Berkelium

Berkelium (Bk)

Radioactive metallic transuranic element. Belongs to actinoid series. Eight known isotopes, the most common Bk-247, has a half-life of 1.4*10^3 years. First produced by Glenn T. Seaborg and associates in 1949 by bombarding americium-241 with alpha particles.
Atomic Number97
Atomic Weight247
Mass Number233
Group
Period7
Blockf
Protons97 p+
Neutrons136 n0
Electrons97 e-
Berkelium metal.jpg Animated Bohr Model of Bk (Berkelium) Enhanced Bohr Model of Bk (Berkelium) Bohr Model: Bk (Berkelium) Orbital Diagram of Bk (Berkelium)

Properties

Atomic Radius
Molar Volume
Covalent Radius
168 pm
Metallic Radius
Ionic Radius
96 pm
Crystal Radius
110 pm
Van der Waals Radius
244 pm
Density
14.78 g/cm³
Energy
Proton Affinity
Electron Affinity
Ionization Energy
Heat of Vaporization
Heat of Fusion
Heat of Formation
310 kJ/mol
Electrons
Electron Shells2, 8, 18, 32, 27, 8, 2
Valence Electrons4
Electron Configuration[Rn] 5f9 7s2
Oxidation States2, 3, 4, 5
Electronegativity
Electrophilicity
Phases
PhaseSolid
Gas Phase
Boiling Point
Melting Point
1,259.15 K
Critical Pressure
Critical Temperature
Triple Point
Visual
Color
Colorless
Appearancesilvery
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 StructureSimple Hexagonal ()
Lattice Constant
Lattice Anglesπ/2, π/2, 2 π/3
Mechanical Properties
Hardness
Bulk Modulus
Shear Modulus
Young Modulus
Poisson Ratio
Speed of Sound
Classification
CategoryActinides, Actinides
CAS Group
IUPAC Group
Glawe Number41
Mendeleev Number30
Pettifor Number40
Geochemical Class
Goldschmidt Classsynthetic
Other
Gas Basicity
Dipole Polarizability
125 ± 25 a₀
C6 Dispersion Coefficient
Allotropes
Neutron Cross Section
710
Neutron Mass Absorption
Quantum Numbers6H15/2
Space Group194 (P63/mmc)

Isotopes of Berkelium

Stable Isotopes0
Unstable Isotopes22
Radioactive Isotopes22

233Bk

AbundanceRadioactive ☢️
Relative Atomic Mass
233.056652 ± 0.00025 Da
Mass Number233
G-Factor
Half Life
40 ± 30 s
Spin3/2
Quadrupole Moment
Discovery Year2015
Parity-

233Bk Decay Modes
Decay ModeIntensity
α (α emission)82%
β+ (β+ decay; β+ = ϵ + e+)%

234Bk

AbundanceRadioactive ☢️
Relative Atomic Mass
234.057322 ± 0.000164 Da
Mass Number234
G-Factor
Half Life
20 ± 5 s
Spin3
Quadrupole Moment
Discovery Year2003
Parity-

234Bk Decay Modes
Decay ModeIntensity
α (α emission)80%
β+ (β+ decay; β+ = ϵ + e+)20%

235Bk

AbundanceRadioactive ☢️
Relative Atomic Mass
235.056651 ± 0.00043 Da
Mass Number235
G-Factor
Half Life
Spin3/2
Quadrupole Moment
Discovery Year
Parity-

235Bk Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)%
α (α emission)%

236Bk

AbundanceRadioactive ☢️
Relative Atomic Mass
236.057479 ± 0.000387 Da
Mass Number236
G-Factor
Half Life
26 ± 10 s
Spin4
Quadrupole Moment
Discovery Year2017
Parity+

236Bk Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%
α (α emission)%
β+ SF (β+-delayed fission)0.04%

237Bk

AbundanceRadioactive ☢️
Relative Atomic Mass
237.057123 ± 0.000247 Da
Mass Number237
G-Factor
Half Life
Spin3/2
Quadrupole Moment
Discovery Year
Parity-

237Bk Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)%
α (α emission)%

238Bk

AbundanceRadioactive ☢️
Relative Atomic Mass
238.058204 ± 0.000275 Da
Mass Number238
G-Factor
Half Life
2.4 ± 0.08 m
Spin1
Quadrupole Moment
Discovery Year1994
Parity

238Bk Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%
α (α emission)%
β+ SF (β+-delayed fission)0.048%

239Bk

AbundanceRadioactive ☢️
Relative Atomic Mass
239.058239 ± 0.000222 Da
Mass Number239
G-Factor
Half Life
Spin7/2
Quadrupole Moment
Discovery Year1989
Parity+

239Bk Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%
α (α emission)0.01%
SF (spontaneous fission)0.01%

240Bk

AbundanceRadioactive ☢️
Relative Atomic Mass
240.059758 ± 0.000161 Da
Mass Number240
G-Factor
Half Life
4.8 ± 0.8 m
Spin7
Quadrupole Moment
Discovery Year1980
Parity-

240Bk Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)%
α (α emission)%
β+ SF (β+-delayed fission)0.002%

241Bk

AbundanceRadioactive ☢️
Relative Atomic Mass
241.060098 ± 0.000178 Da
Mass Number241
G-Factor
Half Life
4.6 ± 0.4 m
Spin7/2
Quadrupole Moment
Discovery Year2003
Parity+

241Bk Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)%
α (α emission)%

242Bk

AbundanceRadioactive ☢️
Relative Atomic Mass
242.061999 ± 0.000144 Da
Mass Number242
G-Factor
Half Life
7 ± 1.3 m
Spin3
Quadrupole Moment
Discovery Year1972
Parity+

242Bk Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%
β+ SF (β+-delayed fission)3%
α (α emission)%

243Bk

AbundanceRadioactive ☢️
Relative Atomic Mass
243.063005905 ± 0.000004856 Da
Mass Number243
G-Factor
Half Life
4.6 ± 0.2 h
Spin3/2
Quadrupole Moment
Discovery Year1950
Parity-

243Bk Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%
α (α emission)0.15%

244Bk

AbundanceRadioactive ☢️
Relative Atomic Mass
244.065178969 ± 0.000015457 Da
Mass Number244
G-Factor
Half Life
5.02 ± 0.03 h
Spin4
Quadrupole Moment
Discovery Year1972
Parity-

244Bk Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)%
α (α emission)0.006%

245Bk

AbundanceRadioactive ☢️
Relative Atomic Mass
245.066359814 ± 0.000001923 Da
Mass Number245
G-Factor
Half Life
4.95 ± 0.03 d
Spin3/2
Quadrupole Moment
Discovery Year1951
Parity-

245Bk Decay Modes
Decay ModeIntensity
ϵ (electron capture)99.88%
α (α emission)0.12%

246Bk

AbundanceRadioactive ☢️
Relative Atomic Mass
246.0686713 ± 0.000064433 Da
Mass Number246
G-Factor
Half Life
1.8 ± 0.02 d
Spin2
Quadrupole Moment
Discovery Year1954
Parity

246Bk Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%
α (α emission)%

247Bk

AbundanceRadioactive ☢️
Relative Atomic Mass
247.070305889 ± 0.00000557 Da
Mass Number247
G-Factor
Half Life
1.38 ± 0.25 ky
Spin3/2
Quadrupole Moment
Discovery Year1965
Parity-

247Bk Decay Modes
Decay ModeIntensity
α (α emission)100%
SF (spontaneous fission)%

248Bk

AbundanceRadioactive ☢️
Relative Atomic Mass
248.073141689 ± 0.000053739 Da
Mass Number248
G-Factor
Half Life
Spin6
Quadrupole Moment
Discovery Year1956
Parity+

248Bk Decay Modes
Decay ModeIntensity
α (α emission)%
ϵ (electron capture)%

249Bk

AbundanceRadioactive ☢️
Relative Atomic Mass
249.074983118 ± 0.000001339 Da
Mass Number249
G-Factor
0.57142857142857 ± 0.11428571428571
Half Life
327.2 ± 0.3 d
Spin7/2
Quadrupole Moment
Discovery Year1954
Parity+

249Bk Decay Modes
Decay ModeIntensity
β (β decay)100%
α (α emission)0.00145%
SF (spontaneous fission)47%

250Bk

AbundanceRadioactive ☢️
Relative Atomic Mass
250.078317195 ± 0.00000311 Da
Mass Number250
G-Factor
Half Life
3.212 ± 0.005 h
Spin2
Quadrupole Moment
Discovery Year1954
Parity-

250Bk Decay Modes
Decay ModeIntensity
β (β decay)100%

251Bk

AbundanceRadioactive ☢️
Relative Atomic Mass
251.080760555 ± 0.000011523 Da
Mass Number251
G-Factor
Half Life
55.6 ± 1.1 m
Spin3/2
Quadrupole Moment
Discovery Year1967
Parity-

251Bk Decay Modes
Decay ModeIntensity
β (β decay)100%

252Bk

AbundanceRadioactive ☢️
Relative Atomic Mass
252.08431 ± 0.000215 Da
Mass Number252
G-Factor
Half Life
1.8 ± 0.5 m
Spin
Quadrupole Moment
Discovery Year1988
Parity

252Bk Decay Modes
Decay ModeIntensity
β (β decay)%
α (α emission)%

253Bk

AbundanceRadioactive ☢️
Relative Atomic Mass
253.08688 ± 0.000385 Da
Mass Number253
G-Factor
Half Life
Spin3/2
Quadrupole Moment
Discovery Year1991
Parity-

253Bk Decay Modes
Decay ModeIntensity
β (β decay)%

254Bk

AbundanceRadioactive ☢️
Relative Atomic Mass
254.0906 ± 0.00032 Da
Mass Number254
G-Factor
Half Life
Spin
Quadrupole Moment
Discovery Year
Parity

254Bk Decay Modes
Decay ModeIntensity
β (β decay)%

History

Berkelium was discovered by Glenn T. Seaborg, Albert Ghiorso and Stanley G. Thompson in 1949 at the University of California, Berkeley. It was produced by the bombardment of americium with alpha particles. Berkelium was isolated in greater quantities for the first time by Burris Cunningham and Stanley Thompson in 1958. Named after Berkeley, California, the city of its discovery

DiscoverersG.T.Seaborg, S.G.Tompson, A.Ghiorso
Discovery LocationUnited States
Discovery Year1949
Etymology (Name Origin)Named after Berkeley, California the city of its discovery.
PronunciationBURK-li-em (English)
Berkelium is harmful due to its radioactivity
Just over one gram of berkelium has been produced in the United States since 1967

Uses

Berkelium is mainly used for scientific research purposes. Berkelium-249 is a common target nuclide to prepare still heavier transuranic elements and transactinides, such as lawrencium, rutherfordium and bohrium. It is also useful as a source of the isotope californium-249. It has no significant commercial applications.

Sources

Some compounds have been made and studied. Made by bombarding americium with alpha particles.

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

Nuclear Screening Constants