Californium-249m

Properties and data of the isotope ²⁴⁹Cf.

Content

General data

Name of the isotope:Californium-249m; Cf-249mSymbol:²⁴⁹Cf or 24998CfMass number A:249 (= number of nucleons)Atomic number Z:98 (= number of protons)Neutrons N:151Isotopic mass:249.0748505(13) u (atomic weight of Californium-249m)
Excitation energy: 144.98(5) keVNuclide mass:249.0210974 u (calculated nuclear mass without electrons)Mass excess:69.72279 MeVMass defect:2.000404952 u (per nucleus)Nuclear binding energy:1863.36521036 MeV (per nucleus)
7.48339442 MeV (average binding energy per nucleon)Half-life:45(5) μsDecay constant λ:15403.27067911 s^-1Specific activity α:3.725327941097 × 10⁺²⁵ Bq g^-1
1.006845389485 × 10⁺¹⁵ Ci g^-1Spin and parity:
(nuclear angular momentum)5/2+

Nuclear Isomers

Nuclear isomers or excited states with the activation energy in keV related to the ground state.

Nuclear Isomer	Excitation Energy	Half-life	Spin
²⁴⁹Cf		351(2) a	9/2-

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 151) and isobaric (same nucleon number A = 249) with Californium-249m. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 151	Isobar A = 249
92	²⁴²U
93	²⁴⁴Np
94	²⁴⁵Pu
95	²⁴⁶Am	²⁴⁹Am
96	²⁴⁷Cm	²⁴⁹Cm
97	²⁴⁸Bk	²⁴⁹Bk
98	²⁴⁹Cf	²⁴⁹Cf
99	²⁵⁰Es	²⁴⁹Es
100	²⁵¹Fm	²⁴⁹Fm
101	²⁵²Md	²⁴⁹Md
102	²⁵³No
103	²⁵⁴Lr
104	²⁵⁵Rf
105	²⁵⁶Db