Interhalogens anions

The reactivity of iodine has been investigated at liquid-liquid-electrode triple-phase boundary systems. Scholz et al. [162] demonstrated that the reduction of iodine dissolved in a nitrobenzene microdroplet triggered the transfer of cations from the aqueous into the organic solution phase (Scheme 6). In addition, the formation of IzCl" interhalogen anions in the organic phase was discovered and shown to be the key to the overall process. 

The halogens form many compounds and ions that are binary or ternary combinations of halogen atoms. There are three basic types (a) neutral interhalogen compounds, (b) interhalogen cations, and (c) interhalogen anions. 

Formation of these anionic species is not limited to species that contain only one halogen, and some interhalogen anions are also formed ... 

On the whole, the observed structures of interhalogen anions and cations (Table 16.4) are in accord with VSEPR theory, but [BrFg] is regular octahedral, and arguments reminiscent of those used in Section 15.7 to rationalize the structures of [SeClg] and [TeClg] appertain. Raman spectroscopic... 

The use of trihalide salts, including salts of interhalogen anions, as electrolytes in solar cells motivates current research in this area. In the pursuit of this objective, l,2-dimethyl-3-butylimidazolium iododibromide has been structurally characterized (Figure 8.39). ... 

C21-0093. Some pure liquid interhalogen compounds are good electrical conductors, indicating that they contain cations and anions. Show a Lewis acid-base reaction between two bromine trifluoride molecules that would generate ionic species. 

Numerous cases have been described elsewhere in which NO+ is produced, but the C1F2 represents an anion of an interhalogen. Polyhalide anions are not rare because when iodine is dissolved in a solution containing I-, the I3 ion is formed. 

In addition to the polyhalide ions discussed previously, which were all anionic, there are comparable cationic species known, although they have been studied considerably less. Many pure interhalogen compounds arc thought to undergo autoionization (see Chapter 10) with the formation of appropriate cationic species ... 

Many interhalogen and polyhalogen anions and cations are also known, some forming easily. For example, aqueous solutions containing I- dissolve I2 to form I-3. In liquid BrF3 the following equilibrium occurs ... 

The reactions of the interhalogen compounds are not greatly different from those of the halogens themselves. Hydrolysis of compounds in basic solution yield the halide ion derived from the smaller halogen and an oxy-halogen anion derived from the larger halogen thus, hydrolysis of BrF yields a 5 1 mixture of fluoride and bromate, Iodine monochloride... 

The interhalogens, particularly the halogen fluorides, are chemically very reactive materials and hydrolyze easily. The handling and manipulation of these, their derivatives, and cationic or anionic species have to be performed using the safety precautions customary in fluorine chemistry (exclusion of moisture and air, and in vacuum lines constracted from materials that are resistant to fluorine). The properties of the interhalogens are intermediate between those of their parent halogens, and some physical properties are summarized in Table 4. 

Cation formation is not restricted, as normally observed, to association with metallic species. It can also occm among nonmetals and even the most typical ones such as halogens or interhalogens, which are usually more noted for halide and polyhalide anion formation. 

Astatine interhalogens AtY (Y = Br and I) also react with H, Br, and Cl to form heteropolyhahde anions... 

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