Astatine

Astatine (At)

Radioactive halogen element. Occurs naturally from uranium and thorium decay. At least 20 known isotopes. At-210, the most stable, has a half-life of 8.3 hours. Synthesized by nuclear bombardment in 1940 by D.R. Corson, K.R. MacKenzie and E. Segre at the University of California.
Atomic Number85
Atomic Weight210
Mass Number191
Group17
Period6
Blockp
Protons85 p+
Neutrons106 n0
Electrons85 e-
Animated Bohr Model of At (Astatine)

Properties

Atomic Radius
Molar Volume
Covalent Radius
147 pm
Metallic Radius
Ionic Radius
62 pm
Crystal Radius
76 pm
Van der Waals Radius
202 pm
Density
Energy
Proton Affinity
Electron Affinity
Ionization Energy
9.31751 eV/particle
Ionization Energies of At (Astatine)
Heat of Vaporization
Heat of Fusion
Heat of Formation
Electrons
Electron Shells2, 8, 18, 32, 18, 7
Bohr Model: At (Astatine)
Valence Electrons7
Lewis Structure: At (Astatine)
Electron Configuration[Xe] 4f14 5d10 6s2 6p5
Enhanced Bohr Model of At (Astatine)
Orbital Diagram of At (Astatine)
Oxidation States-1, 1, 3, 5, 7
Electronegativity
2.2
Electrophilicity
2.8161454412824063 eV/particle
Phases
PhaseSolid
Gas Phase
Boiling Point
Melting Point
575.15 K
Critical Pressure
Critical Temperature
Triple Point
Visual
Color
Silver
Appearanceunknown, probably metallic
Refractive Index
Thermodynamic Properties
Thermal Conductivity
Thermal Expansion
Molar Heat Capacity
Specific Heat Capacity
Heat Capacity Ratio (Adiabatic Index)
Electrical Properties
Type
Electrical Conductivity
Electrical Resistivity
Superconducting Point
Magnetism
Type
Magnetic Susceptibility (Mass)
Magnetic Susceptibility (Molar)
Magnetic Susceptibility (Volume)
Magnetic Ordering
Curie Point
Neel Point
Structure
Crystal Structure ()
Lattice Constant
Lattice Angles
Mechanical Properties
Hardness
Bulk Modulus
Shear Modulus
Young Modulus
Poisson Ratio
Speed of Sound
Classification
CategoryHalogens, Halogens
CAS GroupVIIB
IUPAC GroupVIIA
Glawe Number98
Mendeleev Number110
Pettifor Number96
Geochemical ClassU/Th decay series
Goldschmidt Classsynthetic
Other
Gas Basicity
Dipole Polarizability
42 ± 4 a₀
C6 Dispersion Coefficient
Allotropes
Neutron Cross Section
Neutron Mass Absorption
Quantum Numbers2P3/2
Space Group ()

Isotopes of Astatine

Stable Isotopes0
Unstable Isotopes39
Radioactive Isotopes39

191At

AbundanceRadioactive ☢️
Relative Atomic Mass
191.004148081 ± 0.000017287 Da
Mass Number191
G-Factor
Half Life
2.1 ± 0.8 ms
Spin1/2
Quadrupole Moment
0
Discovery Year2003
Parity+

191At Decay Modes
Decay ModeIntensity
α (α emission)100%
β+ (β+ decay; β+ = ϵ + e+)%

192At

AbundanceRadioactive ☢️
Relative Atomic Mass
192.003140912 ± 0.000029922 Da
Mass Number192
G-Factor
Half Life
11.5 ± 0.6 ms
Spin3
Quadrupole Moment
Discovery Year2006
Parity+

192At Decay Modes
Decay ModeIntensity
α (α emission)100%
β+ (β+ decay; β+ = ϵ + e+)%
β+ SF (β+-delayed fission)0.51%

193At

AbundanceRadioactive ☢️
Relative Atomic Mass
192.999927725 ± 0.000023222 Da
Mass Number193
G-Factor
Half Life
29 ± 5 ms
Spin1/2
Quadrupole Moment
0
Discovery Year2003
Parity+

193At Decay Modes
Decay ModeIntensity
α (α emission)100%

194At

AbundanceRadioactive ☢️
Relative Atomic Mass
193.999230816 ± 0.00002523 Da
Mass Number194
G-Factor
Half Life
286 ± 7 ms
Spin5
Quadrupole Moment
Discovery Year2009
Parity-

194At Decay Modes
Decay ModeIntensity
α (α emission)100%
β+ (β+ decay; β+ = ϵ + e+)8.3%
β+ SF (β+-delayed fission)0.032%

195At

AbundanceRadioactive ☢️
Relative Atomic Mass
194.99627448 ± 0.000010276 Da
Mass Number195
G-Factor
3.2 ± 0.1
Half Life
290 ± 20 ms
Spin1/2
Quadrupole Moment
0
Discovery Year1999
Parity+

195At Decay Modes
Decay ModeIntensity
α (α emission)100%
β+ (β+ decay; β+ = ϵ + e+)%

196At

AbundanceRadioactive ☢️
Relative Atomic Mass
195.995799034 ± 0.000032458 Da
Mass Number196
G-Factor
1.24 ± 0.046666666666667
Half Life
377 ± 4 ms
Spin3
Quadrupole Moment
-0.6 ± 0.4
Discovery Year1967
Parity+

196At Decay Modes
Decay ModeIntensity
α (α emission)97.5%
β+ (β+ decay; β+ = ϵ + e+)%
β+ SF (β+-delayed fission)0.009%

197At

AbundanceRadioactive ☢️
Relative Atomic Mass
196.993177353 ± 0.00000857 Da
Mass Number197
G-Factor
0.85111111111111 ± 0.015555555555556
Half Life
388.2 ± 5.6 ms
Spin9/2
Quadrupole Moment
-1.2 ± 0.6
Discovery Year1967
Parity-

197At Decay Modes
Decay ModeIntensity
α (α emission)96.1%
β+ (β+ decay; β+ = ϵ + e+)3.9%

198At

AbundanceRadioactive ☢️
Relative Atomic Mass
197.992797864 ± 0.000005265 Da
Mass Number198
G-Factor
1.34 ± 0.046666666666667
Half Life
4.47 ± 0.05 s
Spin3
Quadrupole Moment
-0.6 ± 0.3
Discovery Year1967
Parity+

198At Decay Modes
Decay ModeIntensity
α (α emission)97%
β+ (β+ decay; β+ = ϵ + e+)%

199At

AbundanceRadioactive ☢️
Relative Atomic Mass
198.990527715 ± 0.00000578 Da
Mass Number199
G-Factor
0.87555555555556 ± 0.015555555555556
Half Life
7.02 ± 0.12 s
Spin9/2
Quadrupole Moment
-1 ± 0.5
Discovery Year1967
Parity-

199At Decay Modes
Decay ModeIntensity
α (α emission)89%
β+ (β+ decay; β+ = ϵ + e+)%

200At

AbundanceRadioactive ☢️
Relative Atomic Mass
199.990351099 ± 0.000026264 Da
Mass Number200
G-Factor
1.4266666666667 ± 0.05
Half Life
43.2 ± 0.9 s
Spin3
Quadrupole Moment
-0.5 ± 0.5
Discovery Year1963
Parity+

200At Decay Modes
Decay ModeIntensity
α (α emission)52%
β+ (β+ decay; β+ = ϵ + e+)48%

201At

AbundanceRadioactive ☢️
Relative Atomic Mass
200.988417058 ± 0.000008786 Da
Mass Number201
G-Factor
0.89111111111111 ± 0.015555555555556
Half Life
85.2 ± 1.6 s
Spin9/2
Quadrupole Moment
-1 ± 0.5
Discovery Year1963
Parity-

201At Decay Modes
Decay ModeIntensity
α (α emission)71%
β+ (β+ decay; β+ = ϵ + e+)29%

202At

AbundanceRadioactive ☢️
Relative Atomic Mass
201.988625686 ± 0.000029631 Da
Mass Number202
G-Factor
1.38 ± 0.053333333333333
Half Life
184 ± 1 s
Spin3
Quadrupole Moment
-0.5 ± 0.3
Discovery Year1961
Parity+

202At Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)88%
α (α emission)12%

203At

AbundanceRadioactive ☢️
Relative Atomic Mass
202.986942904 ± 0.000011404 Da
Mass Number203
G-Factor
0.88888888888889 ± 0.015555555555556
Half Life
7.4 ± 0.2 m
Spin9/2
Quadrupole Moment
-0.7 ± 0.4
Discovery Year1951
Parity-

203At Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)69%
α (α emission)31%

204At

AbundanceRadioactive ☢️
Relative Atomic Mass
203.987251393 ± 0.000024335 Da
Mass Number204
G-Factor
0.68857142857143 ± 0.025714285714286
Half Life
9.12 ± 0.11 m
Spin7
Quadrupole Moment
-0.6 ± 0.3
Discovery Year1961
Parity+

204At Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)96.2%
α (α emission)3.8%

205At

AbundanceRadioactive ☢️
Relative Atomic Mass
204.986060546 ± 0.000012941 Da
Mass Number205
G-Factor
0.90888888888889 ± 0.015555555555556
Half Life
26.9 ± 0.8 m
Spin9/2
Quadrupole Moment
-0.6 ± 0.3
Discovery Year1951
Parity-

205At Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)90%
α (α emission)10%

206At

AbundanceRadioactive ☢️
Relative Atomic Mass
205.986645768 ± 0.000014523 Da
Mass Number206
G-Factor
0.72833333333333 ± 0.028333333333333
Half Life
30.6 ± 0.8 m
Spin6
Quadrupole Moment
-0.4 ± 0.2
Discovery Year1961
Parity

206At Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)99.1%
α (α emission)0.9%

207At

AbundanceRadioactive ☢️
Relative Atomic Mass
206.985799715 ± 0.000013318 Da
Mass Number207
G-Factor
0.91777777777778 ± 0.015555555555556
Half Life
1.81 ± 0.03 h
Spin9/2
Quadrupole Moment
-0.5 ± 0.3
Discovery Year1951
Parity-

207At Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)90%
α (α emission)10%

208At

AbundanceRadioactive ☢️
Relative Atomic Mass
207.986613011 ± 0.000009577 Da
Mass Number208
G-Factor
0.74333333333333 ± 0.03
Half Life
1.63 ± 0.03 h
Spin6
Quadrupole Moment
-0.4 ± 0.3
Discovery Year1950
Parity+

208At Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)99.45%
α (α emission)0.55%

209At

AbundanceRadioactive ☢️
Relative Atomic Mass
208.986168701 ± 0.000005094 Da
Mass Number209
G-Factor
0.91555555555556 ± 0.015555555555556
Half Life
5.42 ± 0.05 h
Spin9/2
Quadrupole Moment
-0.4 ± 0.2
Discovery Year1951
Parity-

209At Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)96.1%
α (α emission)3.9%

210At

AbundanceRadioactive ☢️
Relative Atomic Mass
209.987147423 ± 0.000008261 Da
Mass Number210
G-Factor
0.944 ± 0.032
Half Life
8.1 ± 0.4 h
Spin5
Quadrupole Moment
-0.4 ± 0.2
Discovery Year1949
Parity

210At Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)99.825%
α (α emission)0.175%

211At

AbundanceRadioactive ☢️
Relative Atomic Mass
210.987496226 ± 0.000002929 Da
Mass Number211
G-Factor
0.92 ± 0.0088888888888889
Half Life
7.214 ± 0.007 h
Spin9/2
Quadrupole Moment
Discovery Year1940
Parity-

211At Decay Modes
Decay ModeIntensity
ϵ (electron capture)58.2%
α (α emission)41.8%

212At

AbundanceRadioactive ☢️
Relative Atomic Mass
211.990737301 ± 0.000002559 Da
Mass Number212
G-Factor
Half Life
314 ± 3 ms
Spin1
Quadrupole Moment
Discovery Year1954
Parity-

212At Decay Modes
Decay ModeIntensity
α (α emission)100%
β+ (β+ decay; β+ = ϵ + e+)%
β (β decay)%

213At

AbundanceRadioactive ☢️
Relative Atomic Mass
212.992936593 ± 0.000005258 Da
Mass Number213
G-Factor
Half Life
125 ± 6 ns
Spin9/2
Quadrupole Moment
Discovery Year1968
Parity-

213At Decay Modes
Decay ModeIntensity
α (α emission)100%

214At

AbundanceRadioactive ☢️
Relative Atomic Mass
213.996372331 ± 0.000004274 Da
Mass Number214
G-Factor
Half Life
558 ± 10 ns
Spin1
Quadrupole Moment
Discovery Year1949
Parity-

214At Decay Modes
Decay ModeIntensity
α (α emission)100%

215At

AbundanceRadioactive ☢️
Relative Atomic Mass
214.998651002 ± 0.000007116 Da
Mass Number215
G-Factor
Half Life
37 ± 3 us
Spin9/2
Quadrupole Moment
Discovery Year1944
Parity-

215At Decay Modes
Decay ModeIntensity
α (α emission)100%

216At

AbundanceRadioactive ☢️
Relative Atomic Mass
216.002422643 ± 0.000003837 Da
Mass Number216
G-Factor
Half Life
300 ± 30 us
Spin1
Quadrupole Moment
Discovery Year1948
Parity-

216At Decay Modes
Decay ModeIntensity
α (α emission)100%
β (β decay)%
ϵ (electron capture)%

217At

AbundanceRadioactive ☢️
Relative Atomic Mass
217.004717794 ± 0.000005368 Da
Mass Number217
G-Factor
0.84444444444444 ± 0.044444444444444
Half Life
32.6 ± 0.3 ms
Spin9/2
Quadrupole Moment
Discovery Year1947
Parity-

217At Decay Modes
Decay ModeIntensity
α (α emission)99.992%
β (β decay)0.008%

218At

AbundanceRadioactive ☢️
Relative Atomic Mass
218.008695941 ± 0.000012349 Da
Mass Number218
G-Factor
Half Life
1.28 ± 0.06 s
Spin2
Quadrupole Moment
Discovery Year1943
Parity-

218At Decay Modes
Decay ModeIntensity
α (α emission)100%
β (β decay)%

219At

AbundanceRadioactive ☢️
Relative Atomic Mass
219.011160587 ± 0.000003474 Da
Mass Number219
G-Factor
Half Life
56 ± 3 s
Spin9/2
Quadrupole Moment
Discovery Year1953
Parity-

219At Decay Modes
Decay ModeIntensity
α (α emission)93.6%
β (β decay)6.4%

220At

AbundanceRadioactive ☢️
Relative Atomic Mass
220.015433 ± 0.000015 Da
Mass Number220
G-Factor
Half Life
3.71 ± 0.04 m
Spin3
Quadrupole Moment
Discovery Year1989
Parity-

220At Decay Modes
Decay ModeIntensity
β (β decay)92%
α (α emission)8%

221At

AbundanceRadioactive ☢️
Relative Atomic Mass
221.018017 ± 0.000015 Da
Mass Number221
G-Factor
Half Life
2.3 ± 0.2 m
Spin3/2
Quadrupole Moment
Discovery Year1989
Parity-

221At Decay Modes
Decay ModeIntensity
β (β decay)100%

222At

AbundanceRadioactive ☢️
Relative Atomic Mass
222.022494 ± 0.000017 Da
Mass Number222
G-Factor
Half Life
54 ± 10 s
Spin
Quadrupole Moment
Discovery Year1989
Parity

222At Decay Modes
Decay ModeIntensity
β (β decay)100%

223At

AbundanceRadioactive ☢️
Relative Atomic Mass
223.025151 ± 0.000015 Da
Mass Number223
G-Factor
Half Life
50 ± 7 s
Spin3/2
Quadrupole Moment
Discovery Year1989
Parity-

223At Decay Modes
Decay ModeIntensity
β (β decay)100%
α (α emission)%

224At

AbundanceRadioactive ☢️
Relative Atomic Mass
224.029749 ± 0.000024 Da
Mass Number224
G-Factor
Half Life
2.5 ± 1.5 m
Spin2
Quadrupole Moment
Discovery Year2010
Parity+

224At Decay Modes
Decay ModeIntensity
β (β decay)100%

225At

AbundanceRadioactive ☢️
Relative Atomic Mass
225.032528 ± 0.000322 Da
Mass Number225
G-Factor
Half Life
Spin1/2
Quadrupole Moment
0
Discovery Year2010
Parity+

225At Decay Modes
Decay ModeIntensity
β (β decay)%
β n (β-delayed neutron emission)%

226At

AbundanceRadioactive ☢️
Relative Atomic Mass
226.037209 ± 0.000322 Da
Mass Number226
G-Factor
Half Life
Spin2
Quadrupole Moment
Discovery Year2010
Parity+

226At Decay Modes
Decay ModeIntensity
β (β decay)%
β n (β-delayed neutron emission)%

227At

AbundanceRadioactive ☢️
Relative Atomic Mass
227.040183 ± 0.000322 Da
Mass Number227
G-Factor
Half Life
Spin1/2
Quadrupole Moment
0
Discovery Year2010
Parity+

227At Decay Modes
Decay ModeIntensity
β (β decay)%
β n (β-delayed neutron emission)%

228At

AbundanceRadioactive ☢️
Relative Atomic Mass
228.04496 ± 0.000429 Da
Mass Number228
G-Factor
Half Life
Spin3
Quadrupole Moment
Discovery Year2010
Parity+

228At Decay Modes
Decay ModeIntensity
β (β decay)%
β n (β-delayed neutron emission)%

229At

AbundanceRadioactive ☢️
Relative Atomic Mass
229.048191 ± 0.000429 Da
Mass Number229
G-Factor
Half Life
Spin1/2
Quadrupole Moment
0
Discovery Year2010
Parity+

229At Decay Modes
Decay ModeIntensity
β (β decay)%
β n (β-delayed neutron emission)%
Electron shell 085 Astatine.svg

History

In 1869, existence of astatine was first predicted by Russian chemist Dmitri Mendeleev and called the element eka-iodine. In 1940, Dale R. Corson, Kenneth Ross MacKenzie, and Emilio Segrè isolated the element at the University of California, Berkeley. Instead of searching for the element in nature, the scientists created it by bombarding bismuth-209 with alpha particles. From the Greek astatos meaning unstable

DiscoverersD.R.Corson, K.R.MacKenzie, E.Segré
Discovery LocationUnited States
Discovery Year1940
Etymology (Name Origin)Greek: astatos (unstable).
PronunciationAS-teh-teen (English)
Astatine is highly radioactive
Astatine is preferentially concentrated in the thyroid gland

Uses

The newly formed astatine-211 is important in nuclear medicine. Once produced, astatine must be used quickly, as it decays with a half-life of 7.2 hours. Astatine-211 can be used for targeted alpha particle radiotherapy, since it decays either via emission of an alpha particle. Since its isotopes have such short half-lives there are no commercially significant compounds of astatine.

Sources

Does not occur in nature. Similar to iodine. Produced by bombarding bismuth with alpha particles.

Abundance
Abundance in Earth's crust
Abundance in Oceans
Abundance in Human Body
0 %
Abundance in Meteor
0 %
Abundance in Sun
Abundance in Universe
0 %

Nuclear Screening Constants

1s1.6446
2p4.5524
2s22.3324
3d13.4155
3p23.5024
3s24.6481
4d37.9504
4f37.7596
4p36.516
4s35.6644
5d58.661
5p53.96
5s52.0665
6p69.8368
6s67.7002