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About Polonium

Polonium Bohr

Polonium was discovered by Marie and Pierre Curie in 1898 – the first new element discovered through the reduction of uranium ores, or pitchblende. It is relatively scarce in the Earth, as only 100 micrograms of polonium can be produced from one ton of uranium ore. The discovery of this element was predicated on the finding that after removing uranium and thorium from ore, the resulting material was actually more radioactive than the uranium or thorium itself. Because of its scarcity, polonium is now produced primarily through neutron bombardment of bismuth (209Bi) in a nuclear reactor. This bombardment creates 210Bi, and after decaying with a half-life of 5 days, and after decay, the resulting material is left as 210Po. Like many other radioactive elements, 210Po is used in radioisotope thermoelectric generators and had a hand in the Manhattan Project. Along with beryllium, polonium was one of the key ingredients in the detonator for the plutonium bomb, “Fat Man”.

Additional applications of polonium include its use as a characteristic neutron source, and use in antistatic devices for industry. When rolling paper, wire or sheet metal, static electricity is often generated. A particle emitter such as polonium is often present in specifically designed brushes to minimize this static electricity, though industry has mostly replaced polonium with less harmful beta particle emitters. Special care must be taken with industrial processes when using polonium in this fashion. Additionally, polonium is utilized in applications with comparable necessities, for example: brushes to remove dust from photographic film and camera lenses. Because of its short half-life, these industrial tools need to be replaced on a regular basis. Traces of 210Po can often be found in cigarettes, phosphate fertilizers, seafood, and even in trace amounts in indoor air. Of the 15,000-22,000 estimated lung cancer deaths in the United States every year attributed to radon, polonium is present in (and presumed to be the cause of) the majority of these cases.

Polonium, a metalloid, can readily create compounds with many other elements; however, most all polonium compounds are synthetically created with little applicability outside of the scientific community. Polonium has 33 isotopes observed in total, all of which are radioactive. The most stable isotope is 209Po with a half-life of 103 years, which then decays into lead through alpha decay. However, the most common isotopes of polonium are found widespread throughout Earth’s biosphere (in trace amounts), and is part of the naturally-occurring uranium decay chain.

Polonium Properties

Polonium Bohr ModelPolonium is a Block P, Group 16, Period 6 element. The number of electrons in each of polonium's shells is 2, 8, 18, 32, 18, 6 and its electron configuration is [Xe]6s24f145d106p4. The polonium atom has a radius of a measure of the size of its atoms, usually the mean or typical distance from the nucleus to the boundary of the surrounding cloud of electrons. Since the boundary is not a well-defined physical entity, there are various non-equivalent definitions of atomic radius. It is measured in picometres (pm)"> 168pm and its Van der Waals radius is 197pm. In its elemental form, CAS 7440-08-6, polonium has a silvery gray appearance. Polonium was first discovered by Madame Marie Curie and and Pierre Curie in 1898 who extracted it from pitchblende, a then known uranium source. Polonium is named after Madame Curie's birthplace of Poland. Polonium is produced during the decay of naturally occurring uranium-238. It has 33 isotopes, all of which are radioactive. Polonium 210 is a radioactive element with a half life of approximately 138.39 days. It occurs naturally and is widely distributed in small amounts in the earth's crust. Polonium's most stable isotope is Polonium 209 with a half life of 102 years. Polonium is now commercially produced by neutron bombardment of bismuth 209 isotopes.

Polonium-210 has been used as a heat source to power thermoelectric cells in satellites. Polonium-210 mixed or alloyed with beryllium is used in neutron sources. Polonium is also used to eliminate static electricity in machinery and to remove dust from camera lenses and film. Polonium is both toxic and radioactive. Polonium information, including properties, research, applications and other useful facts are discussed below. Scientific facts such as the atomic structure, ionization energy, abundance on earth, conductivity and thermal properties are also included.

Symbol: Po
Atomic Number: 84
Atomic Weight: 209
Element Category: post-transition metal
Group, Period, Block: 16 (chalcogens), 6, p
Color: silvery-gray/ silvery
Other Names: N/A
Melting Point: 254 °C, 489 °F, 527 K
Boiling Point: 962 °C, 1764 °F, 1235 K
Density: (alpha) 9.196 g·cm3
Liquid Density @ Melting Point: N/A
Density @ 20°C: 9.4 g/cm3
Density of Solid: 9196 kg·m3
Specific Heat: N/A
Superconductivity Temperature: N/A
Triple Point: N/A
Critical Point: N/A
Heat of Fusion (kJ·mol-1): 10
Heat of Vaporization (kJ·mol-1): 100.8
Heat of Atomization (kJ·mol-1): 141
Thermal Conductivity:  ? 20 W·m-1·K-1
Thermal Expansion: (25 °C) 23.5 µm·m-1·K-1
Electrical Resistivity: (0 °C) (?) 0.40 nΩ·m
Tensile Strength: N/A
Molar Heat Capacity: 26.4 J·mol-1·K-1
Young's Modulus: N/A
Shear Modulus: N/A
Bulk Modulus: N/A
Poisson Ratio: N/A
Mohs Hardness: N/A
Vickers Hardness: N/A
Brinell Hardness: N/A
Speed of Sound: N/A
Pauling Electronegativity: 2
Sanderson Electronegativity: N/A
Allred Rochow Electronegativity: 1.76
Mulliken-Jaffe Electronegativity: 2.48 (16.7% s orbital)
Allen Electronegativity: N/A
Pauling Electropositivity: 2
Reflectivity (%): N/A
Refractive Index: N/A
Chemical Properties
Electrons: 84
Protons: 84
Neutrons: 125
Electron Configuration: [Xe]6s24f145d106p4
Atomic Radius: 168 pm
Atomic Radius,
non-bonded (Å):
Covalent Radius: 140±4 pm
Covalent Radius (Å): 1.42
Van der Waals Radius: 197 pm
Oxidation States: 6, 4, 2, 2 (amphoteric oxide)
Phase: Solid
Crystal Structure: cubic
Magnetic Ordering: nonmagnetic
Electron Affinity (kJ·mol-1) 183.322
1st Ionization Energy: 812.1 kJ·mol-1
2nd Ionization Energy: N/A
3rd Ionization Energy: N/A
CAS Number: 7440-08-6
EC Number: N/A
MDL Number: N/A
Beilstein Number: N/A
SMILES Identifier: [Po]
InChI Identifier: InChI=1S/Po
PubChem CID: 6328143
ChemSpider ID: 4886482
Earth - Total: N/A
Mercury - Total: N/A
Venus - Total: N/A
Earth - Seawater (Oceans), ppb by weight: 2.00E-11
Earth - Seawater (Oceans), ppb by atoms: 6.00E-13
Earth -  Crust (Crustal Rocks), ppb by weight: N/A
Earth -  Crust (Crustal Rocks), ppb by atoms: N/A
Sun - Total, ppb by weight: N/A
Sun - Total, ppb by atoms: N/A
Stream, ppb by weight: N/A
Stream, ppb by atoms: N/A
Meterorite (Carbonaceous), ppb by weight: N/A
Meterorite (Carbonaceous), ppb by atoms: N/A
Typical Human Body, ppb by weight: N/A
Typical Human Body, ppb by atom: N/A
Universe, ppb by weight: N/A
Universe, ppb by atom: N/A
Discovered By: Pierre Curie and Marie Curie
Discovery Date: 1898
First Isolation: Willy Marckwald (1902)

Polonium Isotopes

Polonium (Po) has 33 isotopes, all of which are radioactive.

Nuclide Isotopic Mass Half-Life Mode of Decay Nuclear Spin Magnetic Moment Binding Energy (MeV) Natural Abundance
(% by atom)
188Po 187.999422(21) 430(180) µs [0.40(+20-15) ms] Unknown 0+ N/A 1433.86 -
189Po 188.998481(24) 5(1) ms Unknown 3/2-# N/A 1441.94 -
190Po 189.995101(14) 2.46(5) ms α to 186Pb; β+ to 190Bi 0+ N/A 1450.02 -
191Po 190.994574(12) 22(1) ms α to 187Pb; β+ to 191Bi 3/2-# N/A 1458.1 -
192Po 191.991335(13) 32.2(3) ms α to 188Pb; β+ to 192Bi 0+ N/A 1466.17 -
193Po 192.99103(4) 420(40) ms [370(+46-40) ms] α to 189Pb; β+ to 193Bi 3/2-# N/A 1474.25 -
194Po 193.988186(13) 0.392(4) s α to 190Pb; β+ to 194Bi 0+ N/A 1491.65 -
195Po 194.98811(4) 4.64(9) s α to 191Pb; β+ to 195Bi; IT 3/2-# N/A 1499.73 -
196Po 195.985535(14) 5.56(12) s α to 192Pb; β+ to 196Bi 0+ N/A 1507.81 -
197Po 196.98566(5) 53.6(10) s β+ to 197Bi; α to 193Pb (3/2-) N/A 1515.88 -
198Po 197.983389(19) 1.77(3) min α to 194Pb; β+ to 198Bi 0+ N/A 1523.96 -
199Po 198.983666(25) 5.48(16) min β+ to 199Bi; α to 195Pb (3/2-) N/A 1532.04 -
200Po 199.981799(15) 11.5(1) min β+ to 200Bi; α to 196Pb 0+ N/A 1540.12 -
201Po 200.982260(6) 15.3(2) min β+ to 201Bi; α to 197Pb 3/2- N/A 1548.2 -
202Po 201.980758(16) 44.7(5) min β+ to 202Bi; α to 198Pb 0+ N/A 1556.28 -
203Po 202.981420(28) 36.7(5) min β+ to 203Bi; α to 199Pb 5/2- N/A 1564.36 -
204Po 203.980318(12) 3.53(2) h β+ to 204Bi; α to 200Pb 0+ N/A 1572.44 -
205Po 204.981203(21) 1.66(2) h β+ to 205Bi; α to 201Pb 5/2- N/A 1580.51 -
206Po 205.980481(9) 8.8(1) d EC to 206Bi; α to 202Pb 0+ N/A 1588.59 -
207Po 206.981593(7) 5.80(2) h EC to 207Bi; α to 203Pb 5/2- 0.79 1596.67 -
208Po 207.9812457(19) 2.898(2) y EC to 208Bi; α to 204Pb 0+ N/A 1604.75 -
209Po 208.9824304(20) 102(5) y EC to 209Bi; α to 205Pb 1/2- 0.77 1612.83 -
210Po 209.9828737(13) 138.376(2) d α to 206Pb 0+ N/A 1620.91 -
211Po 210.9866532(14) 0.516(3) s α to 207Pb 9/2+ N/A 1628.99 -
212Po 211.9888680(13) 299(2) ns α to 208Pb 0+ N/A 1637.07 -
213Po 212.992857(3) 3.65(4) µs α to 209Pb 9/2+ N/A 1635.83 -
214Po 213.9952014(16) 164.3(20) µs α to 210Pb 0+ N/A 1643.91 -
215Po 214.9994200(27) 1.781(4) ms α to 211Pb; β- to 215Bi 9/2+ N/A 1651.98 -
216Po 216.0019150(24) 0.145(2) s α to 212Pb; β- to 216Bi 0+ N/A 1650.75 -
217Po 217.006335(7) 1.47(5) s α to 213Pb; β- to 217Bi 5/2+# N/A 1658.83 -
218Po 218.0089730(26) 3.10(1) min α to 214Pb; β- to 218Bi 0+ N/A 1666.9 -
219Po 219.01374(39)# 2# min [>300 ns] Unknown 7/2+# N/A 1665.67 -
220Po 220.01660(39)# 40# s [>300 ns] Unknown 0+ N/A 1673.75 -
Polonium (Po) Elemental Symbol

Recent Research & Development for Polonium

  • Hair as an indicator of the body content of polonium in humans: preliminary results from study of five male volunteers. Rääf CL, Holstein H, Holm E, Roos P. J Environ Radioact. 2014 Dec 31
  • A statistical approach to investigating enhancement of polonium-210 in the Eastern Irish Sea arising from discharges from a former phosphate processing plant. Dewar A, Camplin W, Barry J, Kennedy P. J Environ Radioact. 2014 Dec
  • Rapid preparation of polonium counting sources for alpha spectrometry using copper sulfide microprecipitation. Guérin N, Dai X. Anal Chem. 2013 Jul 2
  • Improving forensic investigation for polonium poisoning. Froidevaux P, Baechler S, Bailat CJ, Castella V, Augsburger M, Michaud K, Mangin P, Bochud FO. Lancet. 2013 Oct 12
  • Polonium (210Po), uranium (234U, 238U) isotopes and trace metals in mosses from Sobieszewo Island, northern Poland. Bory?o A, Nowicki W, Olszewski G, Skwarzec B. J Environ Sci Health A Tox Hazard Subst Environ Eng. 2012
  • Review of chemical and radiotoxicological properties of polonium for internal contamination purposes. Ansoborlo E, Berard P, Den Auwer C, Leggett R, Menetrier F, Younes A, Montavon G, Moisy P. Chem Res Toxicol. 2012 Aug 20
  • Excess of (210)polonium activity in the surface urban atmosphere. Part (1) fluctuation of the (210)Po excess in the air. D?ugosz-Lisiecka M. Environ Sci Process Impacts. 2015 Feb 11
  • Enrichment and particle size dependence of polonium and other naturally occurring radionuclides in coal ash. Sahu SK, Tiwari M, Bhangare RC, Pandit GG. J Environ Radioact. 2014 Dec
  • Unprecedented trapping of difluorooctamolybdate anions within an α-polonium type coordination network. Sharga OV, Lysenko AB, Handke M, Krautscheid H, Rusanov EB, Chernega AN, Krämer KW, Liu SX, Decurtins S, Bridgeman A, Domasevitch KV. Inorg Chem. 2013 Aug 5
  • A study on lead (210Pb) and polonium (210Po) contamination from phosphogypsum in the environment of Wislinka (northern Poland). Bory?o A, Olszewski G, Skwarzec B. Environ Sci Process Impacts. 2013 Aug
  • Mortality among mound workers exposed to polonium-210 and other sources of radiation, 1944-1979. Boice JD Jr, Cohen SS, Mumma MT, Ellis ED, Cragle DL, Eckerman KF, Wallace PW, Chadda B, Sonderman JS, Wiggs LD, Richter BS, Leggett RW. Radiat Res. 2014 Feb
  • Evaluation of sample pretreatment methods for analysis of polonium isotopes in herbal medicines. Sreejith SR, Nair MG, Rao DD. J Environ Radioact. 2014 Dec
  • (210)Polonium and (210)lead content of marine birds from Southeastern Brazil. Godoy JM, Siciliano S, de Carvalho ZL, Tavares DC, de Moura JF, Godoy ML. J Environ Radioact. 2014 Sep
  • Volatile dimethyl polonium produced by aerobic marine microorganisms. Bahrou AS, Ollivier PR, Hanson TE, Tessier E, Amouroux D, Church TM. Environ Sci Technol. 2012 Oct 16
  • Poisonous polonium. Ansoborlo E. Nat Chem. 2014 May
  • Excess of polonium-210 activity in the surface urban atmosphere. Part 2: origin of (210)Po excess. D?ugosz-Lisiecka M. Environ Sci Process Impacts. 2015 Feb 11
  • Ingestion of polonium ((210)Po) via dietary sources in high background radiation areas of south India. Arunachalam KD, Baskaran KV, Rao DD, Sathyapriya R, Annamalai SK, Kuruva JK, Hari S. Int J Radiat Biol. 2014 Oct
  • Polonium-210 and Caesium-137 in lynx (Lynx lynx), wolverine (Gulo gulo) and wolves (Canis lupus). Gjelsvik R, Holm E, Kålås JA, Persson B, Asbrink J. J Environ Radioact. 2014 Dec
  • Polonium-210 and selenium in tissues and tissue extracts of the mussel Mytilus galloprovincialis (Gulf of Trieste). Kristan U, Planinšek P, Benedik L, Falnoga I, Stibilj V. Chemosphere. 2015 Jan
  • Polonium-210 in marine mussels (bivalve molluscs) inhabiting the southern coast of India. Feroz Khan M, Godwin Wesley S, Rajan MP. J Environ Radioact. 2014 Dec