Carbonyl bromide fluoride

The asymmetrical, fluorine-containing carbonyl halides, COXF (X = Cl, Br or I) were first prepared and examined by Kwasnik at I.G. Leverkusen (a part of I.G. Farbenindustrie) during World War II. This work was later disclosed by RUdorff [1751], and by Fischer [656a] in the enemy-property confiscation reports, known as the FIAT Reviews of German Science. 

Under normal conditions of temperature and pressure, carbonyl bromide fluoride is a gas. Although colourless in both the gaseous and condensed states, it has been noted to develop a red-brown appearance within a few weeks when stored at room temperature (20 C), and storage in quartz ampoules cooled in low-boiling refrigerants (or in pressurized stainless steel cylinders) is recommended [1195]. Despite the observation of this 

Dibromine contamination can be removed by passing the impure carbonyl bromide fluoride over antimony powder [1SS5], and then COBrF can be purified by fractional distillation 

COBrF is described [1751] as having an odour similar to that of phosgene, and 

No toxicological data have been recorded for COBrF, and no Occupational Exposure Limits have been recommended. Although it is undoubtedly an irritant with a lethai capacity, it is unlikely to be as poisonous as phosgene. It is unlikely to be flammable. COBrF is not a commercially available substance, and it is not included in the European inventory of existing chemical substances (EINECS) [602a]. 

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The synonyms of carbonyl bromide fluoride include carbonic bromide fluoride (ACS nomenclature), carbonyl bromofluoride, carbon oxybromide fluoride and bromofluorophosgene. The lUPAC name is carbonyl bromide fluoride. The Chemical Abstracts Registry number for COBrF is [753-56-0]. 

Only a few of the physical properties of COBrF have been measured. Carbonyl bromide fluoride (relative molecular mass 126.91) is a colourless gas, with an odour similar to, but distinguishable from, phosgene [1195]. The melting point at atmospheric pressure of COBrF has been reported as -120 2 C [1196a], and the boiling point as -20.6 "C [1196a]. Its critical temperature occurs at +124 C, and its critical pressure is ca. 6.18 MPa [656a,1751]. 

The saturated vapour pressure of liquid carbonyl bromide fluoride is illustrated in Fig. 16.5 as a function of temperature, and is derived from the data points (Table 16.13) as measured by Kwasnik and reported by Fischer [656a]. 

The only solid state property on record for carbonyl bromide fluoride is its melting point -120 i 2 C [1196a]. 

There are no structural data known for carbonyl bromide fluoride. In particular, the microwave spectrum of COBrF has not been recorded, and no X-ray diffraction or electron diffraction studies have been performed. For this reason, the geometries of the molecule in the gas, liquid or solid phases are unknown, and calculations on COBrF that have required bond length and bond angle data have been performed using the known parameters of "closely related" molecules, or from geometry optimization calculations [2251b,2251c]. 

Carbonyl bromide fluoride is decomposed by passage of the vapour over activated charcoal according to Equation (16.12) [ICI112] ... 

Commercially unavailable, carbonyl bromide fluoride can be prepared by the oxidation of... 

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