Californium (Cf)

Californium is the 98th element in the periodic table and has a symbol of Cf and atomic number of 98. It has an atomic weight of (251) and a mass number of 237. Californium has ninety-eight protons and one hundred thirty-nine neutrons in its nucleus, and ninety-eight electrons in seven shells. It is located in group zero, period seven and block f of the periodic table. Radioactive metallic transuranic element. Belongs to actinoid series. Cf-251 has a half life of about 700 years. Nine isotopes are known. Cf-252 is an intense Neutron source, which makes it an intense Neutron source and gives it a use in Neutron activation analysis and a possible use as a radiation source in medicine. First produced by Glenn T. Seaborg and associates in 1950.

Atomic Number	98
Atomic Weight	251
Mass Number	237

Group
Period	7
Block	f

Protons	98 p⁺
Neutrons	139 n⁰
Electrons	98 e^-

Properties

Physical Properties
Atomic Radius
Molar Volume
Covalent Radius	168 pm 140 pm
Metallic Radius
Ionic Radius	95 pm 82.1 pm 92 pm 112.6 pm
Crystal Radius	109 pm 96.1 pm 106 pm 126.6 pm
Van der Waals Radius	245 pm 331.3 pm
Density	15.1 g/cm³
Energy
Proton Affinity
Electron Affinity
Ionization Energy	6.2817 eV/particle 12 eV/particle 22.4 eV/particle 37.7 eV/particle 51.9 eV/particle 75 eV/particle 91 eV/particle 112.9 eV/particle 133 eV/particle 152 eV/particle 178 eV/particle 202 eV/particle 225 eV/particle 247 eV/particle 265 eV/particle 286 eV/particle 310 eV/particle 334 eV/particle 368 eV/particle 390 eV/particle 536 eV/particle 566 eV/particle 597 eV/particle 630 eV/particle 662 eV/particle 695 eV/particle 744 eV/particle 778 eV/particle 814 eV/particle 847 eV/particle 1,010 eV/particle 1,050 eV/particle 1,090 eV/particle 1,120 eV/particle 1,250 eV/particle 1,300 eV/particle 1,420 eV/particle 1,460 eV/particle 1,620 eV/particle 1,700 eV/particle 1,790 eV/particle 1,880 eV/particle 1,960 eV/particle 2,050 eV/particle 2,130 eV/particle 2,220 eV/particle 2,320 eV/particle 2,410 eV/particle 2,490 eV/particle 2,580 eV/particle 2,670 eV/particle 2,750 eV/particle 3,186 eV/particle 3,261 eV/particle 3,340 eV/particle 3,424 eV/particle 3,503 eV/particle 3,581 eV/particle 3,747 eV/particle 3,828 eV/particle 3,915 eV/particle 3,998 eV/particle 4,329 eV/particle 4,407 eV/particle 4,494 eV/particle 4,570 eV/particle 5,100 eV/particle 5,190 eV/particle 5,430 eV/particle 5,520 eV/particle 8,730 eV/particle 8,900 eV/particle 9,090 eV/particle 9,290 eV/particle 9,480 eV/particle 9,660 eV/particle 10,140 eV/particle 10,330 eV/particle 10,550 eV/particle 10,740 eV/particle 11,300 eV/particle 11,470 eV/particle 11,650 eV/particle 11,820 eV/particle 13,450 eV/particle 13,660 eV/particle 14,080 eV/particle 14,280 eV/particle 29,000 eV/particle 29,500 eV/particle 30,000 eV/particle 30,500 eV/particle 36,500 eV/particle 37,100 eV/particle 37,900 eV/particle 38,443.5 eV/particle 150,579.3 eV/particle 153,124 eV/particle

Heat of Vaporization
Heat of Fusion
Heat of Formation	196 kJ/mol
Electrons
Electron Shells	2, 8, 18, 32, 28, 8, 2

Valence Electrons	2

Electron Configuration	[Rn] 5f¹⁰ 7s²

Oxidation States	2, 3, 4, 5
Electronegativity	0.20369
Electrophilicity
Phases
Phase	Solid
Gas Phase
Boiling Point
Melting Point	1,173.15 K
Critical Pressure
Critical Temperature
Triple Point
Visual
Californium is a Colorless. Cf has a CPK of #ffffff, Jmol of #a136d4, and MOLCAS GV of #a136d4. The Appearance of Element 98 is silvery.
Color	Colorless #ffffff #a136d4 #a136d4
Appearance	silvery
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
The lattice angles of Californium are π/2, π/2, 2 π/3.
Crystal Structure	Simple Hexagonal ()
Lattice Constant
Lattice Angles	π/2, π/2, 2 π/3
Mechanical Properties

Hardness
Bulk Modulus
Shear Modulus
Young Modulus
Poisson Ratio
Speed of Sound
Classification
The Glawe Number of Californium is 42. The Mendeleev Number of Cf is 32. The Pettifor Number of Element 98 is 39. The Goldschmidt Class of Californium (Cf) is synthetic.
Category	Actinides, Actinides
CAS Group
IUPAC Group
Glawe Number	42
Mendeleev Number	32
Pettifor Number	39
Geochemical Class
Goldschmidt Class	synthetic
Other
The Dipole Polarizability of Californium is 122 plus or minus 20 a₀. The Allotropes of Cf is . The Neutron Cross Section of Element 98 is 2900. The Quantum Numbers of Californium (Cf) is 5I8. The Space Group of Californium is 194 (P63/mmc).
Gas Basicity
Dipole Polarizability	122 ± 20 a₀
C6 Dispersion Coefficient
Allotropes
Neutron Cross Section	2,900
Neutron Mass Absorption
Quantum Numbers	5I8
Space Group	194 (P63/mmc)

Isotopes of Californium

Stable Isotopes	0
Unstable Isotopes	20
Radioactive Isotopes	20

²³⁷Cf

Abundance	Radioactive ☢️
Relative Atomic Mass	237.062199272 ± 0.000104506 Da
Mass Number	237
G-Factor
Half Life	0.8 ± 0.2 s
Spin	5/2
Quadrupole Moment
Discovery Year	1995
Parity	+

²³⁷Cf Decay Modes

Decay Mode	Intensity
α (α emission)	70%
SF (spontaneous fission)	30%
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	%

²³⁸Cf

Abundance	Radioactive ☢️
Relative Atomic Mass	238.06149 ± 0.00032 Da
Mass Number	238
G-Factor	0
Half Life	21.1 ± 1.3 ms
Spin	0
Quadrupole Moment	0
Discovery Year	1995
Parity	+

²³⁸Cf Decay Modes

Decay Mode	Intensity
SF (spontaneous fission)	97.5%
α (α emission)	2.5%

²³⁹Cf

Abundance	Radioactive ☢️
Relative Atomic Mass	239.062482 ± 0.000129 Da
Mass Number	239
G-Factor
Half Life	28 ± 2 s
Spin	5/2
Quadrupole Moment
Discovery Year	1981
Parity	+

²³⁹Cf Decay Modes

Decay Mode	Intensity
α (α emission)	65%
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	%

²⁴⁰Cf

Abundance	Radioactive ☢️
Relative Atomic Mass	240.062253447 ± 0.00001936 Da
Mass Number	240
G-Factor	0
Half Life	40.3 ± 0.9 s
Spin	0
Quadrupole Moment	0
Discovery Year	1970
Parity	+

²⁴⁰Cf Decay Modes

Decay Mode	Intensity
α (α emission)	98.5%
SF (spontaneous fission)	1.5%
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	%

²⁴¹Cf

Abundance	Radioactive ☢️
Relative Atomic Mass	241.06369 ± 0.00018 Da
Mass Number	241
G-Factor
Half Life	2.35 ± 0.18 m
Spin	7/2
Quadrupole Moment
Discovery Year	1970
Parity	-

²⁴¹Cf Decay Modes

Decay Mode	Intensity
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	%
α (α emission)	15%

²⁴²Cf

Abundance	Radioactive ☢️
Relative Atomic Mass	242.063754544 ± 0.00001384 Da
Mass Number	242
G-Factor	0
Half Life	3.49 ± 0.15 m
Spin	0
Quadrupole Moment	0
Discovery Year	1967
Parity	+

²⁴²Cf Decay Modes

Decay Mode	Intensity
α (α emission)	61%
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	39%
SF (spontaneous fission)	0.014%

²⁴³Cf

Abundance	Radioactive ☢️
Relative Atomic Mass	243.065475 ± 0.000194 Da
Mass Number	243
G-Factor
Half Life	10.8 ± 0.3 m
Spin	1/2
Quadrupole Moment	0
Discovery Year	1967
Parity	+

²⁴³Cf Decay Modes

Decay Mode	Intensity
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	86%
α (α emission)	14%

²⁴⁴Cf

Abundance	Radioactive ☢️
Relative Atomic Mass	244.065999447 ± 0.000002809 Da
Mass Number	244
G-Factor	0
Half Life	19.5 ± 0.5 m
Spin	0
Quadrupole Moment	0
Discovery Year	1956
Parity	+

²⁴⁴Cf Decay Modes

Decay Mode	Intensity
α (α emission)	75%
ϵ (electron capture)	25%

²⁴⁵Cf

Abundance	Radioactive ☢️
Relative Atomic Mass	245.068046755 ± 0.000002606 Da
Mass Number	245
G-Factor
Half Life	45 ± 1.5 m
Spin	1/2
Quadrupole Moment	0
Discovery Year	1956
Parity	+

²⁴⁵Cf Decay Modes

Decay Mode	Intensity
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	64.7%
α (α emission)	35.3%

²⁴⁶Cf

Abundance	Radioactive ☢️
Relative Atomic Mass	246.068803685 ± 0.000001625 Da
Mass Number	246
G-Factor	0
Half Life	35.7 ± 0.5 h
Spin	0
Quadrupole Moment	0
Discovery Year	1951
Parity	+

²⁴⁶Cf Decay Modes

Decay Mode	Intensity
α (α emission)	100%
SF (spontaneous fission)	2.4%
ϵ (electron capture)	%

²⁴⁷Cf

Abundance	Radioactive ☢️
Relative Atomic Mass	247.070971348 ± 0.00001538 Da
Mass Number	247
G-Factor
Half Life	3.11 ± 0.03 h
Spin	7/2
Quadrupole Moment
Discovery Year	1954
Parity	+

²⁴⁷Cf Decay Modes

Decay Mode	Intensity
ϵ (electron capture)	99.965%
α (α emission)	0.035%

²⁴⁸Cf

Abundance	Radioactive ☢️
Relative Atomic Mass	248.072182905 ± 0.000005497 Da
Mass Number	248
G-Factor	0
Half Life	333.5 ± 2.8 d
Spin	0
Quadrupole Moment	0
Discovery Year	1954
Parity	+

²⁴⁸Cf Decay Modes

Decay Mode	Intensity
α (α emission)	100%
SF (spontaneous fission)	0.0029%

²⁴⁹Cf

Abundance	Radioactive ☢️
Relative Atomic Mass	249.074850428 ± 0.000001269 Da
Mass Number	249
G-Factor
Half Life	351 ± 2 y
Spin	9/2
Quadrupole Moment
Discovery Year	1954
Parity	-

²⁴⁹Cf Decay Modes

Decay Mode	Intensity
α (α emission)	100%
SF (spontaneous fission)	5%

²⁵⁰Cf

Abundance	Radioactive ☢️
Relative Atomic Mass	250.076404494 ± 0.00000165 Da
Mass Number	250
G-Factor	0
Half Life	13.08 ± 0.09 y
Spin	0
Quadrupole Moment	0
Discovery Year	1954
Parity	+

²⁵⁰Cf Decay Modes

Decay Mode	Intensity
α (α emission)	99.923%
SF (spontaneous fission)	0.077%

²⁵¹Cf

Abundance	Radioactive ☢️
Relative Atomic Mass	251.079587171 ± 0.000004187 Da
Mass Number	251
G-Factor
Half Life	898 ± 44 y
Spin	1/2
Quadrupole Moment	0
Discovery Year	1954
Parity	+

²⁵¹Cf Decay Modes

Decay Mode	Intensity
α (α emission)	100%
SF (spontaneous fission)	%

²⁵²Cf

Abundance	Radioactive ☢️
Relative Atomic Mass	252.081626507 ± 0.000002531 Da
Mass Number	252
G-Factor	0
Half Life	2.645 ± 0.008 y
Spin	0
Quadrupole Moment	0
Discovery Year	1954
Parity	+

²⁵²Cf Decay Modes

Decay Mode	Intensity
α (α emission)	96.8972%
SF (spontaneous fission)	3.1028%

²⁵³Cf

Abundance	Radioactive ☢️
Relative Atomic Mass	253.085133723 ± 0.00000457 Da
Mass Number	253
G-Factor
Half Life	17.81 ± 0.08 d
Spin	7/2
Quadrupole Moment
Discovery Year	1954
Parity	+

²⁵³Cf Decay Modes

Decay Mode	Intensity
β⁻ (β⁻ decay)	99.69%
α (α emission)	0.31%

²⁵⁴Cf

Abundance	Radioactive ☢️
Relative Atomic Mass	254.087323575 ± 0.000012304 Da
Mass Number	254
G-Factor	0
Half Life	60.5 ± 0.2 d
Spin	0
Quadrupole Moment	0
Discovery Year	1955
Parity	+

²⁵⁴Cf Decay Modes

Decay Mode	Intensity
SF (spontaneous fission)	99.69%
α (α emission)	0.31%
2β⁻ (double β⁻ decay)	%

²⁵⁵Cf

Abundance	Radioactive ☢️
Relative Atomic Mass	255.091046 ± 0.000215 Da
Mass Number	255
G-Factor
Half Life	85 ± 18 m
Spin	7/2
Quadrupole Moment
Discovery Year	1981
Parity	+

²⁵⁵Cf Decay Modes

Decay Mode	Intensity
β⁻ (β⁻ decay)	100%
SF (spontaneous fission)	%
α (α emission)	%

²⁵⁶Cf

Abundance	Radioactive ☢️
Relative Atomic Mass	256.093442 ± 0.000338 Da
Mass Number	256
G-Factor	0
Half Life	12.3 ± 1.2 m
Spin	0
Quadrupole Moment	0
Discovery Year	1980
Parity	+

²⁵⁶Cf Decay Modes

Decay Mode	Intensity
SF (spontaneous fission)	100%
α (α emission)	%
2β⁻ (double β⁻ decay)	%

History

Californium was discovered by Stanley G. Thompson, Kenneth Street, Jr., Albert Ghiorso and Glenn T. Seaborg in 1950 at the University of California, Berkeley. It was produced by the bombardment of curium with alpha particles. Californium was isolated in macro quantities for the first time by Burris Cunningham and Stanley Thompson in 1958. Named after California and the University of California

Discoverers	G.T.Seaborg, S.G.Tompson, A.Ghiorso, K.Street Jr.
Discovery Location	United States
Discovery Year	1950
Etymology (Name Origin)	Named after the state and University of California.
Pronunciation	kal-eh-FOR-ni-em (English)

Californium is harmful due to its radioactivity

Californium is produced in nuclear reactors and particle accelerators

Uses

Californium is used as a portable neutron source for discovery of metals such as gold or silver by on-the-spot activation analysis. Neutrons from californium are employed as a treatment of certain cervical and brain cancers where other radiation therapy is ineffective. Neutron moisture gauges use californium-252 to find water and petroleum layers in oil wells. It has no significant commercial applications.

Sources

Made by bombarding curium with helium ions.

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

Californium on ChemicalAid

Art & Architecture Thesaurus ID	300380331
Australian Educational Vocabulary ID	scot/3074
CAS Registry Number	7440-71-3
ChEBI ID	33392
ChemSpider ID	22433
DSSTOX compound identifier	DTXCID00147883
DSSTox substance ID	DTXSID00225392
Den Store Danske ID	californium
Encyclopædia Britannica Online ID	science/californium
Encyclopædia Universalis ID	californium
Freebase ID	/m/025tkv8
French Vikidia ID	Californium
GND ID	4147208-1
Gran Enciclopèdia Catalana ID	0087352
Gran Enciclopèdia Catalana ID	0017254
Great Russian Encyclopedia Online ID	2036031
InChI	InChI=1S/Cf
InChIKey	HGLDOAKPQXAFKI-UHFFFAOYSA-N
KBpedia ID	Californium
Library of Congress authority ID	sh89004338
MeSH descriptor ID	D002142
NALT ID	3198
NDL Authority ID	00565048
National Library of Israel J9U ID	987007553750405171
OmegaWiki Defined Meaning	156905
OpenAlex ID	C547234621
PubChem CID	23997
Römpp online ID	RD-03-00207
Store norske leksikon ID	californium
Treccani ID	californio
UNII	975X05H15A
USGS Thesaurus ID	1419
WordNet 3.1 Synset ID	14657215-n

Californium (Cf)

Properties

Isotopes of Californium

237Cf

237Cf Decay Modes

238Cf

238Cf Decay Modes

239Cf

239Cf Decay Modes

240Cf

240Cf Decay Modes

241Cf

241Cf Decay Modes

242Cf

242Cf Decay Modes

243Cf

243Cf Decay Modes

244Cf

244Cf Decay Modes

245Cf

245Cf Decay Modes

246Cf

246Cf Decay Modes

247Cf

247Cf Decay Modes

248Cf

248Cf Decay Modes

249Cf

249Cf Decay Modes

250Cf

250Cf Decay Modes

251Cf

251Cf Decay Modes

252Cf

252Cf Decay Modes

253Cf

253Cf Decay Modes

254Cf

254Cf Decay Modes

255Cf

255Cf Decay Modes

256Cf

256Cf Decay Modes