Cerium, oxidation with

Yellow. Cerium oxide with titanium oxide... 

Application of Raman spectroscopy to a study of catalyst surfaces is increasing. Until recently, this technique had been limited to observing distortions in adsorbed organic molecules by the appearance of forbidden Raman bands and giant Raman effects of silver surfaces with chemisorbed species. However, the development of laser Raman instrumentation and modern computerization techniques for control and data reduction have expanded these applications to studies of acid sites and oxide structures. For example The oxidation-reduction cycle occurring in bismuth molybdate catalysts for oxidation of ammonia and propylene to acrylonitrile has been studied in situ by this technique. And new and valuable information on the interaction of oxides, such as tungsten oxide and cerium oxide, with the surface of an alumina support, has been obtained. 

Fluorination of cerium oxide with NH4HF2 affords (NFi4)4[CeF8]. structure based on infinite chains of edge-sharing [TbFg] units. 

S. C. Laha and R. Ryoo, Synthesis of thermally stable mesoporous cerium oxide with nanocrystalline Ifameworks using mesoporous silica templates, Chem. Commun., 17,2138-9 (2003). 

When treating a mixture of lanthanum oxide and cerium oxide with 50-2(X) parts of nitric acid diluted with water, lanthanum oxide was dissolved, but the residual cerium oxide was not yellow, but brownish-red, and the lanthanum oxide also had a more or less similar reddish tint. From this phenomenon Mosander concluded that a third substance must be present, following in one experiment lanthanum oxide... 

Figure 25.3 The fee eell of cerium oxide with the fluorite structure. (Reprinted with permission from Ref. [12]. Copyright 1996, Tayior Francis.)...

A kind of more complicated metal oxide clusters, cerium oxide clusters are studied by Sierka s group. Ce202", Ce304 , and (Ce02)m CeO (m = 0-4) are unambiguously determined by a combination of GA-DFT method and infrared vibrational predissociation spectroscopy of the cluster-rare gas atom complexes. The most stable structures of even small gas-phase aggregates of cerium oxide with 2-5 cerium atoms show structural motifs reminiscent of the bulk ceria. This is different from main group and transition metal oxide clusters, which often display structural features that are distinctly different from the bulk structure. 

Figure 9.14a, b show the diffractograms after pretreatment of the sample with an inert atmosphere and after the reduction with H2 at 300 C. The two phases are of cubic cerium oxide, with fluorite-like structure (cerianite), and after reduction, dispersed tenorite (CuO) crystallites were reduced to metallic Cu. 

Figure 2.2. Schematic representation of cerium oxide with anion vacancies and Ce ions...

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