,and reexamination of the published X-ray diffraction data of "Ce_3 NbO_(7+δ)",are consistent with this phase in fact being CeO_2.No evidence for the formation of a phase of composition "Ce_3 NbO_(7+δ)" is found,by solid state synthesis under air atmosphere.
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