Oxides and Oxyfluorides of the Halogens

The heavier halogens form a large number of oxides and oxyfluorides (Table 17.4). Most arc rather strong oxidizing agents and some are extremely unstable. These will... 

Oxyfluorides are the most stable of the oxyhalides, and the stability decreases with increasing atomic weight of the halogen. Special methods are used in the preparation of oxyfluorides, while the other oxyhalides can be prepared by general reactions, such as the partial hydrolysis of the pentahalides, or the oxidation of the trihalides. The compounds fume in the air and readily undergo further hydrolysis giving hydrogen halides and oxyaeids of phosphorus. 

A number of oxyhalides have structures which are similar to those of halides, some of the halogen atoms being replaced by 0 atoms. Since many of the ionic 3D structures of Table 10.11 are adopted by both fluorides and oxides, many of the oxyfluorides listed therein could be included here. If, however, we restrict ourselves here to structures which are peculiar to halides (that is, are not adopted by oxides) the known examples are those of Table 10.13. 

Little is known of the structures of the oxyfluorides listed in Table 9.6. Compounds XO2F are formed by all three halogens (Cl, Br, and I) and possibly also XO3F, since IO3F has been reported. The iodine compounds include the oxide pentafluoride, a type of compound also formed by Re and Os. A m.w. study indicates C/ symmetry, and presumably therefore the octahedral structure (e). 

We have seen that Bip3 is structurally different from all other trihalides of As, Sb, and Bi. Similarly, Bi oxyfluorides, with the exception of BiOF, are not related structurally to the compounds formed by Bi (or Sb) with the other halogens. Oxidation of Bip3 gives the following oxyfluorides, the structures of which are described elsewhere as indicated ... 

Five oxyfluorides of both chlorine i i2 and iodine and three of bromine have been characterized. They resemble the related halogen fluorides both structurally and chemically. They tend to be strong fluorinating and oxidizing agents. Many behave as both Lewis acids and bases, being able to donate... 

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