Cerium dioxide

Cerium Oxide. The most stable oxide of cerium is cerium dioxide [1306-38-3] Ce02, also called ceria or ceric oxide. When cerium salts are calcined in air or if oxygen is present, this tetravalent Ce(IV) oxide is formed, cerium sesquioxide [1345-13-7] can be prepared in strongly reducing... 

Nitrobenzaldehyde has been prepared from />-nitrotoluene by treatment with isoamyl nitrite in the presence of sodium methylate,1 by oxidation with chromyl chloride,2 cerium dioxide,3 or chromium trioxide in the presence of acetic anhydride.4 It can also be prepared by the oxidation of -nitrobenzyl chloride,5 7>-nitrobenzyl alcohol,6 or the esters of -nitrocinnamic acid.7... 

Ceric Oxide (Cerium Dioxide, Cerium Oxide, Ceria). CeOj, mw 172.13, white powd, mp ca 2600°, d 7.132g/cc at 23°. Sol in coned sulfuric and nitric acids, insol in dil acids and w. Prepn is by dissolving CeCOj in 16N HNOa contg 3% H202 and then evapg off the nitrate soln followed by thermal decompn. The yield is 97.6% of 99.8% pure Ce02, The oxide is used in optics, electronics, as a diluent in nuclear fuels (as... 

Cerium diiodide, 20 4 Cerium dioxide, 20 67, 69, 73, 74 Cerium hydride, neutron diffraction studies on, 8 238... 

The unique properties of lanthanide-based materials, e.g., lanthanide-silicates and lanthanide-doped silicas, can be related to the special properties of the 4f" orbitals. Among lanthanide oxides, only Ce, Pr and Tb form dioxides, which crystallize in one simple structure with M4+ ions showing octahedral coordination [17]. For instance, cerium dioxide exhibits an 8 4 catiomanion coordination [18]. Its characteristic feature is the ability to undergo oxidation-reduction cycles in a reversible way [19], It was shown that the presence of Ce and La additives in mesoporous silicas, e.g., MCM-41 [10,11] and MSU-X [12], improves their thermal and hydrothermal stability. 

Arsenites of the Rare Earth Metals.—When cerium dioxide is heated with arsenious oxide some oxidation of the latter occurs, but the product appears to be a mixture of oxides.5 Didymium hydrogen orthoarsenite, Di2(HAs03)3, has been obtained6 as a white, granular, insoluble powder by boiling didymium hydroxide with an aqueous solution of arsenious oxide. Lanthanum hydrogen orthoarsenite, La2(HAs03)3, has been prepared in a similar manner. The existence of these compounds needs confirmation, however.7... 

Cerium Dioxide. See Ceric Oxide under Oxides... 

Reaction XCI. (c) Oxidation of Aromatic Hydrocarbons to Aldehydes by the Action of Cerium Dioxide in presence of Concentrated Sulphuric Add. 

D.R.P., 158609.)—Cerium dioxide has the property of oxidising aromatic hydrocarbons to aldehydes and no further. The addition of a reagent to combine with the aldehyde group as formed is unnecessary,... 

The Cei9034 phase was found when cerium dioxide was reduced by hydrogen in electron microscope. The diffraction pattern in the [211]p direction is given in Figure 35. There are 19 superstructure spots along the direction [4-21]p, and the electron diffraction pattern has the symmetry of the space group, PI. The unit cell is a triclinic with an inversion center as shown in Figure 35. 

FIGURE42 Oxidization of carbon monoxide by cerium dioxide and a reduced cerium higher oxide as a function of temperature. 

FIGURE 18 Average crystallite size measurement by X-ray line broadening. The width of characteristic X-ray lines decreases markedly as cerium dioxide powder is sintered. The crystallites grow from an initial size of 50 to 400 A after heating in air for several hours. 

Carbon (lampblack) P. 13 Carbon dioxide (cylinder or generator) P. 15, 71 Carbon tetrachloride E. 5 Cerium dioxide P. 50, 51 Cerium oxalate P. 49 Chlorine (cylinder or generator) P. 36,... 

Lo Nigro, R., Toro, R., Malandrino, G. and Fragala, I. L. (2003). Heteroepitaxial growth of nanos-tructured cerium dioxide thin films by MOCVD on a (001) Ti02 substrate. Chem. Mater. 15(7), 1434-1440. 

Oxygen (O2-) anion conductors - stabilized zir-conia, stabilized - bismuth oxide, - BIMEVOX, doped cerium dioxide, numerous perovskite-type - solid solutions derived from Ln(A)B (B") 03 (A = Ca, Sr, Ba B = Ga, Al, In B" = Mg, Ni, Co, Fe), La2Mo207 and its derivatives, pyrochlores based on Ln2Ti07. 

Cerium dioxide is preferred over other oxides because platinum is expensive and vanadium and iron oxides are poisons for FCC catalysts. Usually an aqueous solution of a cerium salt is used to impregnate a spinel base which is then calcined to obtain the Ce02 active form. We have found that a 10 to 12% Ce02 is sufficient for effective S02 oxidation(1). 

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