ChemInform Abstract: HOMOPOLYATOMIC CATIONS OF THE ELEMENTS

Abstract

Publisher Summary During the last 10 years, a number of homopolyatomic cations (M y x+ , where x ≤ y) have been prepared and characterized. For a long time, the only known example of this type of species was the mercurous ion Hg 2 2+ , but this can no longer be regarded as a chemical oddity, as it has now been joined not only by the analogous species Zn 2 2+ , and Cd 2 2+ , but also by Hg 3 2+ , and many cations of the nonmetals such as I 2 + , O 2 + , S 8 2+ , and Te 4 2+ . It is not surprising that some of the earliest examples of this type of cation— that is, O 2 + and Bi 9 + , were discovered quite accidentally, but it is perhaps surprising that some of the species have been known for at least 160 years, but were not recognized as such. For example, during the early nineteenth century, it was reported that sulfur, selenium, and tellurium dissolve in concentrated sulfuric acid or in oleum (H 2 SO 4 –SO 3 ,) to give various highly colored solutions. The origin of these colors was never clearly established, but it has now been shown that they are due to various polyatomic cations of these element, such as S 8 2+ , Se­ 4 2+ , and Te 4 2+ . Chemists have long been fascinated by the possibility that elements, such as iodine might be obtained in the cationic form I + as well as in the well-known anionic form I