Pentafluorides disproportionation reactions

Bromine monofluoride [13863-59-7], BrF, can be prepared by the direct reaction of Br2 and F2, but because it readily disproportionates it has never been prepared in pure form (57). However, BrF can be prepared in situ by the reaction of Br2 with AgF in benzene (58) or by the reaction of A/-bromoacetamide and HF in ether (59). BrF adds to simple alkenes at room temperature to give products of trans-addition. Bromine trifluoride [7787-71-5], BrF, can be formed from gaseous fluorine and Hquid bromine (60). Bromine pentafluoride [7789-30-2], BrF, is formed from the reaction of BrF vapor with gaseous fluorine at 200°C (60). The tri- and pentafluorides are commercially available. As strong fluorinating agents they are useful in... 

WF5 is obtained by quenching the products of reaction of W with WF6 at 800 to 1000 K. It disproportionates above 320 K into WF4 and WF6. Crystalline MoF5 and WF5 (and also WOF4) have the tetrameric structure common to many pentafluorides (Section 13-11). 

Sometimes one of the elements in a reactant appears in more than one product of a reaction and has in one product, a higher oxidation number than before the reaaion and in the other product, a lower oxidation number than before the reaaion. In this way, the same element is both oxidized and reduced, and the same compound is both the oxidizing agent and the reducing agent. This process is called disproportionation. For example, iodine monofluoride, IF, disproportionates into iodine and iodine pentafluoride in the following reaction ... 

The red liquid pentafluorophenoxotungsten(vi) pentafluoride (222) is formed from MesSi O CeFs and an excess of WFe at 0°C (c/. Vol. 2, p. 422) and also apparently by disproportionation of the cu-bis(pentafluorophenoxo)-compound (221) (Scheme 48), identified as one of the products from the reaction of WF with two moles of MesSi-O-CeFa. ... 

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