{"id":189,"date":"2020-04-09T09:48:37","date_gmt":"2020-04-09T09:48:37","guid":{"rendered":"https:\/\/thechemicalelements.com\/?page_id=189"},"modified":"2023-08-15T15:10:44","modified_gmt":"2023-08-15T15:10:44","slug":"polonium","status":"publish","type":"post","link":"https:\/\/thechemicalelements.com\/polonium\/","title":{"rendered":"Polonium (Po)"},"content":{"rendered":"\n

Polonium is a chemical element with the atomic number 84 in the periodic table. It\u2019s a rare and highly radioactive metal. The natural abundance of element 84 in Earth\u2019s crust is only 2 \u00d7 10 \u221210 milligrams per kilogram. <\/span><\/p>\n\n\n\n

Being a member of the chalcogen family of the periodic table, this radioactive metalloid has six valence electrons and six orbitals. Polonium is the most radioactive chemical element in the world with the largest number of isotopes among the chemical elements. Polonium-210 isotope is an exceptionally strong emitter of alpha particles that may lead to bone marrow damage and self-destruction of the cells in our body.<\/span><\/p>\n\n\n\n

<\/div>\n\n\n\n

Chemical and Physical Properties of Polonium<\/span><\/h3>\n\n\n\n
Property<\/strong><\/td>Value<\/strong><\/td><\/tr>
Symbol<\/td>Po<\/td><\/tr>
Name<\/td>Polonium<\/td><\/tr>
Atomic number<\/td>84<\/td><\/tr>
Group<\/td>Metal<\/td><\/tr>
Period<\/td>6 (p-block)<\/td><\/tr>
Color<\/td>A silvery-gray metal<\/td><\/tr>
Physical state<\/td>Solid at 20\u00b0C<\/td><\/tr>
Half-life<\/td>From 0.5 milliseconds to 125.2 years<\/td><\/tr>
Electronegativity<\/td>2<\/td><\/tr>
Density<\/td>9.4 g\/cm\u00b3<\/td><\/tr>
Melting point<\/td>254\u00b0C, 489\u00b0F, 527 K<\/td><\/tr>
Boiling point<\/td>962\u00b0C, 1764\u00b0F, 1235 K<\/td><\/tr>
Van der Waals radius<\/td>0.164 nm<\/td><\/tr>
Ionic radius<\/td>—<\/td><\/tr>
Atomic radius<\/td>1.53 \u00c5<\/td><\/tr>
Covalent radius<\/td>1.46 \u00c5<\/td><\/tr>
Atomic weight<\/td>[209] g.mol-1<\/td><\/tr>
Atomic volume<\/td>22.23 cm\u00b3\/mol<\/td><\/tr>
Isotopes<\/td>42<\/td><\/tr>
Most characteristic isotope<\/td>209Po<\/td><\/tr>
Electronic shell<\/td>[Xe] 4f14 5d10 6s2 6p4<\/td><\/tr>
Valence<\/td>-2,0,2,4,6<\/td><\/tr>
Oxydation states<\/td>(4),2<\/td><\/tr>
Discovery date<\/td>1898<\/td><\/tr>
Discoverers<\/td>Pierre and Marie Curie<\/td><\/tr>
Location of discovery<\/td>France<\/td><\/tr>
Name origin<\/td>Named for Poland, native country of Marie Curie.<\/td><\/tr>
Pronunciation<\/td>peh-LOW-ni-em<\/td><\/tr>
Uses<\/td>Used in industrial equipment to eliminate static electricity<\/td><\/tr>
Description<\/td>Unstable, radioactive member of the halogen<\/a> group.<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

With the periodic table symbol Po, atomic number 84, atomic mass of [209] g.mol<\/span>-1<\/span>, and electron configuration [Xe] 4f<\/span>14<\/span>5d<\/span>10<\/span>6s<\/span>2<\/span>6p<\/span>4<\/span>, polonium is a highly radioactive and reactive silvery-gray semi-metal. It reaches its boiling point at 962\u00b0C, 1764\u00b0F, 1235 K, while the melting point is achieved at 254\u00b0C, 489\u00b0F, 527 K. This member of the chalcogen family of elements has an electronegativity of 2.0 according to Pauling, whereas the atomic radius according to van der Waals is 0.164 nm. <\/span><\/p>\n\n\n\n

Polonium resembles the chemical properties of the elements bismuth<\/a>, selenium, and tellurium. Since its electrical conductivity decreases as its temperature rises, polonium is also classified as a metal substance in the periodic table. In fact, the position of element 84 according to Mendeleev\u2019s classification of elements could make polonium a metal, a metalloid, or a nonmetal.<\/span><\/p>\n\n\n\n

<\/div>\n\n\n\n

How Was Polonium Discovered?<\/span><\/h2>\n\n\n\n

The success story of the two distinguished chemists <\/span>Pierre and Marie Currie<\/span><\/a> did not begin with the discovery of radium. In 1898, they began a series of detailed analyses of mineral ores in an attempt to detect radioactivity in some of them. A naturally occurring ore called <\/span>pitchblende<\/span><\/i> was the first mineral sample in which Pierre and Marie Currie attempted to detect a source of radioactivity which ultimately led these two great scientists to the discovery of polonium.<\/span><\/p>\n\n\n\n

After Marie Sklodowska Curie ambitiously analyzed all known elements of the periodic table, she realized that only two of them give off radiation – uranium<\/a> and thorium<\/a>. As a next step, she decided to analyze the mineral ores containing these two elements. Observing a pitchblende sample obtained from the geological museum, Marie Curie noticed that this uranium ore is more active than uranium. In her opinion, there was clearly a new radioactive chemical element that was even more radioactive than element 92. <\/span><\/p>\n\n\n\n

Sharing her findings with her husband Pierre Curie, she invited him to join her on this new project – an idea that Pierre eagerly accepted. A more detailed analysis of the pitchblende ore informed them that the radioactivity is emitted from the fractions containing bismuth or barium<\/a>. <\/span><\/p>\n\n\n\n

This realization called for an even more detailed look at the atomic structure of the ore Marie and Pierre studied. The continued analysis of the bismuth fractions resulted in a residue that showed even greater activity. This activity was a result of a chemical that turned out to be even 300 times more radioactive than uranium. It was element 84 – polonium. <\/span><\/p>\n\n\n\n

In 1911, Marie Sklodowska Curie became the first woman in the world of science to receive the Nobel Prize in Chemistry for the discovery of the radioactive elements polonium and radium.\u00a0<\/span><\/p>\n\n\n\n

<\/div>\n\n\n\n

How Did Polonium Get Its Name?<\/span><\/h2>\n\n\n\n

Being her first chemical discovery, the Polish scientist Marie Curie named the new element <\/span>polonium (Po)<\/span><\/i> after her home country, Poland.\u00a0<\/span><\/p>\n\n\n\n

<\/div>\n\n\n\n

Where Can You Find Polonium?<\/span><\/h2>\n\n\n\n

Polonium is an extremely rare naturally occurring radioactive element. It can be traced in tiny amounts in the uranium ores. About 100 micrograms (0.0001 grams) of polonium are found in one ton of uranium ore. Typically, this chemical is obtained as a radioactive decay product of uranium, thorium, and actinium<\/a>. Polonium can also be synthesized by bombardment of bismuth-209 (a stable isotope) with neutrons in strictly controlled laboratory conditions. <\/span><\/p>\n\n\n\n

Commercially, polonium is isolated from by-products of the radium extraction process. Radium<\/a> is first isolated from uranium mineral ores with the help of hydrochloric acid, after which the resulting residue solution is heated with hydrogen<\/a> sulfide to precipitate polonium monosulfide (PoS). Pure polonium can also be obtained by electrolytic deposition, by bismuth or lead bombardment with neutrons, or with accelerated charged particles.<\/span><\/p>\n\n\n\n

<\/div>\n\n\n\n

Polonium in Everyday Life<\/span><\/h2>\n\n\n\n

Element 84 can produce neutrons when alloyed with beryllium<\/a>. In this form, polonium is used as a neutron source for alpha radiation. It\u2019s also applied as a heat source and thermoelectric power source in satellites, as well as on the brushes for removing dust from photographic film. <\/span><\/p>\n\n\n\n

Industrially, polonium is used as an agent to eliminate static electricity generated by paper rolling, the spinning of synthetic fibers, or the manufacture of sheet plastics.\u00a0<\/span><\/p>\n\n\n\n

<\/div>\n\n\n\n

How Dangerous Is Polonium?<\/span><\/h2>\n\n\n\n

Since polonium is classified as the most radioactive chemical element in the world, it\u2019s extremely dangerous and may trigger severe health anomalies. <\/span><\/p>\n\n\n\n

The polonium-210 isotope is found in tobacco cigarettes. It\u2019s one of the deadliest known toxins and a <\/span>powerful carcinogen<\/span><\/a>. Namely, only one microgram of this dangerous polonium isotope makes for a lethal dose, i.e. more than enough to kill the average adult. By inhaling it, a smoker (or even a passive smoker) is exposed to direct risk of lung cancer. After a long period of smoking, the smoker\u2019s lungs become lined with a radioactive material and a toxic layer that may lead to various adverse health effects and tumors upon inner irradiation.<\/span><\/p>\n\n\n\n

According to The Centers for Disease Control and Prevention (CDC), cigarettes and tobacco cause more harm to Americans each year than alcohol, suicide, AIDS, homicide, car accidents, and illegal drugs combined. This is due to the combination of many toxic and radioactive substances contained in tobacco cigarettes among which polonium-210 and lead<\/a>-210 are the most dangerous and harmful ones. <\/span><\/p>\n\n\n\n

There are very few real-life cases of direct polonium poisoning, but there are a couple of high-profile ones. A well-known example of inner irradiation with a fatal outcome is the case of <\/span>polonium poisoning<\/span><\/a> of Alexander Litvinenko in London, a former officer of the Russian intelligence. Polonium poisoning was also suspected in the death of the Palestinian leader Yasser Arafat after surprisingly high levels of the <\/span>radioactive polonium-210 isotope<\/span><\/a> were detected on his clothes by a Swiss team of scientists.\u00a0<\/span><\/p>\n\n\n\n

<\/div>\n\n\n\n

Environmental Effects of Polonium<\/span><\/h2>\n\n\n\n

Polonium is an extremely rare, naturally occurring radioactive element. Miniscule amounts of element 84 are mainly found in uranium ores. However, its occurrence in nature is not as hazardous as the plutonium<\/a>-rich waste of the nuclear research laboratories is. <\/span><\/p>\n\n\n\n

The extremely high radioactivity of polonium poses an immense risk upon the environment, as well as upon all living forms in the environment. More specifically, 210Po may contaminate the vegetation, primarily originating from the decay of atmospheric radon<\/a>-222 and absorption from the soil. On the other hand, the relatively short half-life of polonium-210 shortens the toxic exposure to this radioactive form of element 84.\u00a0<\/span><\/p>\n\n\n\n

<\/div>\n\n\n\n

Isotopes of Polonium<\/span><\/h2>\n\n\n\n

There are 42 observed forms of polonium, which makes it a chemical element with the largest number of isotopes in the periodic table. All of the polonium isotopes are extremely radioactive. Polonium-210 is one of its forms that occur naturally, and with a half-life of 138.376 days,<\/span> 210<\/span>Po is the longest living natural isotope of element 84. <\/span><\/p>\n\n\n\n

The extremely toxic and radioactive isotope polonium-210 is an alpha emitter with a half-life of 138.4 days. <\/span>210<\/span>Po isotope is typically manmade, i.e. produced synthetically through neutron bombardment of <\/span>209<\/span>Bi in a nuclear reactor.<\/span><\/p>\n\n\n\n

Among the radioisotopes, polonium-209 is the longest living synthetically produced form of polonium, with a half-life of 125.2 years. The polonium-20 and polonium-209 isotopes can be created by a proton bombardment of bismuth in a cyclotron. <\/span><\/p>\n\n\n\n

Main Isotopes of Polonium<\/span><\/i> <\/span><\/p>\n\n\n\n

Iso\u00adtope<\/b><\/td> Decay<\/b><\/td> <\/tr>
\u00a0<\/td> abun\u00addance<\/b><\/td> half-life <\/b>(<\/span>t<\/span><\/i>1\/2)<\/span><\/td> mode<\/b><\/td> pro\u00adduct<\/b><\/td> \u00a0<\/td> <\/tr>
208Po<\/b><\/td> syn<\/span><\/td> 2.898 y<\/span><\/td> \u03b1<\/span><\/td> 204Pb<\/span><\/td> \u00a0<\/td> <\/tr>
\u03b2+<\/span><\/td> 208Bi<\/span><\/td> \u00a0<\/td> <\/tr>
209Po<\/b><\/td> syn<\/span><\/td> 125.2 y[1]<\/span><\/td> \u03b1<\/span><\/td> 205Pb<\/span><\/td> \u00a0<\/td> <\/tr>
\u03b2+<\/span><\/td> 209Bi<\/span><\/td> \u00a0<\/td> <\/tr>
210Po<\/b><\/td> trace<\/span><\/td> 138.376 d<\/span><\/td> \u03b1<\/span><\/td> 206Pb<\/span><\/td> \u00a0<\/td> <\/tr> <\/tbody> <\/table>

Source: Wikipedia<\/span><\/p><\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

<\/div>\n\n\n\n

List of Polonium Compounds <\/span><\/h2>\n\n\n\n

Almost all of the polonium compounds have been prepared for scientific research. No compounds contain element 84 with practical everyday use. The commonly exhibited oxidation states of polonium are +4 and +2.\u00a0<\/span><\/p>\n\n\n\n