Rutherfordium-253m

Properties and data of the isotope ^253mRf.

Contents

See also: List of individual Rutherfordium isotopes (and general data sources).

General data

Name of the isotope:Rutherfordium-253m; Rf-253mOther names:Rutherfordium-253m1Symbol:^253mRf or 253m104RfMass number A:253 (= number of nucleons)Atomic number Z:104 (= number of protons)Neutrons N:149Nucleon pairing (Z - N):even - oddNuclear ratio (N/Z ratio):1.4326923076923 (= neutron-proton ratio)Neutron excess (N-Z):45Excitation energy:+y keVIsotopic mass:253.10044(44) u (atomic weight of Rutherfordium-253m)Nuclide mass:253.0433966 u (calculated nuclear mass without electrons)Mass excess:93.55926 MeVMass defect:2.004435812 u (per nucleus)Nuclear binding energy:1867.11993226 MeV (per nucleus)
7.37992068 MeV (average binding energy per nucleon)Half-life:52.8(44) μsDecay constant λ:13127.787510605 s^-1Specific activity α:3.124797848544 × 10⁺²⁵ Bq g^-1
8.445399590661 × 10⁺¹⁴ Ci g^-1Spin and parity:
(nuclear angular momentum)(7/2+)Year of discovery:1995

Radioactive Decay

Half-life T_½ = 52.8(44) μs respectively 5.28 × 10^-5 seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
α		?
SZ		< 100 %

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
²⁵³Rf		9.9(12) ms	(1/2+)

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 149) and isobaric (same nucleon number A = 253) with Rutherfordium-253m. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 149	Isobar A = 253
91	²⁴⁰Pa
92	²⁴¹U
93	²⁴²Np
94	²⁴³Pu
95	²⁴⁴Am
96	²⁴⁵Cm
97	²⁴⁶Bk	²⁵³Bk
98	²⁴⁷Cf	²⁵³Cf
99	²⁴⁸Es	²⁵³Es
100	²⁴⁹Fm	²⁵³Fm
101	²⁵⁰Md	²⁵³Md
102	²⁵¹No	²⁵³No
103	²⁵²Lr	²⁵³Lr
104	²⁵³Rf	²⁵³Rf