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ItKillled a rusian Spy, that iS Nott good. I like fudge!
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'''Polonium''' (]: {{IPA|/pə(ʊ)ˈləʊniəm/}}) is a ] in the ] that has the symbol '''Po''' and ] 84. A rare ] ], polonium is chemically similar to ] and ] and occurs in ] ores. Polonium has been studied for possible use in heating ]. It exists as ].

== Applications ==
When it is mixed or ]ed with ], polonium can be a ] source: beryllium releases a neutron upon absorption of an alpha particle that is supplied by <sup>210</sup>Po. It has been used in this capacity as a ] for ]s. Other uses include:
* Devices that eliminate static charges in ] mills and other places. However, ] sources are more commonly used and are less dangerous. Another alternative is to use a high voltage direct current power supply to ionize air positively or negatively.
* Brushes that remove accumulated dust from ]s. The polonium used in these brushes is sealed and controlled thus minimizing radiation hazards.
* As <sup>210</sup>Po, a lightweight heat source to power ].

== History ==
Also called "Radium F", polonium was discovered by ] and her husband ] in ] and was later named after Marie's homeland of ] (]: ''Polonia''). Poland at the time was under Russian, Prussian and Austrian ], and not recognized as an independent country. It was Marie's hope that naming the element after her home land would add notoriety to its plight. Polonium may be the first element named to highlight a political controversy.

This element was the first one discovered by the Curies while they were investigating the cause of ] ]. The pitchblende, after removal of uranium and radium, was more radioactive than both radium and uranium put together. This spurred them on to find the element. The electroscope showed it separating with ].

== Occurrence ==
A very rare element in nature, polonium is found in ] ores at about 100 ]s per ] (1:10<sup>10</sup>). Its natural abundance is approximately 0.2% of the abundance of radium.

In ] an experiment showed that when natural ] is bombarded with ]s, <sup>210</sup>Bi, which is the parent of polonium, was created. Polonium may now be made in milligram amounts in this procedure which uses high neutron fluxes found in ]s. Only about 100 grams is believed to be produced each year, making polonium exceedingly rare.

Polonium has been found in ] from tobacco leaves grown with phosphate fertilizers.<ref>{{cite journal| author = Kilthau, Gustave F.|title = Cancer risk in relation to radioactivity in tobacco |journal = Radiologic Technology | volume = 67| issue = | pages = 217-222 |pim =8850254}}</ref><ref></ref>

== Isotopes ==
Polonium has ] all of which are ]. They have ]es that range from 194 u to 218 u. <sup>210</sup>Po is the most widely available. <sup>209</sup>Po (] 103 years) and <sup>208</sup>Po (half-life 2.9 years) can be made through the alpha, proton, or deuteron bombardment of ] or ] in a ]. However these isotopes are expensive to produce.

All elements containing 84 or more protons are radioactive. Alpha decay is a common form of decay for these nuclei. The most stable isotopes with more than 84 protons are ] and ]; which form an "]" which renders them stable enough to be found in large quantities in nature, but heavier nuclei are more and more affected by ].

=== <sup>210</sup>Po ===
This isotope of polonium is an ] that has a half-life of 138.376 days. A milligram of <sup>210</sup>Po emits as many alpha particles as 5 grams of ]. A great deal of energy is released by its decay with half a gram quickly reaching a temperature above 750 K. A few ]s (]) of <sup>210</sup>Po emit a blue glow which is caused by ] of surrounding air. A single gram of <sup>210</sup>Po generates 140 watts of power.<ref>, Argonne National Laboratory</ref> Because it emits many ], which are stopped within a very short distance in dense media and release their energy, <sup>210</sup>Po has been used as a lightweight heat source to power ] in ]s. A <sup>210</sup>Po heat source was also used in each of the ] rovers deployed on the surface of the ], to keep their internal components warm during the lunar nights. Some anti-static brushes contain up to 500 microcuries of <sup>210</sup>Po as a source of charged particles for neutralizing static electricity in materials like photographic film.<ref>http://www.amstat.com/solutions/staticmaster.html</ref>. <sup>210</sup>Po has very rare properties as an unstable isotope, as it decays only by emission of an ], not by emission of an alpha particle and a ].

== Chemical characteristics ==
Polonium dissolves readily in dilute ]s, but is only slightly ] in ]s. It is closely related chemically to bismuth and tellurium. <sup>210</sup>Po (in common with ]) has the ability to become airborne with ease (]), 50% of a sample is vaporized in air in 45 hours at 328K (55°C, 131°F) even though its melting point is 527K (254°C, 489°F) and its boiling point is 1235K (962°C, 1763°F). More than one hypothesis exists for how polonium does this; one suggestion is that small clusters of polonium atoms are ] by the alpha decay.

It has been reported that ] can ] polonium by the action of ].<ref>
{{cite journal
| author = Momoshima N., Song L.X., Osaki S.,Maeda Y.,
| title = Formation and emission of volatile polonium compound by microbial activity and polonium methylation with methylcobalamin.
| journal =Environ Sci Technol
| year =2001
| volume =35
| issue = 15
| pages = 2956-2960
| url =http://www.medscape.com/medline/abstract/11478248?prt=true|
| doi = 10.1021/es001730+ S0013-936X(00)01730-2}}
</ref><ref>
{{cite journal
| author = Momoshima N., Song L.X., Osaki S.,Maeda Y.,
| title = Biologically induced Po emission from fresh water
| journal =J Environ Radioact.
| year = 2002
| volume = 63
| issue = 2
| pages = 187-197
| doi =10.1016/S0265-931X(02)00028-0}}</ref>

== Solid state form ==
]
The alpha form of solid polonium is cubic with a distance of 3.352 Å between atoms. It is a simple ] solid which is not interpenetrated.

The beta form of polonium is ]; it has been reported in the chemical literature, along with the alpha form, several times.

Two papers report X-ray ] experiments on polonium metal.<ref>R.J. Desando and R.C Lange, ''Journal of Inorganic and Nuclear Chemistry'', 1966, '''28''', 1837-1846.</ref>
<ref>W.H Beamer and C.R. Maxwell, ''Journal of Chemical Physics'', 1946, '''14''', 569-569.</ref> The first report of the crystal structure of polonium was done using ].<ref>M.A. Rollier, S.B. Hendricks and L.R. Maxwell, ''Journal of Chemical Physics'', 1936, '''4''', 648-652.</ref>

== Tests ==
]
By means of radiometric methods such as ] (or a method using a ] followed by an ] with a non-energy-dispersive counter), it is possible to measure the concentrations of ] and to distinguish one from another. In practice, background noise would be present and depending on the detector, the line width would be larger which would make it harder to identify and measure the ]. In biological/medical work it is common to use the natural <sup>40<sup>K present in all tissues/body fluids as a check of the equipment and as an internal standard.

== Toxicity ==
Polonium is a highly radioactive and toxic element and is very difficult to handle.
Even in ] amounts, handling <sup>210</sup>Po is extremely dangerous, requiring specialized equipment and strict handling procedures. Alpha particles emitted by polonium will damage organic tissue easily if polonium is ingested, inhaled, or absorbed (though they do not penetrate the ] and hence are not hazardous if the polonium is outside the body).

To produce a ] of 10 ]s, if ingested, requires just 0.12 micrograms (millionths of a gram) of <sup>210</sup>Po (about 525 ] of radioactivity). A cube of pure <sup>210</sup>Po about the size of a written ] (0.35 mm wide, or 400 micrograms) would still be 3400 times the lethal dose. These calculations are based on a committed effective dose equivalent (CEDE) of 5.14{{e|&minus;7}} ]s per ] (1.9{{e|3}} mrem/microcurie) for ingested <sup>210</sup>Po and a specific activity of 1.66{{e|14}} Bq/gram (4.49{{e|3}} curies/gram).<ref></ref> If the polonium is inhaled, the CEDE is even higher, 2.54{{e|-6}} Sv/Bq or 9.43{{e|3}} mrem/microcurie, making the lethal dose just 106 microcuries or 0.026 micrograms.

The maximum allowable body burden for ingested polonium is only 1,100 ] (0.03 microcurie), which is equivalent to a particle weighing only 6.8 &times; 10<sup>-12</sup> gram. Weight for weight, polonium is approximately 2.5 &times; 10<sup>11</sup> (250&nbsp;billion) times as toxic as ]. The maximum permissible concentration for airborne soluble polonium compounds is about 7,500 Bq/m<sup>3</sup> (2 &times; 10<sup>-11</sup> µCi/cm<sup>3</sup>). The ] of polonium in humans is 30 to 50 days.<ref></ref>

==See also==
* ]
* The entry for polonium at ]
* ]
* ]

== References ==
<div class="references-small"><references /></div>

== External links ==
{{Commons|Polonium}}
{{wiktionary|polonium}}
References and External links verified ] unless noted.
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Revision as of 18:16, 28 November 2006

ItKillled a rusian Spy, that iS Nott good. I like fudge!