Bromine fluoride, BrF

R2C—0 - R2CF2. This reaction has been carried out directly with diethyl-aminosulfur trifluoride (DAST, 6, 183-184). It can also be effected by reaction of hydrazones of aldehydes or ketones with bromine fluoride, BrF, generated in situ from NBS and Py(HF)n. Yields from reactions of hydrazones of ketone are in the range 30-95% the yield from reaction of the hydrazone of an aldehyde was 28%. 

Bromine fluoride, BrF. BrF is conveniently formed from Br2 in C1,CF and used directly. 

Electrostatic forces between two ions decrease by the factor 1/cP as their separation, d, increases. But dipole-dipole forces vary as l/r/. Because of the higher power of d in the denominator, l/r/ diminishes with increasing d much more rapidly than does l/d. As a result, dipole forces are effective only over very short distances. Furthermore, for dipole-dipole forces, q+ and q represent only partial charges, so these forces are weaker than ion-ion forces. Average dipole-dipole interaction energies are approximately 4 kj per mole of bonds. They are much weaker than ionic and covalent bonds, which have typical energies of about 400 kJ per mole of bonds. Substances in which permanent dipole-dipole interactions affect physical properties include bromine fluoride, BrF, and sulfur... 

The actual composition present in the Brj/BrFa mixture is not known, and any fluorination reaction may be a composite reaction of BrF, BrFs and ErF. It is not necessary to assume that BrFj is the reactive constituent, although this is probable. Consider the fluorination of a species X—a metal, oxide, oxysalt, halide, etc.—to the fluoride XF by a mixture of bromine fluorides BrF[Pg.13]

The halogens form a series of compounds with each other, which are called interhalogens. Examples are bromine chloride (BrCl), iodine bromide (IBr), bromine fluoride (BrF), and chlorine fluoride (CIF). Which compound is expected to have the lowest boiling point at any given pressure Explain. 

---