Page 295 - Arrow Pushing in Inorganic Chemistry A Logical Approach to the Chemistry of the Main Group Elements

7.8 INTERHALOGEN COMPOUNDS 275

REVIEW PROBLEM 7.15
Suggest mechanisms for the two FClO reactions in (7.63) above.
3

7.8 INTERHALOGEN COMPOUNDS

A fair number of interhalogen compounds with the general formula XY where n = 1, 3, 5,
n
or 7, are known, the more well-established ones being those listed in Table 7.1.
A couple of quick observations: For a given halogen X as the central atom, observe that
the choice of Y = F generally leads to the highest valence for X. Second, note that ICl 3
exists as a dimer, with two of chlorines acting as bridging ligands.

REVIEW PROBLEM 7.16
Draw a Lewis structure for (ICl ) .
3 2

A common reaction of the uncharged interhalogens is with powerful halide acceptors,
resulting in interhalogen cations:
+
−
ClF + AsF → [ClF ][AsF ] (7.64)
3
6
2
5
+ −
BrF + 2SbF → [BrF ][Sb F ] (7.65)
5
2 11
4
5
+
−
IF + BF → [IF ][BF ] (7.66)
3
6
7
4
Certain halogen fluorides also act as fluoride anion acceptors:
+
−
ClF + CsF → Cs [ClF ] (7.67)
2
−
+
ClF + CsF → Cs [ClF ] (7.68)
3
4
−
+
IF + CsF → Cs [IF ] (7.69)
7
8
TABLE 7.1 A List of Relatively Stable Interhalogens Containing No More than Two Different
Halogens
F Cl Br I
F F 2
Cl ClF, ClF ,ClF 5 Cl 2
3
Br BrF, BrF ,BrF 5 BrCl Br 2
3
I IF, IF ,IF ,IF ICl, (ICl ) IBr I
3 5 7 3 2 2