Chromyl fluoride

The pure, crystalline chromium (V) oxide trifluoride can be prepared by the reaction of xenon(II) difluoride and chromium (VT) dioxide difluoride [7788-96-7], also known as chromyl fluoride, Cr02F2 (56) ... 

Chromous chloride hexahydrate, 6 531 Chromous sulfate heptahydrate, 6 531 Chromyl chloride, molecular formula, properties, and uses, 6 561t Chromyl compounds, 6 526, 536 Chromyl fluoride, 6 535 Chromyl perchlorate, anhydrous, 18 279 Chronic asthmatic bronchitis, effect on heart, 5 107... 

A similar reaction occurs with HF to yield chromyl fluoride Cr02F2. However, fluorination with F2 yields the oxohalide, CrOF4. 

Reaction with potassium dichromate yields chromyl fluoride ... 

Dichloro- and 1,1-difluoroethene are hypofluorinated by hydrogen fluoride/chromium(Vl) oxide to give the corresponding 1,1,1-trihaloethanols,218 probably via in situ formation of chromyl fluoride (Cr02F2). which then electrophilically attacks the 7i-bond.205... 

Bromides and iodides give rise to the free halogens, which yield colourless solutions with sodium hydroxide if the ratio of iodide to chloride exceeds 1 15, the chromyl chloride formation is largely prevented and chlorine is evolved.J Fluorides give rise to the volatile chromyl fluoride, Cr02F2, which is decomposed by water, and hence should be absent or removed. Nitrites and nitrates interfere, as nitrosyl chloride may be formed. Chlorates must, of course, be absent. 

The addition of fluorine and a hydroxy group, i.e. formation of a 8-fluoro alcohol 1, can be carried out using oxygen difluoridc, as 1.430 hypofluorous acid, chromyl fluoride,... 

Chromyl fluoride, Cr02F2, made by fluorination of Cr02Cl2 or by the action of anhydrous HF on Cr03, is a very stable red-brown gas.34... 

W. P. Evans, when chromyl fluoride is heated E. Fremy, when heated potassium chromate is decomposed by chlorine W. Muller, when potassium chromate at a red-heat is decomposed by hydrogen chloride V. Kletzinsky, when potassium chlorochromate is melted J. C. Gentele, when potassium dichromate is decomposed at a high temp. R. Otto, when potassium dichromate is decomposed by hydrogen at an elevated temp. A. Ditte, and H. Schiff, when potassium didiromate is decomposed by fusion with sodium chloride and M. Prud homme, when potassium dichromate is heated. with tin. Crystals of chromic oxide are often produced as a kind of sublimate when mixtures containing chromic oxide are heated in closed vessels in pottery ovens. E. Wydler, and G. F. C. Frick also described the prepara-... 

K. Fischbeck and E. Einecke found that the cathodic polarization of ferrous, cuprous, calcium, and magnesium chromites produces chromic acid, whilst the other chromites are unaffected, and natural chrome ironstone behaves in a like manner, but other commercial chromites are reduced on cathodic polarization, and yield chromic acid on anodic polarization. Chromites behave as an intermediate electrode. 0. Unverdorben observed that chromyl fluoride, prepared by heating a mixture of fluorspar, lead chromate, and sulphuric acid, when passed into water, furnishes an aq. soln. of this oxide. The soln. was treated with silver nitrate, and the washed precipitate of silver chromate decomposed by hydrochloric acid. A. Mans said that anhydrous sulphuric acid or fuming sulphuric acid is not suited for the preparation because of its volatilization with the chromyl fluoride. 

G. T. Hartshorn found that benzoic acid is converted into difluobenzoic acid and V. OUveri, that toluene reacts as in the case of chromyl chloride, forming a black mass, which, with water, gives benzaldehyde. 0. Unverdorben found that mercury slowly decomposes the vapour of chromyl fluoride and W. P. Evans found that zinc or sodium reduces the vapour to chromium q.v.). 

The ability of chloride to form a chromyl compound is not unique within the halogens. When bromide and iodide are treated with sulfuric acid and dichromate, they are converted into their free halogens. But fluorides will under these conditions form volatile chromyl fluoride, C1O2F2, and therefore give a reaction similar to chloride. The mercury chloride does not respond to the test owing to its low solubility, and the formation of chromyl chloride is limited for lead, silver, antimony, and tin chloride for the same reason. Iodide in 1 15 relative to chloride will give free chlorine. The presence of nitrites and nitrates interferes, as nitrosyl chloride is formed. ... 

Electrophilic Addition.—The hydroxylation of alkenes, including several steroids, with osmium tetroxide has been reviewed. Addition of HOBr to the 19-functionalized-5a-cholest-6-enes (13) gave mixtures of the corresponding bromohydrins (14) and the 6,19-epoxides (15) whereas the analogous B-homo-compounds (16) gave only the 6,19-epoxides (17). Similar effects were noted for the related HBr- and HC104-catalysed opening of the 6a,7a-epoxides and it was observed that the predominant attack by the 19-0 atom [5(0)" attack] in the B-homo-series lay in the possibility of its linear approach with the C-6—Br or C-6—O bond. The reactions of chromyl chloride and chromyl fluoride with steroidal alkenes and dienes have been reported " and it was observed that the... 

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