Astatine (At)
halogenSolid
प्रमाणित अणुभार
[210]इलेक्ट्रॉन संरूपण
[Xe] 6s2 4f14 5d10 6p5द्रवणांक
301.85 °Cउत्कलनांक
उपलब्ध नाहीघनता
7000 kg/m³ऑक्सिडीकरण अवस्था
−1, +1, +3, +5, +7विद्युतऋणता (पॉलिंग)
2.2आयनीकरण ऊर्जा (पहिली)
9.31751 eVशोधाचे वर्ष
1940अणुत्रिज्या
उपलब्ध नाहीतपशील
Astatine is a very rare, highly radioactive halogen below iodine in group 17. All of its isotopes are unstable, and only minute amounts occur naturally as short-lived products in uranium and thorium decay chains. Its chemistry is partly experimental and partly inferred from periodic trends, because usable quantities are extremely small. Astatine shows both halogen-like behavior and unusually metallic character for a halogen.
The "time of flight" mass spectrometer has been used to confirm that this highly radioactive halogen behaves chemically very much like other halogens, particularly iodine. Astatine is said to be more metallic than iodine, and, like iodine, it probably accumulates in the thyroid gland. Workers at the Brookhaven National Laboratory have recently used reactive scattering in crossed molecular beams to identify and measure elementary reactions involving astatine.
Astatine was produced by Dale R. Carson, K.R. MacKenzie and Emilio Segrè by bombarding an isotope of bismuth, bismuth-209, with alpha particles that had been accelerated in a device called a cyclotron. This created astatine-211 and two free neutrons. This work was conducted at the University of California in 1940. Small amounts of astatine exist in nature as a result of the decay of uranium and thorium, although the total amount of astatine in the earth's crust at any particular time is less than 30 grams. Due to its scarcity, astatine is produced when it is needed. A total of 0.05 micrograms (0.00000005 grams) of astatine have been produced to date.
Astatine's most stable isotope, astatine-210, has a half-life of 8.1 hours. It decays into bismuth-206 through alpha decay or into polonium-210 through electron capture.
From the Greek astatos meaning unstable. Synthesized in 1940 by D.R. Corson, K.R. MacKenzie, and E. Segre at the University of California by bombarding bismuth with alpha particles. The longest-lived isotopes, with naturally occurring uranium and thorium isotopes, and traces of 217At are equilibrium with 233U and 239Np resulting from integration of thorium and uranium with naturally produced neutrons. The total amount of astatine present in the earth's crust, however, is less than 1 oz.
The bulk appearance of astatine has not been directly observed in a macroscopic sample. It is usually handled atom-by-atom or in ultratrace solution. A dark solid, possibly with metallic character, is predicted from periodic trends but is not an experimentally established description.
Astatine has no commercial use as an element. Its main practical interest is in nuclear medicine research, especially ²¹¹At for targeted alpha-particle therapy studies. This isotope can be attached to carrier molecules that seek selected biological targets, but its short half-life and difficult production limit routine use. Other uses are confined to radiochemical research, tracer-scale studies of heavy halogen chemistry, and isotope-production development.
Due to the small amounts produced and its short half-life, there are currently no uses for astatine outside of basic scientific research.
Isotopes in Medicine
211At (with a half-life of 7.2 h) is known to accumulate in the thyroid and occasionally is the preferred treatment for hyperthyroidism and thyroid cancer because the particles emitted from 211At provide more energy than radiolabeled iodine, the other treatment method (Fig. IUPAC.85.1). However, astatine has shown a tendency to induce tumors, so its use is limited [565] L. M. Cobb, A. Harrison, N. E. Dudley, T. E. F. Carr, J. A. Humphreys. Radiother. Oncol.13, 203 (1988).. The 211At-labeled di-carborane (cluster of boron, carbon, and hydrogen atoms) ligand known as the Venus Flytrap Cluster (VFC) has been used as a robust pharmaceutical in radiotherapy treatment [566] J. T. Gullon. “The preparation of metallocarborane and iodinated carborane amino acid analogues for molecular imaging and therapy”, S. dissertation, Dept. of Chemistry, McMaster University, Hamilton, Ontario, Canada (2010). http://hdl.handle.net/11375/9362..
Astatine chemistry is dominated by tracer-scale studies, so many compounds are identified by behavior rather than by isolating bulk material. It can form astatide ions, At⁻, and interhalogen or pseudohalogen-like species. Oxidation states from −1 to positive states such as +1, +3, +5, and possibly +7 are discussed, depending strongly on medium and ligand. Species such as hydrogen astatide, HAt, and astatine monoiodide, AtI, are known or inferred in small-scale studies. Organ astatine compounds with carbon–astatine bonds are important in radiolabeling research.
See more information at the Astatine compound page.
Astatine hazards are dominated by radioactivity, not ordinary chemical toxicity data. Isotope-specific half-lives and decay modes matter; ²¹¹At is an alpha emitter, while other isotopes may have different radiation signatures. Even tiny masses can require shielding, containment, remote handling, and contamination control. Chemical toxicity is poorly characterized because quantities are far below conventional toxicological testing levels.
Natural astatine exists only transiently in trace quantities within radioactive decay chains, mainly associated with uranium- and thorium-bearing minerals. Its atoms decay before they can accumulate or take part in a substantial geochemical cycle. Environmental behavior is therefore inferred from halogen chemistry and radiochemical experiments rather than observed at bulk scale. Releases of artificial astatine would be controlled primarily by its short-lived radioactivity and chemical form.
Astatine has no commodity market and is not mined as a product. Research quantities, especially ²¹¹At, are produced in particle accelerators, commonly by bombarding bismuth targets and then rapidly separating the product. Supply is constrained by isotope half-life, specialized cyclotron access, target processing, transport time, and radiochemical infrastructure. Recycling is not meaningful in the usual industrial sense because the isotopes decay quickly and are used in tracer or medical-research amounts.
Does not occur in nature. Similar to iodine. Produced by bombarding bismuth with alpha particles.
Astatine is not a significant cosmic reservoir element. Any astatine formed in stellar nucleosynthesis or radioactive decay is short-lived on geological and astronomical timescales, so it does not persist in detectable bulk abundance. In planetary materials it can appear only as a temporary daughter product of heavier radioactive nuclides.
- Astatine is usually studied in quantities far below a visible speck.
- The longest-lived known astatine isotopes still have half-lives of only hours.
- The name comes from a Greek word meaning unstable.
- ²¹¹At is valued in research because alpha particles travel only short distances in tissue.
- Astatine can behave less like a simple halogen than iodine does, especially in positive oxidation states.
प्रतिमा
गुणधर्म
भौतिक
- सहसंयुजी त्रिज्या
- 150 pm सर्व घटकांच्या सहसंयुजी त्रिज्या ची तुलना करा →
- व्हॅन डर वाल्स त्रिज्या
- 202 pm सर्व घटकांच्या व्हॅन डर वाल्स त्रिज्या ची तुलना करा →
- घनता
- 7000 kg/m³ सर्व घटकांच्या घनता ची तुलना करा →
- STP येथे अवस्था
- घन सर्व घटकांच्या STP येथे अवस्था ची तुलना करा →
- द्रवणांक
- 301.85 °C सर्व घटकांच्या द्रवणांक ची तुलना करा →
रासायनिक
- विद्युतऋणता (पॉलिंग)
- 2.2 सर्व घटकांच्या विद्युतऋणता (पॉलिंग) ची तुलना करा →
- विद्युतऋणता (ॲलन)
- 2.39
- इलेक्ट्रॉन आसक्ती
- 2.391 eV
- आयनीकरण ऊर्जा (पहिली)
- 9.31751 eV सर्व घटकांच्या आयनीकरण ऊर्जा (पहिली) ची तुलना करा →
- आयनीकरण ऊर्जा (दुसरी)
- 17.880062 eV सर्व घटकांच्या आयनीकरण ऊर्जा (दुसरी) ची तुलना करा →
- आयनीकरण ऊर्जा (तिसरी)
- 26.580091 eV सर्व घटकांच्या आयनीकरण ऊर्जा (तिसरी) ची तुलना करा →
- आयनीकरण ऊर्जा (चौथी)
- 39.650136 eV सर्व घटकांच्या आयनीकरण ऊर्जा (चौथी) ची तुलना करा →
- आयनीकरण ऊर्जा (पाचवी)
- 50.390173 eV सर्व घटकांच्या आयनीकरण ऊर्जा (पाचवी) ची तुलना करा →
- ऑक्सिडीकरण अवस्था
- −1, +1, +3, +5, +7 सर्व घटकांच्या ऑक्सिडीकरण अवस्था ची तुलना करा →
- संयुजा इलेक्ट्रॉन
- 7 सर्व घटकांच्या संयुजा इलेक्ट्रॉन ची तुलना करा →
- इलेक्ट्रॉन संरूपण
- [Xe] 6s2 4f14 5d10 6p5
उष्मागतिक
- द्रवण उष्मा
- 0.06218583 eV सर्व घटकांच्या द्रवण उष्मा ची तुलना करा →
- बाष्पीभवन उष्मा
- 0.41457221 eV सर्व घटकांच्या बाष्पीभवन उष्मा ची तुलना करा →
- संप्लवन उष्मा
- 1.554646 eV
- अणूकरण उष्मा
- 1.554646 eV
केंद्रकीय
- प्रोटॉन
- 85 सर्व घटकांच्या प्रोटॉन ची तुलना करा →
- न्यूट्रॉन
- 125 सर्व घटकांच्या न्यूट्रॉन ची तुलना करा →
- ज्ञात समस्थानिके
- 39 सर्व घटकांच्या ज्ञात समस्थानिके ची तुलना करा →
- स्थिर समस्थानिके
- 0 सर्व घटकांच्या स्थिर समस्थानिके ची तुलना करा →
- वस्तुमानांक (सर्वाधिक स्थिर)
- 210
- सर्वाधिक स्थिर समस्थानिक
- At-210
- शोधाचे वर्ष
- 1940
विपुलता
उपलब्ध नाही
स्फटिक संरचना
उपलब्ध नाही
इलेक्ट्रॉन संरचना
- प्रत्येक कवचातील इलेक्ट्रॉन
- 2, 8, 18, 32, 18, 7 सर्व घटकांच्या प्रत्येक कवचातील इलेक्ट्रॉन ची तुलना करा →
ओळखचिन्हे
- CAS क्रमांक
- 7440-68-8 सर्व घटकांच्या CAS क्रमांक ची तुलना करा →
- टर्म चिन्ह
- 2P°3/2
- InChI
- InChI=1S/At
- InChI की
- RYXHOMYVWAEKHL-UHFFFAOYSA-N
इलेक्ट्रॉन संरूपण मोजलेले
At: 4f¹⁴ 5d¹⁰ 6s² 6p⁵[Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁵1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶ 4f¹⁴ 5d¹⁰ 6s² 6p⁵अणुप्रतिमान
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 |
|---|---|---|---|
| 214 किरणोत्सारी | २१३.९९६३७२१ ± ०.०००००४६ | उपलब्ध नाही | 558 ns |
| 197 किरणोत्सारी | १९६.९९३१८९ ± ०.००००५५ | उपलब्ध नाही | 388.2 ms |
| 196 किरणोत्सारी | १९५.९९५८ ± ०.००००३३ | उपलब्ध नाही | 377 ms |
| 212 किरणोत्सारी | २११.९९०७३७७ ± ०.०००००२६ | उपलब्ध नाही | 314 ms |
| 216 किरणोत्सारी | २१६.००२४२३६ ± ०.०००००३९ | उपलब्ध नाही | 300 us |
अवस्था / स्थिती
कारण: द्रवणांकापेक्षा (301.85 °C) 276.9 °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
85 पैकी 10 दाखवले आहेत. आयनाच्या विद्युतभारानुसार चढत्या क्रमाने मांडलेले.
वर्णरेषांचा संग्रह ?
| आयन | विद्युतभार | एकूण वर्णरेषा | संक्रमण संभाव्यता | पातळ्यांची नामांकने |
|---|---|---|---|---|
| At I | 0 | 2 | 0 | 2 |
ऊर्जा पातळ्यांचा संग्रह ?
| आयन | विद्युतभार | पातळ्या |
|---|---|---|
| At I | 0 | 4 |
| At II | +1 | 2 |
| At III | +2 | 2 |
| At IV | +3 | 2 |
| At V | +4 | 2 |
| At VI | +5 | 2 |
| At VII | +6 | 2 |
| At VIII | +7 | 2 |
| At IX | +8 | 2 |
| At X | +9 | 2 |
स्फटिक संरचनेची माहिती उपलब्ध नाही
आयनिक त्रिज्या
| विद्युतभार | समन्वय | प्रचक्रण | त्रिज्या |
|---|---|---|---|
| +7 | 6 | उपलब्ध नाही | 62 pm |
संयुगे
समस्थानिके (5)
| वस्तुमानांक | अणुवस्तुमान (u) | नैसर्गिक विपुलता | अर्धायुष्य | क्षय प्रकार | |
|---|---|---|---|---|---|
| 214 किरणोत्सारी | २१३.९९६३७२१ ± ०.०००००४६ | उपलब्ध नाही | 558 ns | α =100% | |
| 197 किरणोत्सारी | १९६.९९३१८९ ± ०.००००५५ | उपलब्ध नाही | 388.2 ms | α =96.1±1.2%β+ =3.9±1.2% | |
| 196 किरणोत्सारी | १९५.९९५८ ± ०.००००३३ | उपलब्ध नाही | 377 ms | α =97.5±0.3%β+ ?β+SF =0.009±0.1% | |
| 212 किरणोत्सारी | २११.९९०७३७७ ± ०.०००००२६ | उपलब्ध नाही | 314 ms | α ≈100%β+ ?β- ? | |
| 216 किरणोत्सारी | २१६.००२४२३६ ± ०.०००००३९ | उपलब्ध नाही | 300 us | α ≈100%β- ?ε ? |
विस्तारित गुणधर्म
सहसंयुजी त्रिज्या (विस्तारित)
- सहसंयुजी त्रिज्या (प्युक्को)
- 147 pm
- सहसंयुजी त्रिज्या (प्युक्को, दुहेरी बंध)
- 138 pm
- सहसंयुजी त्रिज्या (प्युक्को, तिहेरी बंध)
- 138 pm
व्हॅन डर वाल्स त्रिज्या
- Truhlar
- 202 pm
- UFF
- 475 pm
- MM3
- 251 pm
अणुत्रिज्या आणि धात्विक त्रिज्या
- अणुत्रिज्या (राह्म)
- 247 pm
क्रमांकन मापनपट्ट्या
- Mendeleev
- 110
- Pettifor
- 96
- Glawe
- 98
विद्युतऋणता मापनपट्ट्या
- Ghosh
- 0
- Gunnarsson–Lundqvist
- 7
- Robles–Bartolotti
- 6
ध्रुवणक्षमता आणि अपस्करण
- द्विध्रुव ध्रुवणक्षमता
- 42 a.u.
- द्विध्रुव ध्रुवणक्षमता (अनिश्चितता)
- 4 a.u.
- C₆ (Gould–Bučko)
- 351 Ha·Bohr6
अवस्थांतरे आणि अपरूपे
| द्रवणांक | 575.15 K |
ऑक्सिडीकरण अवस्थांचे वर्ग
प्रगत संदर्भ माहिती
परिरक्षण स्थिरांक (15)
| n | कक्षिका | σ |
|---|---|---|
| 1 | s | 1.6446 |
| 2 | p | 4.5524 |
| 2 | s | 22.3324 |
| 3 | d | 13.4155 |
| 3 | p | 23.5024 |
| 3 | s | 24.6481 |
| 4 | d | 37.9504 |
| 4 | f | 37.7596 |
| 4 | p | 36.516 |
| 4 | s | 35.6644 |
स्फटिक त्रिज्यांचा तपशील (1)
| विद्युतभार | CN | प्रचक्रण | rcrystal (pm) | उत्पत्ती |
|---|---|---|---|---|
| 7 | VI | 76 | Ahrens (1952) ionic radius, |
समस्थानिक क्षय प्रकार (76)
| समस्थानिक | मोड | तीव्रता |
|---|---|---|
| 191 | A | 100% |
| 191 | B+ | — |
| 192 | A | 100% |
| 192 | B+ | — |
| 192 | B+SF | 0.5% |
| 193 | A | 100% |
| 194 | A | 100% |
| 194 | B+ | 8.3% |
| 194 | B+SF | 0% |
| 195 | A | 100% |
क्ष-किरण प्रकीर्णन गुणक (516)
| ऊर्जा (eV) | f₁ | f₂ |
|---|---|---|
| 10 | — | 8.78144 |
| 10.1617 | — | 8.87321 |
| 10.3261 | — | 8.96593 |
| 10.4931 | — | 9.04836 |
| 10.6628 | — | 9.08532 |
| 10.8353 | — | 9.12244 |
| 11.0106 | — | 9.1597 |
| 11.1886 | — | 9.1933 |
| 11.3696 | — | 9.15142 |
| 11.5535 | — | 9.10973 |
अतिरिक्त माहिती
Estimated Crustal Abundance
The estimated element abundance in the earth's crust.
Not Applicable
संदर्भ (1)
- [5] Astatine https://education.jlab.org/itselemental/ele085.html
Estimated Oceanic Abundance
The estimated element abundance in the earth's oceans.
Not Applicable
संदर्भ (1)
- [5] Astatine https://education.jlab.org/itselemental/ele085.html
Production
Production of this element (from raw materials or other compounds containing the element).
Astatine can be produced by bombarding bismuth with energetic alpha particles to obtain the relatively long-lived 209-211At, which can be distilled from the target by heating in air.
संदर्भ (1)
- [6] Astatine https://periodic.lanl.gov/85.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 Astatine.
The element property data was retrieved from publications.