Vanadium pentafluoride

Vanadium pentafluoride replaces benzylic hydrogen by fluonne but also adds fluonne to the aromatic system, giving fluonnated cyclohexadienes and cyclohexenes [5] (equation 5)... 

The V—F—V angle of 150° in the vanadium pentafluoride structure lies between those for the niobium and rhodium compounds. Thus, the structure cannot be described in terms of either of the close-packed arrangements. Although in the structure some approach toward close-packed planes of fluorine atoms can be seen, a comparison of volume per formula unit for the pentafluorides shows that for the second and... 

Vanadium Pentafluoride, VFs. Vanadium pentafluoride is the only pentahalide so far reported. It is best prepared by direct reaction between metallic vanadium and fluorine in a flow system at 300 °C under moisture free conditions. It is an extremely reactive white solid at room temperature and an extremely powerfiil oxidizing and fluorinating agent. 

In addition to the antimony fluorides, silver, mercury, thallium, aluminium, zinc, zirconium, chromium and other fluorides [7] such as mercury(II) fluoride, vanadium pentafluoride [24] and various transition metal oxide fluorides [25] have been used in exchange processes, although much less widely. 

Of course, most reactive metal fluorides, such as cobalt trifluoride [268] and vanadium pentafluoride, will react with alkenes but the reactions can be very difficult to control, except for haloalkenes [269]. Much easier control is possible with xenon fluorides [137], the reactivity decreasing in the series XeFe > Xep4 > Xep2. Since the first report of the use of xenon difluoride for the addition of fluorine to double bonds, many studies have been published and reviewed [54, 135] (Figure 3.61). 

In one of the studies of VCl, the Cl Cl vibrational amplitude was found to be abnormally large compared with that in TiCl4, and spectroscopic evidence is given supporting the view that the anomaly may be attributed to vibronic interaction in VQ4. Vanadium pentafluoride is trigonal bipyiamidal with V-F (mean) = 1.71 0.01 A. Ferric chloride, FeClj, is monomeric between 650 and 800 °C with Fe-Cl = 2.14 0.01 A supposedly it decomposes at 900 C to ferrous chloride, FeCl2, which has Fe-Cl = 2.17 0.01 A. 

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