Astatine (At)
halogenSolid
Standard Atomic Weight
[210]Electron configuration
[Xe] 6s2 4f14 5d10 6p5Melting point
301.85 °C (575 K)Boiling point
N/ADensity
7000 kg/m³Oxidation states
−1, +1, +3, +5, +7Electronegativity (Pauling)
2.2Ionization energy (1st)
Discovery year
1940Atomic radius
N/ADetails
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.
Images
Properties
Physical
Chemical
Thermodynamic
Nuclear
Abundance
N/A
Reactivity
N/A
Crystal Structure
N/A
Electronic Structure
Identifiers
Electron Configuration Measured
At: 4f¹⁴ 5d¹⁰ 6s² 6p⁵[Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁵1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶ 4f¹⁴ 5d¹⁰ 6s² 6p⁵Atomic model
Isotopes change neutron count, mass, and stability — not the electron configuration of a neutral atom.
Schematic atomic model, not to scale.
Atomic Fingerprint
Emission / Absorption Spectrum
Isotope Distribution
No stable isotopes.
| Mass number | Atomic mass (u) | Natural abundance | Half-life |
|---|---|---|---|
| 214 Radioactive | 213.9963721 ± 0.0000046 | N/A | 558 ns |
| 197 Radioactive | 196.993189 ± 0.000055 | N/A | 388.2 ms |
| 196 Radioactive | 195.9958 ± 0.000033 | N/A | 377 ms |
| 212 Radioactive | 211.9907377 ± 0.0000026 | N/A | 314 ms |
| 216 Radioactive | 216.0024236 ± 0.0000039 | N/A | 300 us |
Phase / State
Reason: 276.9 °C below melting point (301.85 °C)
Schematic, not to scale
Phase transition points
Transition energies
Energy required to melt 1 mol at melting point
Energy required to vaporize 1 mol at boiling point
Energy required to sublime 1 mol at sublimation point
Density
At standard conditions
At standard conditions
Atomic Spectra
Showing 10 of 85 Atomic Spectra. Sorted by ion charge (ascending).
Lines Holdings ?
| Ion | Charge | Total lines | Transition probabilities | Level designations |
|---|---|---|---|---|
| At I | 0 | 2 | 0 | 2 |
Levels Holdings ?
| Ion | Charge | Levels |
|---|---|---|
| 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 |
Crystal structure data not available
Ionic Radii
| Charge | Coordination | Spin | Radius |
|---|---|---|---|
| +7 | 6 | N/A | 62 pm |
Compounds
Isotopes (5)
| Mass number | Atomic mass (u) | Natural abundance | Half-life | Decay mode | |
|---|---|---|---|---|---|
| 214 Radioactive | 213.9963721 ± 0.0000046 | N/A | 558 ns | α =100% | |
| 197 Radioactive | 196.993189 ± 0.000055 | N/A | 388.2 ms | α =96.1±1.2%β+ =3.9±1.2% | |
| 196 Radioactive | 195.9958 ± 0.000033 | N/A | 377 ms | α =97.5±0.3%β+ ?β+SF =0.009±0.1% | |
| 212 Radioactive | 211.9907377 ± 0.0000026 | N/A | 314 ms | α ≈100%β+ ?β- ? | |
| 216 Radioactive | 216.0024236 ± 0.0000039 | N/A | 300 us | α ≈100%β- ?ε ? |
Extended Properties
Covalent Radii (Extended)
Van der Waals Radii
Atomic & Metallic Radii
Numbering Scales
Electronegativity Scales
Polarizability & Dispersion
Phase Transitions & Allotropes
| Melting point | 575.15 K |
Oxidation State Categories
Advanced Reference Data
Screening Constants (15)
| n | Orbital | 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 |
Crystal Radii Detail (1)
| Charge | CN | Spin | rcrystal (pm) | Origin |
|---|---|---|---|---|
| 7 | VI | 76 | Ahrens (1952) ionic radius, |
Isotope Decay Modes (76)
| Isotope | Mode | Intensity |
|---|---|---|
| 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% |
X‑ray Scattering Factors (516)
| Energy (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 |
Additional Data
Estimated Crustal Abundance
The estimated element abundance in the earth's crust.
Not Applicable
References (1)
- [5] Astatine https://education.jlab.org/itselemental/ele085.html
Estimated Oceanic Abundance
The estimated element abundance in the earth's oceans.
Not Applicable
References (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.
References (1)
- [6] Astatine https://periodic.lanl.gov/85.shtml
References
(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.