Astatine

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Astatine

Atomic Mass	210
Electron Configuration	[Xe]6s24f145d106p5
Oxidation States	7, 5, 3, 1, -1
Year Discovered	1940

Astatine

Atomic Mass	210
Electron Configuration	[Xe]6s24f145d106p5
Oxidation States	7, 5, 3, 1, -1
Year Discovered	1940

Identifiers

Element Name	Astatine
Element Symbol	At
InChI	InChI=1S/At
InChIKey	RYXHOMYVWAEKHL-UHFFFAOYSA-N

Properties

Atomic Weight	210 210 [210]
Electron Configuration	[Xe]6s²4f¹⁴5d¹⁰6p⁵
Atomic Radius	Van der Waals Atomic Radius : 202 pm (Van der Waals) Covalent Atomic Radius : 150 pm (Covalent)
Oxidation States	7, 5, 3, 1, -1
Ground Level	²P°_3/2
Ionization Energy	9.5 eV 9.31751 ± 0.00008 eV
Electronegativity	Pauling Scale Electronegativity : 2.2(Pauling Scale) Allen Scale Electronegativity : 2.39(Allen Scale)
Electron Affinity	2.8eV 2.8eV
Atomic Spectra	Lines Holdings Levels Holdings
Physical Description	Solid
Element Classification	Semi-metal
Element Period Number	6
Element Group Number	17 - Halogen
Density	about 7 grams per cubic centimeter
Melting Point	575 K (302°C or 576°F) 302°C
Boiling Point	337°C
Estimated Crustal Abundance	Not Applicable
Estimated Oceanic Abundance	Not Applicable

History

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.

Description

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.

Compounds

See more information at the Astatine compound page.

Element Forms

CID	Name	Formula	SMILES	Molecular Weight
6337078	astatine-211	At	[211At]	210.98750
5460479	astatine	At	[At]	209.98715
10443324	astatine-217	At	[217At]	217.00472
6337689	astatine-207	At	[207At]	206.9858
44154948	astatine-218	At	[218At]	218.0087
11458475	astatine-210	At	[210At]	209.98715

Isotopes

Stable Isotope Count	0

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]. 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].

Fig. IUPAC.85.1: ²¹¹At treats hyperthyroidism and thyroid cancer. (Image Source: © 2012 Terese Winslow LLC, U.S. Govt. has specified rights) [567].

[565] L. M. Cobb, A. Harrison, N. E. Dudley, T. E. F. Carr, J. A. Humphreys. Radiother. Oncol.13, 203 (1988).

[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.

[567] National Cancer Institute, National Institutes of Health. Thyroid And Parathyroid Gland Anatomy (2012). https://visualsonline.cancer.gov/details.cfm?imageid=9268.

Isotope Mass and Abundance

Isotope	Atomic Mass (uncertainty) [u]	Abundance (uncertainty)
²¹⁰At	209.9871479(83)
²¹¹At	210.9874966(30)

Atomic Mass, Half Life, and Decay

Nuclide	Atomic Mass and Uncertainty [u]	Half Life and Uncertainty	Discovery Year	Decay Modes, Intensities and Uncertainties [%]
¹⁹¹At	191.004148081 ± 0.000017287	2.1 ms ± 0.8	2003	α≈100%; β⁺ ?
¹⁹¹At^m	191.004148081 ± 0.000017287	2.2 ms ± 0.4	2003	α≈100%; β⁺ ?
¹⁹²At	192.003140912 ± 0.000029922	11.5 ms ± 0.6	2006	α=100%; β⁺ ?; β⁺SF<0.51%
¹⁹²At^m	192.003140912 ± 0.000029922	88 ms ± 6	2006	α=100%; β⁺ ?; β⁺SF<0.51%
¹⁹³At	192.999927725 ± 0.000023222	29 ms ± 5	2003	α≈100%
¹⁹³At^m	192.999927725 ± 0.000023222	21 ms ± 5	1995	α≈100%
¹⁹³Atⁿ	192.999927725 ± 0.000023222	28 ms ± 4	2003	IT=76±1%; α=24±1%
¹⁹⁴At	193.999230816 ± 0.00002523	286 ms ± 7	2009	α≈100%; β⁺=8.3%[Estimated]; β⁺SF=0.032%[Estimated]
¹⁹⁴At^m	193.999230816 ± 0.00002523	323 ms ± 7	1984	α≈100%; β⁺=8.3%[Estimated]; β⁺SF=0.032%[Estimated]
¹⁹⁵At	194.996274480 ± 0.000010276	290 ms ± 20	1999	α≈100%; β⁺ ?
¹⁹⁵At^m	194.996274480 ± 0.000010276	143 ms ± 3	1995	α=88±0.4%; IT=12±0.4%; β⁺ ?
¹⁹⁵At^p	194.996274480 ± 0.000010276	Not-specified		IT ?
¹⁹⁶At	195.995799034 ± 0.000032458	377 ms ± 4	1967	α=97.5±0.3%; β⁺ ?; β⁺SF=0.009±0.1%
¹⁹⁶At^m	195.995799034 ± 0.000032458	20 ms [Estimated]	1996	α≈100%
¹⁹⁶Atⁿ	195.995799034 ± 0.000032458	11 us ± 2	2000	IT=100%
¹⁹⁷At	196.993177353 ± 0.00000857	388.2 ms ± 5.6	1967	α=96.1±1.2%; β⁺=3.9±1.2%
¹⁹⁷At^m	196.993177353 ± 0.00000857	2.0 s ± 0.2	1985	α≈100%; β⁺ ?; IT<0.004%; β⁺ ?
¹⁹⁷Atⁿ	196.993177353 ± 0.00000857	1.3 us ± 0.2	1999	IT=100%
¹⁹⁸At	197.992797864 ± 0.000005265	4.47 s ± 0.05	1967	α≈97.0±1.7%; β⁺ ?
¹⁹⁸At^m	197.992797864 ± 0.000005265	1.23 s ± 0.05	1967	α=93±0.4%; β⁺ ?
¹⁹⁹At	198.990527715 ± 0.00000578	7.02 s ± 0.12	1967	α=89±0.6%; β⁺ ?
¹⁹⁹At^m	198.990527715 ± 0.00000578	273 ms ± 9	2013	IT≈99%; α≈1%
¹⁹⁹Atⁿ	198.990527715 ± 0.00000578	70 ns ± 20	2000	IT=100%
¹⁹⁹At^p	198.990527715 ± 0.00000578	800 ns ± 50	2010	IT=100%
²⁰⁰At	199.990351099 ± 0.000026264	43.2 s ± 0.9	1963	α=52±0.3%; β⁺=48±0.3%
²⁰⁰At^m	199.990351099 ± 0.000026264	47 s ± 1	1967	α=43±0.7%; β⁺=57±0.7%; IT ?
²⁰⁰Atⁿ	199.990351099 ± 0.000026264	8.0 s ± 2.1	1967	IT ?; α≈10.5±0.3%; β⁺ ?
²⁰¹At	200.988417058 ± 0.000008786	85.2 s ± 1.6	1963	α=71±0.7%; β⁺=29±0.7%
²⁰¹At^m	200.988417058 ± 0.000008786	45 ms ± 3	2015	IT=100%
²⁰¹Atⁿ	200.988417058 ± 0.000008786	3.39 us ± 0.09	2015	IT=100%
²⁰²At	201.988625686 ± 0.000029631	184 s ± 1	1961	β⁺=88±0.7%; α=12±0.7%
²⁰²At^m	201.988625686 ± 0.000029631	182 s ± 2	1992	β⁺=91.5±1.5%; α=8.5±1.5%; IT ?
²⁰²Atⁿ	201.988625686 ± 0.000029631	460 ms ± 50	1992	IT=99.904±1.1%; α=0.096±1.1%; β⁺ ?
²⁰³At	202.986942904 ± 0.000011404	7.4 m ± 0.2	1951	β⁺=69±0.3%; α=31±0.3%
²⁰³At^m	202.986942904 ± 0.000011404	3.5 ms ± 0.6	2017	IT=100%
²⁰³Atⁿ	202.986942904 ± 0.000011404	9.77 us ± 0.21	2018	IT=100%
²⁰⁴At	203.987251393 ± 0.000024335	9.12 m ± 0.11	1961	β⁺=96.2±0.2%; α=3.8±0.2%
²⁰⁴At^m	203.987251393 ± 0.000024335	108 ms ± 10	1969	IT=100%
²⁰⁵At	204.986060546 ± 0.000012941	26.9 m ± 0.8	1951	β⁺=90±0.2%; α=10±0.2%
²⁰⁵At^m	204.986060546 ± 0.000012941	7.76 us ± 0.14	1982	IT=100%
²⁰⁶At	205.986645768 ± 0.000014523	30.6 m ± 0.8	1961	β⁺=99.10±0.8%; α=0.90±0.8%
²⁰⁶At^m	205.986645768 ± 0.000014523	813 ns ± 21	1999	IT=100%
²⁰⁷At	206.985799715 ± 0.000013318	1.81 h ± 0.03	1951	β⁺≈90%; α≈10%
²⁰⁷At^m	206.985799715 ± 0.000013318	108 ns ± 2	1981	IT=100%
²⁰⁸At	207.986613011 ± 0.000009577	1.63 h ± 0.03	1950	β⁺=99.45±0.6%; α=0.55±0.6%
²⁰⁸At^m	207.986613011 ± 0.000009577	1.5 us ± 0.2	1991	IT=100%
²⁰⁹At	208.986168701 ± 0.000005094	5.42 h ± 0.05	1951	β⁺=96.1±0.4%; α=3.9±0.4%
²⁰⁹At^m	208.986168701 ± 0.000005094	916 ns ± 10	1975	IT=100%
²¹⁰At	209.987147423 ± 0.000008261	8.1 h ± 0.4	1949	β⁺=99.825±2%; α=0.175±2%
²¹⁰At^m	209.987147423 ± 0.000008261	482 ns ± 6	1970	IT=100%
²¹⁰Atⁿ	209.987147423 ± 0.000008261	5.66 us ± 0.07	1975	IT=100%
²¹¹At	210.987496226 ± 0.000002929	7.214 h ± 0.007	1940	ε=58.20±0.8%; α=41.80±0.8%
²¹¹At^m	210.987496226 ± 0.000002929	4.23 us ± 0.07	1971	IT=100%
²¹²At	211.990737301 ± 0.000002559	314 ms ± 3	1954	α≈100%; β⁺ ?; β^- ?
²¹²At^m	211.990737301 ± 0.000002559	119 ms ± 3	1970	α≈100%; IT ?
²¹²Atⁿ	211.990737301 ± 0.000002559	152 us ± 5	1998	IT=100%
²¹³At	212.992936593 ± 0.000005258	125 ns ± 6	1968	α=100%
²¹³At^m	212.992936593 ± 0.000005258	110 ns ± 17	1980	IT=100%
²¹³Atⁿ	212.992936593 ± 0.000005258	45 us ± 4	2003	IT=100%
²¹⁴At	213.996372331 ± 0.000004274	558 ns ± 10	1949	α=100%
²¹⁴At^m	213.996372331 ± 0.000004274	265 ns ± 30	1982	α≈100%; IT ?
²¹⁴Atⁿ	213.996372331 ± 0.000004274	760 ns ± 15	1982	α≈100%; IT ?
²¹⁵At	214.998651002 ± 0.000007116	37 us ± 3	1944	α=100%
²¹⁶At	216.002422643 ± 0.000003837	300 us ± 30	1948	α≈100%; β^- ?; ε ?
²¹⁶At^m	216.002422643 ± 0.000003837	100 us [Estimated]	1971	α=100%
²¹⁷At	217.004717794 ± 0.000005368	32.6 ms ± 0.3	1947	α=99.992±0.2%; β^-=0.008±0.2%
²¹⁸At	218.008695941 ± 0.000012349	1.28 s ± 0.06	1943	α≈100%; β^- ?
²¹⁹At	219.011160587 ± 0.000003474	56 s ± 3	1953	α=93.6±1%; β^-=6.4±1%
²²⁰At	220.015433000 ± 0.000015	3.71 m ± 0.04	1989	β^-=92±0.2%; α=8±0.2%
²²¹At	221.018017000 ± 0.000015	2.3 m ± 0.2	1989	β^-=100%
²²²At	222.022494000 ± 0.000017	54 s ± 10	1989	β^-=100%
²²³At	223.025151000 ± 0.000015	50 s ± 7	1989	β^-≈100%; α ?
²²⁴At	224.029749000 ± 0.000024	2.5 m ± 1.5	2010	β^-=100%
²²⁵At	225.032528 ± 0.000322 [Estimated]	3 s >300ns [Estimated]	2010	β^- ?; β^-n ?
²²⁶At	226.037209 ± 0.000322 [Estimated]	7 m >300ns [Estimated]	2010	β^- ?; β^-n ?
²²⁷At	227.040183 ± 0.000322 [Estimated]	5 s >300ns [Estimated]	2010	β^- ?; β^-n ?
²²⁸At	228.044960 ± 0.000429 [Estimated]	1 m >300ns [Estimated]	2010	β^- ?; β^-n ?
²²⁹At	229.048191 ± 0.000429 [Estimated]	1 s >300ns [Estimated]	2010	β^- ?; β^-n ?

Information Sources

Astatine

View products including Astatine ➡︎

Identifiers

Properties

History

Description

Users

Compounds

Element Forms

Isotopes

Isotopes in Medicine

Isotope Mass and Abundance

Atomic Mass, Half Life, and Decay

Information Sources