Polonium isotopes

Karraker, D. G., and D. H. Templeton Polonium Isotopes Produced with... 

Extension of the group VIb similarity to later members of the group (tellurium and polonium) is problematical. There are measurements of polonium isotopes in aerosols measured at a coastal site with both onshore and offshore winds (Kim et al., 2000), where the higher excess °Po in samples from air masses which have traveled over the oceans is attributed to volatilization of polonium from the sea surface. This could be by a process analogous to that already described for... 

The first example [33] was thorium emanation, Rn (diffusing from thorium compounds now known to contain Ra in approximate equilibrium with the ancestor radiothorium , Th), having exponential decay of its radioactivity with a half-life tjyj close to one minute. The weak point about the three emanations and their radioactive deposit (such as the polonium isotopes radium A , Po, and thorium A , Po) was the fact that their character as elements, rather than some kind of mobile ephemeral contamination, was only firmly established a few years later. 

This polonium isotope is radioactive and is a nonvolatile heavy metal that can attach itself to bronchial or lung tissue, emitting hazardous radiation and producing other isotopes that are also radioactive. 

What may be said about these branches The producers of natural astatine (the polonium isotopes) are by themselves extremely rare. For them alpha decay is not just predominant but practically the only radioactivity mechanism. Beta decays for them seem something like a mishap as can be clearly seen from the following data. 

There is only one beta decay event per 5 000 alpha decays of polonium-218. Things are even sadder for polonium-216 (1 per 7 000) and polonium-215 (1 per 200 000). The situation speaks for itself. The amount of natural francium on Earth is larger. It is produced by the longest-lived actinium isotope Ac (a half-life of 21 years) and its content is, of course, much higher than that of the extremely rare polonium isotopes capable of producing astatine. 

The half-life of the uranium isotope is about 1 X 10 times larger than the half-life of the polonium isotope. Unlike the rate constants for chemical reactions, moreover, the rate constants for nuclear decay are unaffected by changes in environmental conditions, such as temperature and pressure (see Table 17.1). 

Polonium is a rare, radioactive silver-gray metal that dissolves readily in dilute acids, but is only slightly soluble in alkalis. Because most polonium isotopes disintegrate by emitting alpha particles, the dementis a source of pure alpha radiation. 

Twenty-seven polonium isotopes, none of them stable, are now known, but only polonium-210 has been produced in sufficient quantities (milligrams) for chemical investigations. Due to its self-heating ability, polonium is a potential lightweight... 

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