Francium

Francium (Fr)

Radioactive element, belongs to group 1 of the periodic table. Found in uranium and thorium ores. The 22 known isotopes are all radioactive, with the most stable being Fr-223. Its existence was confirmed in 1939 by Marguerite Perey.
Atomic Number87
Atomic Weight223
Mass Number197
Group1
Period7
Blocks
Protons87 p+
Neutrons110 n0
Electrons87 e-
Electron shell 087 francium.png Animated Bohr Model of Fr (Francium) Enhanced Bohr Model of Fr (Francium) Bohr Model: Fr (Francium) Orbital Diagram of Fr (Francium)

Properties

Atomic Radius
Molar Volume
Covalent Radius
223 pm
Metallic Radius
Ionic Radius
180 pm
Crystal Radius
194 pm
Van der Waals Radius
348 pm
Density
1.87 g/cm³
Energy
Proton Affinity
Electron Affinity
Ionization Energy
4.0727409 eV/particle
Heat of Vaporization
Heat of Fusion
Heat of Formation
Electrons
Electron Shells2, 8, 18, 32, 18, 8, 1
Valence Electrons1
Electron Configuration[Rn] 7s1
Oxidation States1
Electronegativity
0.7
Electrophilicity
0.7242688826969913 eV/particle
Phases
PhaseSolid
Gas Phase
Boiling Point
Melting Point
294.15 K
Critical Pressure
Critical Temperature
Triple Point
Visual
Color
Silver
Appearance
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 (BCC)
Lattice Constant
Lattice Angles
Mechanical Properties
Hardness
Bulk Modulus
Shear Modulus
Young Modulus
Poisson Ratio
Speed of Sound
Classification
CategoryAlkali metals, Alkali metals
CAS GroupIA
IUPAC GroupIA
Glawe Number7
Mendeleev Number6
Pettifor Number7
Geochemical ClassU/Th decay series
Goldschmidt Classsynthetic
Other
Gas Basicity
Dipole Polarizability
317.8 ± 2.4 a₀
C6 Dispersion Coefficient
Allotropes
Neutron Cross Section
Neutron Mass Absorption
Quantum Numbers2S1/2
Space Group ()

Isotopes of Francium

Stable Isotopes0
Unstable Isotopes37
Radioactive Isotopes37

197Fr

AbundanceRadioactive ☢️
Relative Atomic Mass
197.011008086 ± 0.000060584 Da
Mass Number197
G-Factor
Half Life
2.3 ± 1.9 ms
Spin7/2
Quadrupole Moment
Discovery Year2013
Parity-

197Fr Decay Modes
Decay ModeIntensity
α (α emission)100%

198Fr

AbundanceRadioactive ☢️
Relative Atomic Mass
198.010282081 ± 0.000033419 Da
Mass Number198
G-Factor
Half Life
15 ± 3 ms
Spin3
Quadrupole Moment
Discovery Year2013
Parity+

198Fr Decay Modes
Decay ModeIntensity
α (α emission)100%

199Fr

AbundanceRadioactive ☢️
Relative Atomic Mass
199.007269384 ± 0.000014734 Da
Mass Number199
G-Factor
Half Life
6.6 ± 2.2 ms
Spin1/2
Quadrupole Moment
0
Discovery Year1999
Parity+

199Fr Decay Modes
Decay ModeIntensity
α (α emission)100%
β+ (β+ decay; β+ = ϵ + e+)%

200Fr

AbundanceRadioactive ☢️
Relative Atomic Mass
200.006584666 ± 0.000032769 Da
Mass Number200
G-Factor
Half Life
47.5 ± 2.8 ms
Spin3
Quadrupole Moment
Discovery Year1995
Parity+

200Fr Decay Modes
Decay ModeIntensity
α (α emission)100%
β+ (β+ decay; β+ = ϵ + e+)%
β+ SF (β+-delayed fission)%

201Fr

AbundanceRadioactive ☢️
Relative Atomic Mass
201.003852491 ± 0.000009747 Da
Mass Number201
G-Factor
Half Life
62.8 ± 1.9 ms
Spin9/2
Quadrupole Moment
Discovery Year1980
Parity-

201Fr Decay Modes
Decay ModeIntensity
α (α emission)100%
β+ (β+ decay; β+ = ϵ + e+)%

202Fr

AbundanceRadioactive ☢️
Relative Atomic Mass
202.003329637 ± 0.000006476 Da
Mass Number202
G-Factor
1.3 ± 0.016666666666667
Half Life
372 ± 12 ms
Spin3
Quadrupole Moment
Discovery Year1980
Parity+

202Fr Decay Modes
Decay ModeIntensity
α (α emission)100%
β+ (β+ decay; β+ = ϵ + e+)%

203Fr

AbundanceRadioactive ☢️
Relative Atomic Mass
203.000940867 ± 0.000006689 Da
Mass Number203
G-Factor
0.83111111111111 ± 0.0088888888888889
Half Life
550 ± 10 ms
Spin9/2
Quadrupole Moment
-0.47 ± 0.02
Discovery Year1967
Parity-

203Fr Decay Modes
Decay ModeIntensity
α (α emission)100%
β+ (β+ decay; β+ = ϵ + e+)%

204Fr

AbundanceRadioactive ☢️
Relative Atomic Mass
204.000651972 ± 0.000026389 Da
Mass Number204
G-Factor
1.33 ± 0.01
Half Life
1.75 ± 0.26 s
Spin3
Quadrupole Moment
-0.141 ± 0.009
Discovery Year1964
Parity+

204Fr Decay Modes
Decay ModeIntensity
α (α emission)96%
β+ (β+ decay; β+ = ϵ + e+)%

205Fr

AbundanceRadioactive ☢️
Relative Atomic Mass
204.998593854 ± 0.000008399 Da
Mass Number205
G-Factor
0.84444444444444 ± 0.0066666666666667
Half Life
3.9 ± 0.07 s
Spin9/2
Quadrupole Moment
-0.305 ± 0.018
Discovery Year1964
Parity-

205Fr Decay Modes
Decay ModeIntensity
α (α emission)98.5%
β+ (β+ decay; β+ = ϵ + e+)1.5%

206Fr

AbundanceRadioactive ☢️
Relative Atomic Mass
205.998661441 ± 0.000029856 Da
Mass Number206
G-Factor
1.3233333333333 ± 0.016666666666667
Half Life
Spin3
Quadrupole Moment
-0.354 ± 0.009
Discovery Year1964
Parity+

206Fr Decay Modes
Decay ModeIntensity
α (α emission)88.4%
β+ (β+ decay; β+ = ϵ + e+)11.6%

207Fr

AbundanceRadioactive ☢️
Relative Atomic Mass
206.99694145 ± 0.000018847 Da
Mass Number207
G-Factor
0.86 ± 0.0088888888888889
Half Life
14.8 ± 0.1 s
Spin9/2
Quadrupole Moment
-0.24 ± 0.02
Discovery Year1964
Parity-

207Fr Decay Modes
Decay ModeIntensity
α (α emission)95%
β+ (β+ decay; β+ = ϵ + e+)%

208Fr

AbundanceRadioactive ☢️
Relative Atomic Mass
207.997139082 ± 0.000012514 Da
Mass Number208
G-Factor
0.67285714285714 ± 0.0057142857142857
Half Life
59.1 ± 0.3 s
Spin7
Quadrupole Moment
0.052 ± 0.011
Discovery Year1964
Parity+

208Fr Decay Modes
Decay ModeIntensity
α (α emission)89%
β+ (β+ decay; β+ = ϵ + e+)11%

209Fr

AbundanceRadioactive ☢️
Relative Atomic Mass
208.995939701 ± 0.000012349 Da
Mass Number209
G-Factor
0.87333333333333 ± 0.011111111111111
Half Life
50.5 ± 0.7 s
Spin9/2
Quadrupole Moment
-0.26 ± 0.02
Discovery Year1964
Parity-

209Fr Decay Modes
Decay ModeIntensity
α (α emission)89%
β+ (β+ decay; β+ = ϵ + e+)11%

210Fr

AbundanceRadioactive ☢️
Relative Atomic Mass
209.996410596 ± 0.000014407 Da
Mass Number210
G-Factor
0.73 ± 0.0083333333333333
Half Life
3.18 ± 0.06 m
Spin6
Quadrupole Moment
0.21 ± 0.02
Discovery Year1964
Parity+

210Fr Decay Modes
Decay ModeIntensity
α (α emission)71%
β+ (β+ decay; β+ = ϵ + e+)%

211Fr

AbundanceRadioactive ☢️
Relative Atomic Mass
210.995555189 ± 0.000012872 Da
Mass Number211
G-Factor
0.88222222222222 ± 0.011111111111111
Half Life
3.1 ± 0.02 m
Spin9/2
Quadrupole Moment
-0.21 ± 0.02
Discovery Year1964
Parity-

211Fr Decay Modes
Decay ModeIntensity
α (α emission)87%
β+ (β+ decay; β+ = ϵ + e+)13%

212Fr

AbundanceRadioactive ☢️
Relative Atomic Mass
211.99622542 ± 0.000009419 Da
Mass Number212
G-Factor
0.918 ± 0.01
Half Life
20 ± 0.6 m
Spin5
Quadrupole Moment
-0.1 ± 0.002
Discovery Year1950
Parity+

212Fr Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)57%
α (α emission)43%

213Fr

AbundanceRadioactive ☢️
Relative Atomic Mass
212.99618441 ± 0.000005053 Da
Mass Number213
G-Factor
0.88666666666667 ± 0.0022222222222222
Half Life
34.14 ± 0.06 s
Spin9/2
Quadrupole Moment
-0.138 ± 0.003
Discovery Year1964
Parity-

213Fr Decay Modes
Decay ModeIntensity
α (α emission)99.44%
β+ (β+ decay; β+ = ϵ + e+)0.56%

214Fr

AbundanceRadioactive ☢️
Relative Atomic Mass
213.998971193 ± 0.000009145 Da
Mass Number214
G-Factor
0.241 ± 0.016
Half Life
5.51 ± 0.13 ms
Spin1
Quadrupole Moment
Discovery Year1967
Parity-

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

215Fr

AbundanceRadioactive ☢️
Relative Atomic Mass
215.000341534 ± 0.000007585 Da
Mass Number215
G-Factor
Half Life
90 ± 4 ns
Spin9/2
Quadrupole Moment
Discovery Year1970
Parity-

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

216Fr

AbundanceRadioactive ☢️
Relative Atomic Mass
216.003189523 ± 0.00000448 Da
Mass Number216
G-Factor
Half Life
700 ± 20 ns
Spin1
Quadrupole Moment
Discovery Year1970
Parity-

216Fr Decay Modes
Decay ModeIntensity
α (α emission)100%
β+ (β+ decay; β+ = ϵ + e+)%

217Fr

AbundanceRadioactive ☢️
Relative Atomic Mass
217.00463198 ± 0.000007011 Da
Mass Number217
G-Factor
Half Life
22 ± 5 us
Spin9/2
Quadrupole Moment
Discovery Year1968
Parity-

217Fr Decay Modes
Decay ModeIntensity
α (α emission)100%

218Fr

AbundanceRadioactive ☢️
Relative Atomic Mass
218.00757862 ± 0.000004546 Da
Mass Number218
G-Factor
Half Life
1.4 ± 0.5 ms
Spin1
Quadrupole Moment
Discovery Year1949
Parity-

218Fr Decay Modes
Decay ModeIntensity
α (α emission)100%

219Fr

AbundanceRadioactive ☢️
Relative Atomic Mass
219.009250664 ± 0.00000738 Da
Mass Number219
G-Factor
Half Life
22.5 ± 1.7 ms
Spin9/2
Quadrupole Moment
-1.19 ± 0.02
Discovery Year1948
Parity-

219Fr Decay Modes
Decay ModeIntensity
α (α emission)100%

220Fr

AbundanceRadioactive ☢️
Relative Atomic Mass
220.012326789 ± 0.000004324 Da
Mass Number220
G-Factor
-0.66 ± 0.01
Half Life
27.4 ± 0.3 s
Spin1
Quadrupole Moment
0.487 ± 0.008
Discovery Year1948
Parity+

220Fr Decay Modes
Decay ModeIntensity
α (α emission)100%
β (β decay)0.35%

221Fr

AbundanceRadioactive ☢️
Relative Atomic Mass
221.014253714 ± 0.000005245 Da
Mass Number221
G-Factor
0.628 ± 0.008
Half Life
4.801 ± 0.005 m
Spin5/2
Quadrupole Moment
-1.02 ± 0.03
Discovery Year1947
Parity-

221Fr Decay Modes
Decay ModeIntensity
α (α emission)100%
β (β decay)0.0048%
14C8.8%

222Fr

AbundanceRadioactive ☢️
Relative Atomic Mass
222.017582615 ± 0.000008 Da
Mass Number222
G-Factor
0.315 ± 0.005
Half Life
14.2 ± 0.3 m
Spin2
Quadrupole Moment
0.51 ± 0.04
Discovery Year1975
Parity-

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

223Fr

AbundanceRadioactive ☢️
Relative Atomic Mass
223.019734241 ± 0.000002073 Da
Mass Number223
G-Factor
0.77333333333333 ± 0.0066666666666667
Half Life
22 ± 0.07 m
Spin3/2
Quadrupole Moment
1.18 ± 0.02
Discovery Year1939
Parity-

223Fr Decay Modes
Decay ModeIntensity
β (β decay)100%
α (α emission)0.006%

224Fr

AbundanceRadioactive ☢️
Relative Atomic Mass
224.023348096 ± 0.000012 Da
Mass Number224
G-Factor
0.4 ± 0.01
Half Life
3.33 ± 0.1 m
Spin1
Quadrupole Moment
0.523 ± 0.009
Discovery Year1969
Parity-

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

225Fr

AbundanceRadioactive ☢️
Relative Atomic Mass
225.025572466 ± 0.000012847 Da
Mass Number225
G-Factor
0.70666666666667 ± 0.0066666666666667
Half Life
3.95 ± 0.14 m
Spin3/2
Quadrupole Moment
1.33 ± 0.02
Discovery Year1969
Parity-

225Fr Decay Modes
Decay ModeIntensity
β (β decay)100%

226Fr

AbundanceRadioactive ☢️
Relative Atomic Mass
226.029544512 ± 0.000006688 Da
Mass Number226
G-Factor
0.0712 ± 0.0014
Half Life
48.5 ± 0.7 s
Spin1
Quadrupole Moment
-1.37 ± 0.03
Discovery Year1969
Parity-

226Fr Decay Modes
Decay ModeIntensity
β (β decay)100%

227Fr

AbundanceRadioactive ☢️
Relative Atomic Mass
227.031865413 ± 0.000006332 Da
Mass Number227
G-Factor
2.98 ± 0.04
Half Life
2.47 ± 0.03 m
Spin1/2
Quadrupole Moment
0
Discovery Year1972
Parity+

227Fr Decay Modes
Decay ModeIntensity
β (β decay)100%

228Fr

AbundanceRadioactive ☢️
Relative Atomic Mass
228.035839433 ± 0.000007226 Da
Mass Number228
G-Factor
-0.38 ± 0.005
Half Life
38 ± 1 s
Spin2
Quadrupole Moment
2.41 ± 0.06
Discovery Year1972
Parity-

228Fr Decay Modes
Decay ModeIntensity
β (β decay)100%

229Fr

AbundanceRadioactive ☢️
Relative Atomic Mass
229.038291443 ± 0.000005368 Da
Mass Number229
G-Factor
Half Life
50.2 ± 0.4 s
Spin1/2
Quadrupole Moment
0
Discovery Year1975
Parity+

229Fr Decay Modes
Decay ModeIntensity
β (β decay)100%

230Fr

AbundanceRadioactive ☢️
Relative Atomic Mass
230.042390787 ± 0.000007022 Da
Mass Number230
G-Factor
Half Life
19.1 ± 0.5 s
Spin2
Quadrupole Moment
Discovery Year1987
Parity+

230Fr Decay Modes
Decay ModeIntensity
β (β decay)100%

231Fr

AbundanceRadioactive ☢️
Relative Atomic Mass
231.045175353 ± 0.0000083 Da
Mass Number231
G-Factor
Half Life
17.6 ± 0.6 s
Spin1/2
Quadrupole Moment
0
Discovery Year1985
Parity+

231Fr Decay Modes
Decay ModeIntensity
β (β decay)100%

232Fr

AbundanceRadioactive ☢️
Relative Atomic Mass
232.049461219 ± 0.000015 Da
Mass Number232
G-Factor
Half Life
5.5 ± 0.6 s
Spin5
Quadrupole Moment
Discovery Year1990
Parity

232Fr Decay Modes
Decay ModeIntensity
β (β decay)100%
β SF (β-delayed fission)%

233Fr

AbundanceRadioactive ☢️
Relative Atomic Mass
233.052517833 ± 0.000021 Da
Mass Number233
G-Factor
Half Life
900 ± 100 ms
Spin1/2
Quadrupole Moment
0
Discovery Year2010
Parity+

233Fr Decay Modes
Decay ModeIntensity
β (β decay)100%
β n (β-delayed neutron emission)%

History

Francium was discovered in 1939 by Marguerite Perey of the Curie Institute in Paris, France. It was discovered when she was researching the radioactive decay of actinium-227. Marguerite Perey discovered that francium-223 is made naturally when actinium-227 emits an alpha-particle. Francium was named after France

DiscoverersMarguerite Derey
Discovery LocationFrance
Discovery Year1939
Etymology (Name Origin)Named for France, the nation of its discovery.
PronunciationFRAN-si-em (English)
Francium is highly radioactive
Francium was the last element discovered in nature, rather than by synthesis

Uses

Due to its instability and rarity, there are no commercial applications for francium. It has been used for research purposes in the fields of biology and of atomic structure. Its use as a potential diagnostic aid for various cancers has also been explored, but this application has been deemed impractical. Since its isotopes have such short half-lives there are no commercially significant compounds of francium.

Sources

Formed by decay of actinium. Chemical properties similar to cesium. Decays to radium or astatine.

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

Nuclear Screening Constants