Polyatomic Halogen Cations

The existence of many well-known compounds in which chlorine, bromine, and iodine are found in the +1 oxidation state led to the assumption that the cations Cl+, Br+, and I+ are important and stable entities or at best as reaction intermediates. However, no evidence exists for monoatomic Cl+, Br+, and I+ as stable species.771,772 In contrast, a whole series of polyatomic halogen cations are known.773-776... 

Iodine heptafluoride reacts with AsF5 or SbF5 to form products containing the IF6+ cation. 16.4.3 Polyatomic Halogen Anions... 

As early as 1804 solutions of non-metals such as sulfur and iodine in oleums were reported to produce highly colored solutions but the nature of the solutes was unknown. From the mid 1960s, Gillespie s group adduced reliable evidence to indicate that solutions such as these and others in HS03F and HF contained the polyatomic halogen cations It, if", IJ, If, Brf and Brf and the chalcogen cations listed in Table 2. 

In this section, the polyatomic cations of group 17 elements (halogen and interhalogen cations and polycations), cations and polycations of group 16 elements (O, S, Se, and... 

Sb-H bonds, 489 Sb-halogen bonds, 489 Se-H bonds, 451 Se-halogen bonds, 451 Si-Br bonds, 465 Si-Cl bonds, 464 Si-F bonds, 464 Si-H bonds, 455 Si-1 bonds, 465 Sn-Br bonds, 475-476 Sn-Cl bonds, 475 Sn-F bonds, 475 Sn-H bonds, 473 Sn-1 bonds, 476 Te-H bonds, 453 Te-halogen bonds, 453 Rare gas complexes anions, 1452 cations, 1446-1452 neutrals, diatomic, 1429-1436 polyatomic, 1436-1446 Rb-contarnmg species neutrals, 557-559 Rb clusters, 559-562 Rb clusters, 562-563 Re-containing species neutrals,796-799 Re clusters, 799-801 Re clusters, 801 Rh-contarnmg species neutrals, 882-892 Rh clusters, 892-894 Ru-containing species neutrals, 840-848 Ru clusters, 849-851... 

In the halogen group, like in other groups of the periodic table, the heavier elements present more metallic and electropositive properties. It is therefore no wonder that the early observed spedes vdiidi were easiest to be prepared and identified were those containing iodine only. Iodine most readily releases an electron thus stsibilizing iodine cations. In the early studies it was assumed that the iodine cation exists as a mono-atomic one -I. But in later studies this assumption could not be confirmed and it was proven that no monoatomic halogen cations exist instead only polyatomic ones, such as I3,12 were identified. These earlier studies were reviewed by Arotsky and Symons ), whereas the later critics were included in the review by Gillespie and Mor-ton ) and therefore will not be repeated here. 

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