Polonium valence

The heaviest elements in every group of the Periodic Table have a special interest because of the marked change in properties which occurs in passing down a group thus, in the heaviest member, the maximum group valency is achieved with difficulty, if at all. In the sulfur family (group 6B), of which polonium is the heaviest member, there is the added interest of a gradation from nonmetallic to metallic properties. 

The treatment of polonium(lV) with nitric acid/potassium permanganate under reflux yields a sludge of manganese dioxide which contains all the polonium originally present the valency state is uncertain. Polonium (IV) in weighable amounts is not oxidized by persulfate, ceric salts or chlorine in alkaline solution (12), although trace scale work indicates that both ceric salts and dichromate do oxidize polonium to polonium(VI) (94). 

The formation of linear chains can be extended to two dimensions. Parallel LSh" chains lying side by side can be joined to a square net. One more singly occupied p orbital per Sb atom is needed. Formally, an oxidation, tSIv ISb , has to take place. Six valence electrons per atom are needed for the square net. Nets of this kind occur, for example, in YbSb2 (with Yb ). Starting from the square nets, another formal oxidation, iSb ISb, yields the primitive-cubic polonium-type structure, which is known as a high-pressure modification of arsenic. Therefore, five electrons per atom are needed for this structure. Remarkably, polonium itself has one electron per atom too many for its structure. 

The two heaviest members of Group 6A can lose electrons to form cations. Although they do not lose all six valence electrons because of the high energies that would be required, tellurium and polonium appear to exhibit some chemistry involving their 4+ cations. However, the chemistry of these Group 6A cations is much more limited than that of the Group 5A elements bismuth and antimony. 

Polonium is the most metallic member of group 6A. But it is not a typical metal. It is rare, radioactive, and extremely toxic. Polonium is important historically because it was discovered by Marie and Pierre Curie in 1898 and named for Marie s nabve land, Poland. Selenium and tellurium are metalloids oxygen and sulfur are nonmetals. There are some trends to note in group 6A. With six valence electrons, the elements act mainly as nonmetals. They tend to gain two electrons to form ions with a 2— charge they also can share two electrons to achieve a stable electron configuration. 

Polonium. Po at. wt of naturally occurring isotope 210 at. no. 84 valence 4. occasionally 2, rarely 6. Isotopes range in mass number from 193-218 all are radioac-... 

The Group VIA elements are oxygen, sulfur, selenium, tellurium, and polonium. They have a valence shell configuration of ns np. Oxygen (Oj) is a diatomic gas, and it also exists in an allotropic form called ozone (O3). Sulfur forms acidic oxides (e.g., SO, SO3). 

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