View source for Polonium

{{Elementbox_header | number=84 | symbol=Po | name=polonium | left=[[bismuth]] | right=[[astatine]] | above=[[tellurium|Te]] | below=[[ununhexium|Uuh]] | color1=#cccc99 | color2=black }}
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{{SI}}
{{EH}}

==Overview==
'''Polonium''' ({{pronEng|pəˈloʊniəm}}) is a [[chemical element]] that has the symbol '''Po''' and [[atomic number]] 84. A rare and highly [[radioactive]] [[metalloid]]<ref> http://www.chemicalelements.com/groups/metalloids.html </ref>, polonium is chemically similar to [[tellurium]] and [[bismuth]], and it occurs in [[uranium]] [[ore]]s. Polonium has been studied for possible use in heating [[spacecraft]].  It is unstable; all [[isotopes of polonium]] are radioactive. 
== Applications ==
When it is mixed or [[alloy]]ed with [[beryllium]], polonium can be a [[neutron 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 neutron trigger or initiator for [[nuclear weapon]]s. Other uses include
* Devices that eliminate static charges in [[textile]] mills and other places.<ref>http://news.bbc.co.uk/1/hi/england/1868414.stm</ref> However, [[beta decay|beta particle]] sources are more commonly used and are less dangerous.  A non-radioactive alternative is to use a high-voltage DC power supply to ionise air positively or negatively as required.<ref>http://www.thermo.com/eThermo/CMA/PDFs/Articles/articlesFile_16929.pdf</ref>
* <sup>210</sup>Po can be used as an atomic heat source to power [[radioisotope thermoelectric generator]]s via [[thermoelectric]] materials.
* Because of its very high toxicity, polonium can be used as a poison (see, for example, [[Alexander Litvinenko poisoning]]).

== History ==  	 
Also tentatively called "Radium F", polonium was discovered by [[Marie Skłodowska-Curie]] and her husband [[Pierre Curie]] in 1898<ref>{{cite journal|author = Curie P., Curie M.|title =. |journal = Comptes Rendus|year = 1898|volume=126|pages=1101}}</ref> and was later named after Marie Curie's native land of [[Poland]] ([[Latin]]: ''Polonia'').<ref>{{cite journal 
| title = Borders of the Nuclear World --- 100 Years After Discovery of Polonium 
| author = Pfützner M.
| journal = Acta Physica Polonica B
| volume = 30
| issue 5
| year = 1999
| pages = 1197
| url =http://adsabs.harvard.edu/abs/1999AcPPB..30.1197P}}</ref><ref>{{cite journal 
| title = The centennial of the 1903 Nobel Prize for physics
| author = Adloff J. P.
| journal = Radichimica Acta
| volume = 91
| issue 12
| year = 681-688
| pages = 2003
| doi = 10.1524/ract.91.12.681.23428}}</ref> 
Poland at the time was under Russian, Prussian, and Austrian [[Partitions of Poland|partition]], and did not exist as an independent country. It was Curie's hope that naming the element after her native land would publicize its lack of independence. Polonium may be the first element named to highlight a political controversy.<ref>{{cite journal 
| title = Chemical and Polish aspects of polonium and radium discovery
| author = Kabzinska K.
| journal = Przemysl Chemiczny
| volume = 77
| issue 3
| year = 1998
| pages = 104-107}}</ref>

This element was the first one discovered by the Curies while they were investigating the cause of [[uraninite|pitchblende]] [[radioactivity]]. The pitchblende, after removal of the radioactive elements [[uranium]] and [[thorium]], was more radioactive than both the uranium and thorium put together. This spurred the Curies on to find additional radioactive elements. The Curies first separated out polonium from the pitchblende, and then within a few years, also isolated [[radium]].

== Occurrence ==
Polonium is a very rare element in nature because of the short [[half-life]] of all its isotopes. It is found in [[uranium]] ores at about 100 [[microgram]]s per [[metric ton]] (1 part in 10<sup>10</sup>), which is approximately 0.2% of the abundance of radium. The amounts in the Earth's crust are not harmful.  Polonium has been found in [[tobacco smoke]] from tobacco leaves grown with phosphate fertilizers, though similar amount occur in everything from cherries to human tissue.<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>[http://kidslink.bo.cnr.it/besta/fumo/epolonio.html Alpha Radioactivity (210 Polonium) and Tobacco Smoke]</ref>

=== Synthesis by (n,<math>\gamma</math>) reaction ===

In [[1934]] an experiment showed that when natural [[bismuth|<sup>209</sup>Bi]] is bombarded with [[neutron]]s, <sup>210</sup>Bi is created, which then decays to <sup>210</sup>Po via β decay. Polonium may now be made in milligram amounts in this procedure which uses high neutron fluxes found in [[nuclear reactor]]s. Only about 100 grams are produced each year, practically all of it in Russia, making polonium exceedingly rare.<ref>http://www.rsc.org/chemistryworld/News/2006/November/27110601.asp RSC Chemistry World Q&A</ref> <ref>http://www.sptimesrussia.com/index.php?action_id=2&story_id=20100</ref>

=== Synthesis by (p, n) and (p,2n) reactions ===

It has been found that the longer-lived isotopes of polonium can be formed by [[proton]] bombardment of bismuth using a [[cyclotron]]. Other more neutron rich isotopes can be formed by the irradiation of platinum with [[carbon]] nuclei.<ref>{{cite journal| author = Atterling, H., Forsling, W.|title = Light Polonium Isotopes from Carbon Ion Bombardments of Platinum |journal = Arkiv for Fysik | volume = 15| issue = 1 | pages = 81-88 |year = 1959|url =http://www.osti.gov/energycitations/product.biblio.jsp?osti_id=4238755}}</ref>

== Isotopes ==
Polonium has [[Isotopes of polonium|25 known isotopes]], all of which are [[radioactivity|radioactive]].  They have [[atomic mass]]es that range from 194u to 218u. <sup>210</sup>Po (half-life 138.376 days) is the most widely available. <sup>209</sup>Po (half-life 103 years) and <sup>208</sup>Po (half-life 2.9 years) can be made through the alpha, proton, or deuteron bombardment of [[lead]] or [[bismuth]] in a [[cyclotron]].

=== <sup>210</sup>Po === 
<sup>210</sup>Po is an [[alpha decay|alpha emitter]] that has a half-life of 138.376 days; it decays directly to its [[decay product|daughter isotope]] [[lead|<sup>206</sup>Pb]].  A milligram of <sup>210</sup>Po emits about as many alpha particles per second as 4.5 grams of [[radium|<sup>226</sup>Ra]]. A few [[curie]]s (1 curie equals 37 [[Becquerel|gigabecquerels]]) of <sup>210</sup>Po emit a blue glow which is caused by [[excitation]] of surrounding air. A single gram of <sup>210</sup>Po generates 140 watts of power.<ref>[http://www.ead.anl.gov/pub/doc/polonium.pdf Polonium], Argonne National Laboratory</ref> Because it emits many [[alpha radiation|alpha particles]], 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 [[Radioisotope thermoelectric generator|thermoelectric cells]] in [[artificial satellite]]s; for instance,  <sup>210</sup>Po heat source was also used in each of the [[Lunokhod]] rovers deployed on the surface of the [[Moon]], to keep their internal components warm during the lunar nights.<ref>Andrew Wilson, ''Solar System Log'', (London:  Jane's Publishing Company Ltd, 1987), p. 64.</ref>  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> 

The majority of the time <sup>210</sup>Po decays by emission of an [[alpha particle]] only, not by emission of an alpha particle and a [[gamma ray]]. About one in 100,000 alpha emissions causes an excitation in the nucleus which then results in the emission of a gamma ray.<ref>http://atom.kaeri.re.kr/cgi-bin/decay?Po-210%20A</ref> This low gamma ray production rate (and the short range of alpha particles) makes it difficult to find and identify this isotope. Rather than gamma ray spectroscopy, alpha spectroscopy is the best method of measuring this isotope.
<!-- PLEASE DO NOT ADD        L I T V I N E N K O        HERE!

He is already mentioned below in the "Famous polonium poisoning cases" section -->

== Chemical characteristics ==
The chemistry of polonium is similar to that of [[tellurium]] and [[bismuth]]. Polonium dissolves readily in dilute [[acid]]s, but is only slightly [[solubility|soluble]] in [[alkali]]s. The hydrogen compound PoH<sub>2</sub> is liquid at room temperature ([[Melting point|M.P.]] -36.1°C to [[Boiling point|B.P.]] 35.3°C). [[Halide]]s of the structure PoX<sub>2</sub>, PoX<sub>4</sub> and PoX<sub>6</sub> are known. The two oxides PoO<sub>2</sub> and PoO<sub>3</sub> are the products of oxidation of polonium.<ref>Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001. ISBN 0-12-352651-5.</ref>

<sup>210</sup>Po (in common with [[Plutonium-238|<sup>238</sup>Pu]]) has the ability [[Volatility (chemistry)|to become airborne with ease]]: if a sample is heated in air to 328&nbsp;K (55°C, 131°F), 50% of it is vaporized in 45 hours, even though the melting point of polonium is 527&nbsp;K (254°C, 489°F) and its boiling point is 1235&nbsp;K (962°C, 1763°F).<ref>{{cite journal
| author = Bogdan Wąs, Ryszard Misiak, Mirosław Bartyzel, Barbara Petelenz 
| title = Thermochromatographic Separation of  <sup>206</sup>,<sup>208</sup>Po from a Bismuth Target Bombardet with Protons
| journal =Nukleonica
| year =2006
| volume =51
| issue = Suppl. 2
| pages = s3-s5
| url =http://www.ichtj.waw.pl/ichtj/nukleon/back/full/vol51_2006/v51s2p03f.pdf
}}</ref>
More than one hypothesis exists for how polonium does this; one suggestion is that small clusters of polonium atoms are [[spallation|spalled off]] by the alpha decay.

It has been reported that some [[microbe]]s can [[methylate]] polonium by the action of [[methylcobalamin]].<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>This is similar to the way in which [[mercury (element)|mercury]], [[selenium]] and [[tellurium]] are methylated in living things to create [[organometallic]] compounds. As a result when considering the biochemistry of polonium one should consider the possibility that the polonium will follow the same biochemical pathways as selenium and tellurium.

[[Image:alpha po lattice.jpg|thumb|right|The alpha form of solid polonium.]]

== Solid state form ==
The alpha form of solid polonium has a [[cubic (crystal system)|simple cubic]] crystal structure with an edge length of 3.352 Å.

The beta form of polonium is [[rhombohedral]]; it has been reported in the chemical literature, along with the alpha form, several times. A picture of it is present on the web.<ref>http://cst-www.nrl.navy.mil/lattice/struk/a_i.html</ref>

Two papers report X-ray [[diffraction]] 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 [[electron diffraction]].<ref>M.A. Rollier, S.B. Hendricks and L.R. Maxwell, ''Journal of Chemical Physics'', 1936, '''4''', 648-652.</ref>

== Tests ==
[[Image:Gammaspectrscopy.png|thumb|left|Intensity against photon energy for three isotopes.]]
{{-}}
===Gamma counting===
By means of radiometric methods such as [[gamma spectroscopy]] (or a method using a chemical separation followed by an [[activity (radioactivity)|activity]] measurement with a non-energy-dispersive counter), it is possible to measure the concentrations of [[radioisotopes]] 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 [[isotope]]. In biological/medical work it is common to use the natural [[potassium|<sup>40</sup>K]] present in all tissues/body fluids as a check of the equipment and as an internal standard.

[[Image:Alpha1spec.png|thumb|right|Intensity against alpha energy for four isotopes, note that the line width is narrow and the fine details can be seen.]]

[[Image:Alpha5spec.png|thumb|right|Intensity against alpha energy for four isotopes, note that the line width is wide and some of the fine details can not be seen. This is for liquid scintillation counting where random effects cause a variation in the number of visible photons generated per alpha decay.]]

===Alpha counting===
The best way to test for (and measure) many alpha emitters is to use [[alpha-particle spectroscopy]] as it is common to place a drop of the test solution on a metal disk which is then dried out to give a uniform coating on the disk. This is then used as the test sample. If the thickness of the layer formed on the disk is too thick then the lines of the spectrum are broadened, this is because some of the energy of the [[alpha particle]]s is lost during their movement through the layer of active material. An alternative method is to use internal liquid scintillation where the sample is mixed with a scintillation cocktail. When the light emitted is then counted, some machines will record the amount of light energy per radioactive decay event. Due to the imperfections of the liquid scintillation method (such as a failure for all the photons to be detected, cloudy or coloured samples can be difficult to count) and the fact that random quenching can reduce the number of photons generated per radioactive decay it is possible to get a broadening of the alpha spectra obtained through liquid scintillation. It is likely that these liquid scintillation spectra will be subject to a [[Gaussian broadening]] rather than the distortion exhibited when the layer of  active material on a disk is too thick.

A third energy dispersive method for counting alpha particles is to use a semiconductor detector.

From left to right the peaks are due to <sup>209</sup>Po, <sup>210</sup>Po, <sup>239</sup>Pu and <sup>241</sup>Am. The fact that isotopes such as [[plutonium|<sup>239</sup>Pu]] and [[americium|<sup>241</sup>Am]] have more than one alpha line indicates that the [[Atomic nucleus|nucleus]] has the ability to be in different discrete [[energy level]]s (like a molecule can).

== Toxicity ==
[[Image:Skull and crossbones.svg|left|80px]]
=== Overview ===

By mass, polonium-210 is around 250,000 (2.5*10<sup>5</sup>) times more toxic than [[hydrogen cyanide]] (the actual [[LD50|LD<sub>50</sub>]] for <sup>210</sup>Po is about 1 [[microgram]] for an 80 kg person (see below) compared to about 250 [[milligram]] for hydrogen cyanide<ref>[http://www.physchem.ox.ac.uk/MSDS/HY/hydrogen_cyanide.html Hydrogen cyanide msds]</ref>). The main hazard is its intense radioactivity (as an alpha emitter), which makes it very difficult to handle safely: one gram of Po will self-heat to a temperature of around 500 °C. Even in [[microgram]] 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 [[epidermis (skin)|epidermis]] and hence are not hazardous if the polonium is outside the body).

=== Acute effects ===

The median lethal dose ([[LD50|LD<sub>50</sub>]]) for acute radiation exposure is generally about 4.5 [[Sievert|Sv]].<ref name=pnl>http://www.pnl.gov/main/publications/external/technical_reports/PNNL-14424.pdf</ref> The [[committed effective dose equivalent (CEDE)|committed effective dose equivalent]] <sup>210</sup>Po is 0.51 µSv/[[Becquerel|Bq]] if ingested, and 2.5 µSv/Bq if inhaled.<ref name=nsds>[http://hpschapters.org/northcarolina/NSDS/210PoPDF.pdf Nuclide Safety Data Sheet: Polonium–210]</ref> Since <sup>210</sup>Po has an activity of 166 TBq (4486.5 Ci) per gram<ref name=nsds/> (1 gram produces 166×10<sup>12</sup> decays per second), a fatal 4.5 [[Sievert|Sv]]  (J/kg) dose can be caused by ingesting 8.8 MBq/kg (238 micro[[curie]]s, or about 24 mCi for 80 kg person), about 50 [[nanogram]]s per [[kilogram]] (ng/kg), or inhaling 1.8 MBq/kg (48 micro[[curie]]s, or about 4 mCi for 80 kg person), about 10 ng/kg. One gram of <sup>210</sup>Po could thus in theory poison 2 million (50 kg each) people of whom 1 million would die. The actual toxicity of <sup>210</sup>Po is lower than these estimates, because radiation exposure that is spread out over several weeks (the [[biological half-life]] of polonium in humans is 30 to 50 days<ref>[http://www.osti.gov/energycitations/product.biblio.jsp?osti_id=7162390 Effective half-life of polonium in the human]</ref>) is somewhat less damaging than an instantaneous dose. It has been estimated that a minimal [[LD50|lethal dose]] of <sup>210</sup>Po for an 80 kg person is 0.15 GBq (4 millicuries), or 0.89 micrograms, still an extremely small amount. <ref name=nuclearweaponsarchive>http://nuclearweaponarchive.org/News/PoloniumPoison.html</ref><ref>See also [http://www.iop.org/EJ/abstract/0952-4746/27/1/001 "Polonium-210 as a poison"]. "The conclusion is reached that 0.1–0.3 GBq or more absorbed to blood of an adult male is likely to be fatal within 1 month. This corresponds to ingestion of 1–3 GBq or more, assuming 10% absorption to blood".</ref>

=== Long term (chronic) effects ===

In addition to the acute effects, radiation exposure (both internal and external) carries a long-term risk of death from cancer of 5–10% per Sv.<ref name=pnl/> The general population is exposed to small amounts of polonium as a [[radon]] daughter in indoor air; the isotopes <sup>214</sup>Po and <sup>218</sup>Po are thought to cause the majority<ref>[http://fermat.nap.edu/openbook.php?record_id=1026&page=5 National Academy of Sciences 1988 report ''Health Risks of Radon and Other Internally Deposited Alpha-Emitters: BEIR IV'', page 5]</ref> of the estimated 15,000-22,000 lung cancer deaths in the US every year that have been attributed to indoor radon.<ref>[http://newton.nap.edu/html/beir6/ National Academy of Sciences 1999 report ''Health Effects Of Exposure To Indoor Radon'']</ref> [[Tobacco Smoking#Health risks of smoking|Tobacco smoking]] causes significant additional exposure to Po.<ref>[http://www.straightdope.com/columns/070928.html The Straight Dope ''Does smoking organically grown tobacco lower the chance of lung cancer?'']</ref>

=== Regulatory exposure limits ===

The maximum allowable body burden for ingested <sup>210</sup>Po is only 1,100 [[Bq]] (0.03 microcurie), which is equivalent to a particle weighing only 6.8 picograms. The maximum permissible workplace concentration of airborne <sup>210</sup>Po is about 10 Bq/m³ (3 × 10<sup>-10</sup> µCi/cm³).<ref>[http://www.nrc.gov/reading-rm/doc-collections/cfr/part020/appb/Polonium-210.html Nuclear Regulatory Commission limits for <sup>210</sup>Po]</ref> The target organs for polonium in humans are the [[spleen]] and [[liver]].<ref>http://www.pilgrimwatch.org/health1.html</ref> As the spleen (150 g) and the liver (1.3 to 3 kg) are much smaller than the rest of the body, if the polonium is concentrated in these vital organs, it is a greater threat to life than the dose which would be suffered (on average) by the whole body if it were spread evenly throughout the body, in the same way as [[caesium]] or [[tritium]] (as T<sub>2</sub>O).

<sup>210</sup>Po is widely used in industry, and readily available with little regulation or restriction.  In the US, a tracking system run by the Nuclear Regulatory Commission will be implemented in 2007 to register purchases of more than 16 curies of polonium 210 (enough to make up 5,000 lethal doses). The IAEA "is said to be considering tighter regulations... There is talk that it might tighten the polonium reporting requirement by a factor of 10, to 1.6 curies."<ref name="Zimmerman">{{Cite web|url=http://www.nytimes.com/2006/12/19/opinion/19zimmerman.html|title=The Smoky Bomb Threat|accessdate=2006-12-19|publisher=The New York Times|year=2006|author=Peter D. Zimmerman}}</ref>

=== Famous polonium poisoning cases ===

Notably, the murder of [[Alexander Litvinenko]], a Russian dissident, in 2006 was announced as due to <sup>210</sup>Po poisoning <ref>{{cite news | title=The mystery of Litvinenko's death |url=http://news.bbc.co.uk/1/hi/uk/6180432.stm | date=24 November 2006 | publisher=BBC News}}</ref><ref name="bbc">[http://news.bbc.co.uk/1/hi/uk/6698545.stm UK requests Lugovoi extradition] [[BBC News]]</ref> (see [[Alexander Litvinenko poisoning]]). According to Nick Priest, a radiation expert speaking on [[Sky News]] on [[December 2]], Litvinenko was probably the first person ever to die of the [[Acute (medical)|acute]] α-radiation effects of <sup>210</sup>Po.<ref>{{cite news |title=Focus: Cracking the code of the nuclear assassin |url=http://www.timesonline.co.uk/article/0,,2087-2484295_1,00.html}}</ref>

It has also been suggested that [[Irène Joliot-Curie]] was the first person ever to die from the radiation effects of polonium (due to a single intake) in 1956.<ref>Innocent chemical a killer - The Daily Telegraph (of Australia), [[December 4]], [[2006]] [http://www.news.com.au/dailytelegraph/story/0,22049,20863878-5001031,00.html]</ref> She was accidentally exposed to polonium in 1946 when a sealed capsule of the element exploded on her laboratory bench. A decade later, on [[17 March]] [[1956]], she died in Paris from [[leukemia]] which may or may not have been caused by that exposure.

According to the book ''[[The Bomb in the Basement]]'', several death cases in [[Israel]] during 1957-1969 were caused by <sup>210</sup>Po.<ref>
{{cite book
  | last = Karpin
  | first = Michael
  | authorlink = Michael Karpin
  | title = The bomb in the basement: How Israel went nuclear and what that means for the world
  | publisher = [[Simon and Schuster]]
  | date = 2006
  | id = ISBN 0743265947 }}
</ref>  A leak was discovered at a [[Weizmann Institute]] laboratory in 1957. Traces of <sup>210</sup>Po were found on the hands of Prof. [[Dror Sadeh]], a physicist who researched radioactive materials. Medical tests indicated no harm, but the tests did not include bone marrow. Sadeh died from [[cancer]]. One of his students died of leukemia, and two colleagues died after a few years, both from cancer. The issue was investigated secretly, and there was never any formal admission that a connection between the leak and the deaths had existed.

=== Treatment ===

It has been suggested that [[chelation therapy|chelation agents]] such as British Anti-Lewisite ([[dimercaprol]]) can be used to decontaminate humans.<ref>[http://www.osti.gov/energycitations/product.biblio.jsp?osti_id=4426335]9 also see NRCP Report No. 65: Management of Persons Accidentally Contaminated With Radionuclides</ref><ref>[http://www.fda.gov/cder/Guidance/6983fnl.pdf]</ref> In one experiment, rats were given a fatal dose of 1.45 MBq/kg (8.7 ng/kg) of <sup>210</sup>Po; 
all untreated rats were dead after 44 days, but 90% of the rats treated with the chelation agent 
HOEtTTC remained alive after 5 months.<ref>{{cite journal
  | author = Rencováa J., Svoboda V., Holuša R., Volf V., Jones M. M., Singh P. K. 
  | title = Reduction of subacute lethal radiotoxicity of polonium-210 in rats by chelating agents
  | journal = International Journal of Radiation Biology 
  | volume = 72
  | issue = 3
  | pages = 247 - 249
  | year = 1997
  | doi = 10.1080/095530097143338
}}</ref>

==See also==
* Polonium - Radon Decay Chain [http://www.cheec.uiowa.edu/misc/radon_occ.pdf] 
* [[Polonium halo]]

== References ==
<div class="references-small">{{reflist|2}}</div>

== External links ==
{{Commons|Polonium}}
{{wiktionary|polonium}}
References and External links verified [[2006-11-25]] unless noted.
*[http://www.webelements.com/webelements/elements/text/Po/index.html WebElements.com &ndash; Polonium]
*[http://www.globalsecurity.org/wmd/intro/polonium.htm History of Polonium]
*[http://periodic.lanl.gov/elements/84.html Los Alamos National Laboratory &ndash; Polonium] 
*[http://toxnet.nlm.nih.gov/cgi-bin/sis/search/r?dbs+hsdb:@term+@na+@rel+polonium,+radioactive NLM Hazardous Substances Databank &ndash; Polonium, Radioactive]
*[http://www.fas.org/sgp/othergov/doe/lanl/pubs/00326640.pdf The Human Plutonium Injection Experiments (Polonium experiments - pg20)]
*[http://www.techlib.com/science/ion.html#PoloniumPen Build a pocket-sized ion chamber, useful for detecting Polonium]

[[Category:Chemical elements]]
[[Category:Element toxicology]]
[[Category:Metalloids]]
[[Category:Chalcogens]]
[[Category:Carcinogens]]
[[Category:Polonium]]
{{SIB}}
[[af:Polonium]]
[[ar:بولونيوم]]
[[ast:Poloniu]]
[[bn:পোলোনিয়াম]]
[[be:Палоній]]
[[bs:Polonijum]]
[[bg:Полоний]]
[[ca:Poloni]]
[[cs:Polonium]]
[[co:Poloniu]]
[[da:Polonium]]
[[de:Polonium]]
[[et:Poloonium]]
[[el:Πολώνιο]]
[[es:Polonio]]
[[eo:Polonio]]
[[eu:Polonio]]
[[fa:پولونیوم]]
[[fr:Polonium]]
[[fur:Poloni]]
[[gl:Polonio (elemento)]]
[[ko:폴로늄]]
[[hy:Պոլոնիում]]
[[hr:Polonij]]
[[io:Polonio]]
[[id:Polonium]]
[[is:Pólon]]
[[it:Polonio]]
[[he:פולוניום]]
[[sw:Poloni]]
[[ht:Polonyòm]]
[[ku:Polonyûm]]
[[la:Polonium]]
[[lv:Polonijs]]
[[lb:Polonium]]
[[lt:Polonis]]
[[jbo:jicmrpoloni]]
[[hu:Polónium]]
[[ms:Polonium]]
[[nl:Polonium]]
[[ja:ポロニウム]]
[[no:Polonium]]
[[nn:Polonium]]
[[oc:Polòni]]
[[pl:Polon]]
[[pt:Polônio]]
[[ro:Poloniu]]
[[ru:Полоний]]
[[simple:Polonium]]
[[sk:Polónium]]
[[sr:Полонијум]]
[[sh:Polonijum]]
[[fi:Polonium]]
[[sv:Polonium]]
[[th:พอโลเนียม]]
[[tr:Polonyum]]
[[uk:Полоній]]
[[vi:Poloni]]
[[zh:钋]]
{{WH}}
{{WS}}