Polonium (Po)
metalloidSolid
प्रमाणित अणुभार
[209]इलेक्ट्रॉन संरूपण
[Xe] 6s2 4f14 5d10 6p4द्रवणांक
253.85 °Cउत्कलनांक
961.85 °Cघनता
9320 kg/m³ऑक्सिडीकरण अवस्था
−2, +2, +4, +5, +6विद्युतऋणता (पॉलिंग)
2आयनीकरण ऊर्जा (पहिली)
8.41807 eVशोधाचे वर्ष
1898अणुत्रिज्या
190 pmतपशील
Polonium is a very rare, highly radioactive chalcogen below tellurium in group 16. It occurs naturally only in minute amounts as part of uranium and thorium decay chains, chiefly through isotopes such as ²¹⁰Po. Its chemistry combines metallic character with chalcogen behavior, and its significance comes mainly from intense alpha radioactivity rather than from ordinary materials use.
Polonium-210 is a low-melting, fairly volatile metal, 50% of which is vaporized in air in 45 hours at 55°C. It is an alpha emitter with a half-life of 138.39 days. A milligram emits as many alpha particles as 5 g of radium.
The energy released by its decay is so large (140W/g) that a capsule containing about half a gram reaches a temperature above 500C. The capsule also presents a contact gamma-ray dose rate of 0.012 Gy/h. A few curies (1 curie = 3.7 x 1010Bq) of polonium exhibit a blue glow, caused by excitation of the surrounding gas.
Polonium is readily dissolved in dilute acids, but is only slightly soluble in alkali. Polonium salts of organic acids char rapidly; halide amines are reduced to the metal.
Polonium was discovered by Marie Sklodowska Curie, a Polish chemist, in 1898. She obtained polonium from pitchblende, a material that contains uranium, after noticing that unrefined pitchblende was more radioactive than the uranium that was separated from it. She reasoned that pitchblende must contain at least one other radioactive element. Curie needed to refine several tons of pitchblende in order to obtain tiny amounts of polonium and radium, another radioactive element discovered by Curie. One ton of uranium ore contains only about 100 micrograms (0.0001 grams) of polonium. Due to its scarcity, polonium is usually produced by bombarding bismuth-209 with neutrons in a nuclear reactor. This forms bismuth-210, which has a half-life of 5 days. Bismuth-210 decays into polonium-210 through beta decay. Milligram amounts of polonium-210 have been produced by this method.
Polonium-210 is a very strong emitter of alpha particles. A single gram of polonium-210 creates 140 Watts of heat energy and is being considered as a lightweight heat source for thermoelectric power for spacecraft. Polonium-210 has a half-life of 138.39 days.
Polonium's most stable isotope, polonium-209, has a half-life of 102 years. It decays into lead-205 through alpha decay. Polonium-209 is available from Oak Ridge National Laboratory at the cost of about $3200 per microcurie.
Named after Poland, native country of Madam Curie. Polonium, also called Radium F, was the first element discovered by Curie in 1898 while seeking the cause of radioactivity of pitchblend from Joachimsthal, Bohemia. The electroscope showed it separating with bismuth.
Macroscopic polonium is difficult to handle and observe because it self-heats and rapidly accumulates radiation damage. The pure element is reported as a silvery metal; two solid allotropes are known near ordinary temperatures, including a simple cubic form unusual among elements.
Polonium has no broad commercial use. Historically, ²¹⁰Po was used in static eliminators and neutron sources when mixed with beryllium, where alpha particles drive neutron emission. Such uses have largely been replaced or tightly restricted because of radiological risk and regulatory burden. Small quantities remain relevant for calibration, specialized research, and legacy sealed-source applications.
Polonium can be used to eliminate static electricity in machinery that is caused by processes such as the rolling of paper, wire or sheet metal, although other materials which emit beta particles are more commonly used for this purpose. Polonium is also used in brushes for removing dust from photographic films, although the polonium must be carefully sealed to protect the user from contamination. Polonium is also combined with beryllium to form neutron sources.
Because almost all alpha radiation is stopped within the solid source and its container, giving up its energy, polonium has attracted attention for uses as a lightweight heat source for thermoelectric power in space satellites.
Polonium can be mixed or alloyed with beryllium to provide a source of neutrons. The element has been used in devices for eliminating static charges in textile mills, etc.; however, beta sources are both more commonly used and less dangerous. It is also used on brushes for removing dust from photographic films. The polonium for these is carefully sealed and controlled, minimizing hazards to the user.
Isotopes in Industry
210Po (with a half-life of 138 days) is used as static eliminator to remove static electricity in machinery. This is useful in machinery that produces electricity easily, for example, via rolling paper, manufacturing sheet plastics, and spinning synthetic fibers, which all readily produce static [75] J. Peterson, M. McDonell, L. Haroun, F. Monette, R. D. Hildebrand, A. Taboas. Radiological and Chemical Fact Sheets to Support Health Risk Analyses for Contaminated Areas, Prepared by Argonne National Laboratory Environmental Science Division in collaboration with U.S. Department of Energy, Richland Operations Office and Chicago Operations Office (2014), Feb. 22; http://www.remm.nlm.gov/ANL_ContaminantFactSheets_All_070418.pdf., [563] United States Nuclear Regulatory Commission. Backgrounder on Polonium-210, United States Nuclear Regulatory Commission (2017), April 8; http://www.nrc.gov/reading-rm/doc-collections/fact-sheets/polonium.html.. 210Po can also make use of its static eliminating properties when used in brushes that function to clean camera lenses and photographic films (Fig. IUPAC.84.1) [75] J. Peterson, M. McDonell, L. Haroun, F. Monette, R. D. Hildebrand, A. Taboas. Radiological and Chemical Fact Sheets to Support Health Risk Analyses for Contaminated Areas, Prepared by Argonne National Laboratory Environmental Science Division in collaboration with U.S. Department of Energy, Richland Operations Office and Chicago Operations Office (2014), Feb. 22; http://www.remm.nlm.gov/ANL_ContaminantFactSheets_All_070418.pdf.. 210Po has been used to manufacture atomic weapons. When combined with beryllium, polonium can act as a neutron-producing initiator. However, because of its short half-life, 210Po is no longer used in this manner [75] J. Peterson, M. McDonell, L. Haroun, F. Monette, R. D. Hildebrand, A. Taboas. Radiological and Chemical Fact Sheets to Support Health Risk Analyses for Contaminated Areas, Prepared by Argonne National Laboratory Environmental Science Division in collaboration with U.S. Department of Energy, Richland Operations Office and Chicago Operations Office (2014), Feb. 22; http://www.remm.nlm.gov/ANL_ContaminantFactSheets_All_070418.pdf..
Polonium chemistry is best known for oxidation states −2, +2, +4, and +6, with +4 often prominent in aqueous and halide chemistry. Representative compounds include polonium dioxide, PoO₂, polonium tetrachloride, PoCl₄, and polonium hydride, H₂Po, an unstable hydrogen chalcogenide. Polonides are formed with electropositive metals, but many compounds are hard to study because radiolysis and self-heating alter samples.
See more information at the Polonium compound page.
Polonium is an extreme internal radiological hazard, especially ²¹⁰Po, an alpha emitter. Alpha particles are stopped by skin or thin barriers, but inhaled, ingested, or wound-introduced material can deliver severe localized doses. The element is also chemically toxic, though radiation dominates most risk assessments. Work requires sealed containment, contamination control, and isotope-specific monitoring.
Polonium-210 is very dangerous to handle in even milligram or microgram amounts, and special equipment and strict control is necessary. Damage arises from the complete absorption of the energy of the alpha particle into tissue.
Natural polonium is generated continuously in uranium and thorium decay series and is present at trace levels in rocks, soils, seawater, and the atmosphere. ²¹⁰Po can be transferred through air, water, and food webs, often following particles and sulfur- or selenium-like chemical pathways. It decays rather than persisting indefinitely, but local concentrations can matter in biological and radiological studies.
Polonium is not a traded bulk commodity. Usable ²¹⁰Po is produced in specialized nuclear facilities, commonly by neutron irradiation of bismuth to form ²¹⁰Bi, which decays to ²¹⁰Po, followed by radiochemical separation. Supply is limited by short half-life, licensing, security, and handling costs rather than ore availability. Substitution by less hazardous technologies has sharply reduced routine demand, so production is small and purpose-specific.
Polonium is a very rare natural element. Uranium ores contain only about 100 micrograms of the element per ton. Its abundance is only about 0.2% of that of radium.
In 1934, scientists discovered that when they bombarded natural bismuth (209Bi) with neutrons, 210Bi, the parent of polonium, was obtained. Milligram amounts of polonium may now be prepared this way, by using the high neutron fluxes of nuclear reactors.
Polonium has no stable isotopes, so primordial polonium has long since decayed. In space it is expected only as a transient product of radioactive decay chains or nucleosynthesis pathways involving heavy nuclei. Any detectable amount in planetary materials reflects recent generation from longer-lived actinides, not independent cosmic abundance.
- ²¹⁰Po has a half-life of about 138 days, which strongly limits storage and distribution.
- Polonium was identified by Marie and Pierre Curie in pitchblende residues in 1898.
- The name honored Poland, which was not then an independent state.
- Elemental polonium can become warm from its own alpha-decay heat.
- A polonium-beryllium source produces neutrons without requiring a reactor during use.
- Polonium's simple cubic alpha allotrope is rare among elemental crystal structures.
प्रतिमा
गुणधर्म
भौतिक
- अणुत्रिज्या (अनुभवाधारित)
- 190 pm सर्व घटकांच्या अणुत्रिज्या (अनुभवाधारित) ची तुलना करा →
- सहसंयुजी त्रिज्या
- 140 pm सर्व घटकांच्या सहसंयुजी त्रिज्या ची तुलना करा →
- व्हॅन डर वाल्स त्रिज्या
- 197 pm सर्व घटकांच्या व्हॅन डर वाल्स त्रिज्या ची तुलना करा →
- घनता
- 9320 kg/m³ सर्व घटकांच्या घनता ची तुलना करा →
- मोलर आयतन
- 0.0227 L/mol
- STP येथे अवस्था
- घन सर्व घटकांच्या STP येथे अवस्था ची तुलना करा →
- द्रवणांक
- 253.85 °C सर्व घटकांच्या द्रवणांक ची तुलना करा →
- उत्कलनांक
- 961.85 °C सर्व घटकांच्या उत्कलनांक ची तुलना करा →
- स्फटिक संरचना
- साधी घनीय सर्व घटकांच्या स्फटिक संरचना ची तुलना करा →
रासायनिक
- विद्युतऋणता (पॉलिंग)
- 2 सर्व घटकांच्या विद्युतऋणता (पॉलिंग) ची तुलना करा →
- विद्युतऋणता (ॲलन)
- 2.19
- इलेक्ट्रॉन आसक्ती
- 1.9 eV
- आयनीकरण ऊर्जा (पहिली)
- 8.41807 eV सर्व घटकांच्या आयनीकरण ऊर्जा (पहिली) ची तुलना करा →
- आयनीकरण ऊर्जा (दुसरी)
- 19.300066 eV सर्व घटकांच्या आयनीकरण ऊर्जा (दुसरी) ची तुलना करा →
- आयनीकरण ऊर्जा (तिसरी)
- 27.300094 eV सर्व घटकांच्या आयनीकरण ऊर्जा (तिसरी) ची तुलना करा →
- आयनीकरण ऊर्जा (चौथी)
- 36.000124 eV सर्व घटकांच्या आयनीकरण ऊर्जा (चौथी) ची तुलना करा →
- आयनीकरण ऊर्जा (पाचवी)
- 57.000196 eV सर्व घटकांच्या आयनीकरण ऊर्जा (पाचवी) ची तुलना करा →
- ऑक्सिडीकरण अवस्था
- −2, +2, +4, +5, +6 सर्व घटकांच्या ऑक्सिडीकरण अवस्था ची तुलना करा →
- संयुजा इलेक्ट्रॉन
- 6 सर्व घटकांच्या संयुजा इलेक्ट्रॉन ची तुलना करा →
- इलेक्ट्रॉन संरूपण
- [Xe] 6s2 4f14 5d10 6p4
उष्मागतिक
- द्रवण उष्मा
- 0.13473597 eV सर्व घटकांच्या द्रवण उष्मा ची तुलना करा →
- बाष्पीभवन उष्मा
- 1.057159 eV सर्व घटकांच्या बाष्पीभवन उष्मा ची तुलना करा →
- संप्लवन उष्मा
- 1.824118 eV
- अणूकरण उष्मा
- 1.824118 eV
केंद्रकीय
- प्रोटॉन
- 84 सर्व घटकांच्या प्रोटॉन ची तुलना करा →
- न्यूट्रॉन
- 125 सर्व घटकांच्या न्यूट्रॉन ची तुलना करा →
- ज्ञात समस्थानिके
- 42 सर्व घटकांच्या ज्ञात समस्थानिके ची तुलना करा →
- स्थिर समस्थानिके
- 0 सर्व घटकांच्या स्थिर समस्थानिके ची तुलना करा →
- वस्तुमानांक (सर्वाधिक स्थिर)
- 209
- सर्वाधिक स्थिर समस्थानिक
- Po-209
- शोधाचे वर्ष
- 1898
विपुलता
- विपुलता (पृथ्वीचे कवच)
- 2e-10 mg/kg सर्व घटकांच्या विपुलता (पृथ्वीचे कवच) ची तुलना करा →
- विपुलता (महासागर)
- 1.5 × 10−14 mg/L सर्व घटकांच्या विपुलता (महासागर) ची तुलना करा →
स्फटिक संरचना
- जालक स्थिरांक a
- 335 pm
इलेक्ट्रॉन संरचना
- प्रत्येक कवचातील इलेक्ट्रॉन
- 2, 8, 18, 32, 18, 6 सर्व घटकांच्या प्रत्येक कवचातील इलेक्ट्रॉन ची तुलना करा →
ओळखचिन्हे
- CAS क्रमांक
- 7440-08-6 सर्व घटकांच्या CAS क्रमांक ची तुलना करा →
- टर्म चिन्ह
- 3P2
- InChI
- InChI=1S/Po
- InChI की
- HZEBHPIOVYHPMT-UHFFFAOYSA-N
इलेक्ट्रॉन संरूपण मोजलेले
Po: 4f¹⁴ 5d¹⁰ 6s² 6p⁴[Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁴1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶ 4f¹⁴ 5d¹⁰ 6s² 6p⁴अणुप्रतिमान
समस्थानिकांमुळे न्यूट्रॉन संख्या, वस्तुमान आणि स्थैर्य बदलते — विद्युतदृष्ट्या उदासीन अणूचे इलेक्ट्रॉन संरूपण बदलत नाही.
योजनात्मक अणुप्रतिमान, प्रमाणानुसार नाही.
अणूची विशिष्ट ओळख
उत्सर्जन / शोषण वर्णपट
समस्थानिक वितरण
स्थिर समस्थानिके नाहीत.
| वस्तुमानांक | अणुवस्तुमान (u) | नैसर्गिक विपुलता | अर्धायुष्य |
|---|---|---|---|
| 211 किरणोत्सारी | २१०.९८६६५३६ ± ०.०००००१४ | उपलब्ध नाही | 516 ms |
| 193 किरणोत्सारी | १९२.९९१०२६ ± ०.००००३७ | उपलब्ध नाही | 399 ms |
| 194 किरणोत्सारी | १९३.९८८१८६ ± ०.००००१४ | उपलब्ध नाही | 392 ms |
| 212 किरणोत्सारी | २११.९८८८६८४ ± ०.०००००१३ | उपलब्ध नाही | 294.4 ns |
| 188 किरणोत्सारी | १८७.९९९४१६ ± ०.००००२१ | उपलब्ध नाही | 270 us |
अवस्था / स्थिती
कारण: द्रवणांकापेक्षा (253.85 °C) 228.9 °C कमी
योजनात्मक, प्रमाणानुसार नाही
अवस्थांतर बिंदू
अवस्थांतर ऊर्जा
द्रवणांकावर 1 mol वितळवण्यासाठी आवश्यक ऊर्जा
उत्कलनांकावर 1 mol चे बाष्पीभवन करण्यासाठी आवश्यक ऊर्जा
संप्लवनांकावर 1 mol चे संप्लवन करण्यासाठी आवश्यक ऊर्जा
घनता
प्रमाणित परिस्थितीत
प्रमाणित परिस्थितीत
अणुवर्णपट
84 पैकी 10 दाखवले आहेत. आयनाच्या विद्युतभारानुसार चढत्या क्रमाने मांडलेले.
वर्णरेषांचा संग्रह ?
| आयन | विद्युतभार | एकूण वर्णरेषा | संक्रमण संभाव्यता | पातळ्यांची नामांकने |
|---|---|---|---|---|
| Po I | 0 | 37 | 0 | 4 |
ऊर्जा पातळ्यांचा संग्रह ?
| आयन | विद्युतभार | पातळ्या |
|---|---|---|
| Po I | 0 | 33 |
| Po II | +1 | 2 |
| Po III | +2 | 2 |
| Po IV | +3 | 2 |
| Po V | +4 | 2 |
| Po VI | +5 | 2 |
| Po VII | +6 | 2 |
| Po VIII | +7 | 2 |
| Po IX | +8 | 2 |
| Po X | +9 | 2 |
आयनिक त्रिज्या
| विद्युतभार | समन्वय | प्रचक्रण | त्रिज्या |
|---|---|---|---|
| +4 | 6 | उपलब्ध नाही | 94 pm |
| +4 | 8 | उपलब्ध नाही | 108 pm |
| +6 | 6 | उपलब्ध नाही | 67 pm |
संयुगे
समस्थानिके (5)
Twenty five isotopes of polonium are known, with atomic masses ranging from 194 to 218. Polonium-210 is the most readily available. Isotopes of mass 209 (half-life 103 years) and mass 208 (half-life 2.9 years) can be prepared by alpha, proton, or deuteron bombardment of lead or bismuth in a cyclotron, but these are expensive to produce.
| वस्तुमानांक | अणुवस्तुमान (u) | नैसर्गिक विपुलता | अर्धायुष्य | क्षय प्रकार | |
|---|---|---|---|---|---|
| 211 किरणोत्सारी | २१०.९८६६५३६ ± ०.०००००१४ | उपलब्ध नाही | 516 ms | α =100% | |
| 193 किरणोत्सारी | १९२.९९१०२६ ± ०.००००३७ | उपलब्ध नाही | 399 ms | α ≈100%β+ ? | |
| 194 किरणोत्सारी | १९३.९८८१८६ ± ०.००००१४ | उपलब्ध नाही | 392 ms | α ≈100%β+ ? | |
| 212 किरणोत्सारी | २११.९८८८६८४ ± ०.०००००१३ | उपलब्ध नाही | 294.4 ns | α =100% | |
| 188 किरणोत्सारी | १८७.९९९४१६ ± ०.००००२१ | उपलब्ध नाही | 270 us | α ≈100%β+ ? |
विस्तारित गुणधर्म
सहसंयुजी त्रिज्या (विस्तारित)
- सहसंयुजी त्रिज्या (प्युक्को)
- 145 pm
- सहसंयुजी त्रिज्या (प्युक्को, दुहेरी बंध)
- 135 pm
- सहसंयुजी त्रिज्या (प्युक्को, तिहेरी बंध)
- 129 pm
व्हॅन डर वाल्स त्रिज्या
- Truhlar
- 197 pm
- UFF
- 470.9 pm
- MM3
- 259 pm
अणुत्रिज्या आणि धात्विक त्रिज्या
- अणुत्रिज्या (राह्म)
- 250 pm
क्रमांकन मापनपट्ट्या
- Mendeleev
- 103
- Pettifor
- 91
- Glawe
- 93
विद्युतऋणता मापनपट्ट्या
- Ghosh
- 0
- Gunnarsson–Lundqvist
- 6
- Robles–Bartolotti
- 4
ध्रुवणक्षमता आणि अपस्करण
- द्विध्रुव ध्रुवणक्षमता
- 44 a.u.
- द्विध्रुव ध्रुवणक्षमता (अनिश्चितता)
- 4 a.u.
- C₆ (Gould–Bučko)
- 424 Ha·Bohr6
अवस्थांतरे आणि अपरूपे
| द्रवणांक | 527.15 K |
| उत्कलनांक | 1235.15 K |
ऑक्सिडीकरण अवस्थांचे वर्ग
प्रगत संदर्भ माहिती
परिरक्षण स्थिरांक (15)
| n | कक्षिका | σ |
|---|---|---|
| 1 | s | 1.6232 |
| 2 | p | 4.5428 |
| 2 | s | 22.0782 |
| 3 | d | 13.428 |
| 3 | p | 23.2851 |
| 3 | s | 24.3813 |
| 4 | d | 36.3328 |
| 4 | f | 37.8416 |
| 4 | p | 36.3328 |
| 4 | s | 35.4784 |
स्फटिक त्रिज्यांचा तपशील (3)
| विद्युतभार | CN | प्रचक्रण | rcrystal (pm) | उत्पत्ती |
|---|---|---|---|---|
| 4 | VI | 108 | from r^3 vs V plots, | |
| 4 | VIII | 122 | from r^3 vs V plots, | |
| 6 | VI | 81 | Ahrens (1952) ionic radius, |
समस्थानिक क्षय प्रकार (71)
| समस्थानिक | मोड | तीव्रता |
|---|---|---|
| 186 | A | 100% |
| 186 | p | — |
| 187 | A | 100% |
| 187 | B+ | — |
| 188 | A | 100% |
| 188 | B+ | — |
| 189 | A | 100% |
| 189 | B+ | — |
| 190 | A | 100% |
| 190 | B+ | — |
क्ष-किरण प्रकीर्णन गुणक (516)
| ऊर्जा (eV) | f₁ | f₂ |
|---|---|---|
| 10 | — | 4.92763 |
| 10.1617 | — | 4.95784 |
| 10.3261 | — | 4.98823 |
| 10.4931 | — | 5.01881 |
| 10.6628 | — | 5.04957 |
| 10.8353 | — | 5.10634 |
| 11.0106 | — | 5.17368 |
| 11.1886 | — | 5.24191 |
| 11.3696 | — | 5.31104 |
| 11.5535 | — | 5.38108 |
अतिरिक्त माहिती
Estimated Crustal Abundance
The estimated element abundance in the earth's crust.
2×10-10 milligrams per kilogram
संदर्भ (1)
- [5] Polonium https://education.jlab.org/itselemental/ele084.html
Estimated Oceanic Abundance
The estimated element abundance in the earth's oceans.
1.5×10-14 milligrams per liter
संदर्भ (1)
- [5] Polonium https://education.jlab.org/itselemental/ele084.html
Sources
Sources of this element.
Polonium is a very rare natural element. Uranium ores contain only about 100 micrograms of the element per ton. Its abundance is only about 0.2% of that of radium.
In 1934, scientists discovered that when they bombarded natural bismuth (209Bi) with neutrons, 210Bi, the parent of polonium, was obtained. Milligram amounts of polonium may now be prepared this way, by using the high neutron fluxes of nuclear reactors.
संदर्भ (1)
- [6] Polonium https://periodic.lanl.gov/84.shtml
संदर्भ
(9)
Data deposited in or computed by PubChem
The half-life and atomic mass data was provided by the Atomic Mass Data Center at the International Atomic Energy Agency.
Element data are cited from the Atomic weights of the elements (an IUPAC Technical Report). The IUPAC periodic table of elements can be found at https://iupac.org/what-we-do/periodic-table-of-elements/. Additional information can be found within IUPAC publication doi:10.1515/pac-2015-0703 Copyright © 2020 International Union of Pure and Applied Chemistry.
The information are cited from Pure Appl. Chem. 2018; 90(12): 1833-2092, https://doi.org/10.1515/pac-2015-0703.
Thomas Jefferson National Accelerator Facility (Jefferson Lab) is one of 17 national laboratories funded by the U.S. Department of Energy. The lab's primary mission is to conduct basic research of the atom's nucleus using the lab's unique particle accelerator, known as the Continuous Electron Beam Accelerator Facility (CEBAF). For more information visit https://www.jlab.org/
The periodic table at the LANL (Los Alamos National Laboratory) contains basic element information together with the history, source, properties, use, handling and more. The provenance data may be found from the link under the source name.
The periodic table contains NIST's critically-evaluated data on atomic properties of the elements. The provenance data that include data for atomic spectroscopy, X-ray and gamma ray, radiation dosimetry, nuclear physics, and condensed matter physics may be found from the link under the source name. Ref: https://www.nist.gov/pml/atomic-spectra-database
This section provides all form of data related to element Polonium.
The element property data was retrieved from publications.