Bismuth sesquioxide

Bismuth sesquioxide, BijOj, exhibits a high oxide ion conductivity at high temperature without doping of aliovalent cations. The oxide transforms from the monoclinic... 

Bismuth sesquioxide, Bi203, in the presence of acetic acid, oxidizes acyloins to a-diketones in high yields [481]. 

A very suitable oxidant for the conversion of acyloins into a-diketones is ammonium nitrate in the presence of catalytic amounts of cupric acetate. This reagent converts benzoin into benzil in 90% yield [476], The same result is obtained with bismuth sesquioxide 481] and sodium bromate 740 (equation 450). On the other hand, ceric ammonium nitrate does not give benzil but cleaves the bond between the alcoholic and the keto groups and cleaves benzoin into benzaldehyde and benzoic acid [425]. 

Synonyms Bismite Bismuthous oxide Bismuth (III) oxide Bismuth (3+) oxide Bismuth sesquioxide... 

Fluorite-type, rfaombohedral-type bismuth sesquioxide... 

Trivalent Compounds.—In trivalent vanadium compounds the basic character of the element is well developed, and both normal and oxy-salts of the sesquioxide V203 are well defined, e.g. vanadous sulphate, V2(S04)3, and vanadium oxymonochloride, VOC1. It has been previously mentioned that resemblances between the elements of the A and B Subdivisions of Group V. are mainly restricted to the pentavalent compounds it is of interest to note that the oxychloride has analogues in the trivalent antimony and bismuth basic chlorides, SbOCl and BiOCl. Trivalent vanadium also displays considerable analogy, however, with other trivalent transitional elements, as shown by the following —... 

A2Pt207, similar to those reported for tin, ruthenium, titanium, and several other tetravalent ions. Trivalent ions which form cubic platinum pyrochlores range from Sc(III) at 0.87 A to Pr(III) at X.14 A. Distorted pyrochlore structures are formed by lanthanum (1.18 A) and by bismuth (1.11 A). Platinum dioxide oxidizes Sb203 to Sb2(>4 at high pressure. The infrared spectra and thermal stability of the rare earth platinates have been reported previously and will not be repeated here, except to point out the rather remarkable thermal stability of these compounds decomposition to the rare earth sesquioxide and platinum requires temperatures in excess of 1200 °C. 

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