Rutherfordium-257
Properties and data of the isotope 257Rf.
See also: list of Rutherfordium isotopes.
General data
Name of the isotope:Rutherfordium-257; Rf-257Symbol:257Rf or 257104RfMass number A:257 (= number of nucleons)Atomic number Z:104 (= number of protons)Neutrons N:153Isotopic mass:257.102918(12) u (atomic weight of Rutherfordium-257)Nuclide mass:257.0458746 u (calculated nuclear mass without electrons)Mass excess:95.8675 MeVMass defect:2.036617476 u (per nucleus)Nuclear binding energy:1897.09695919 MeV (per nucleus)
7.38170023 MeV (average binding energy per nucleon)Separation energy:SN = 6.427(21) MeV (first neutron)
SP = 3.17(8) MeV (first proton)Half-life:4.4(3) sDecay constant λ:0.15753345012726 s-1Specific activity α:3.691395435090 × 10+20 Bq g-1
9976744419.1627 Ci g-1Spin and parity:
(nuclear angular momentum)(1/2+)Year of discovery:1969
Radioactive Decay
Half-life T½ = 4.4(3) s.
Decay mode | Daughter | Probability | Decay energy | γ energy (intensity) |
---|
EE | 257Lr | 19.4(14) % | 3.20(5) MeV | |
SZ | div. | 1.3(3) % | | |
α | 253No | 79.3(14) % | 9,083(8) MeV | |
Parent Nuclides
Direct parent isotope is: 261Sg.
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 |
---|
257mRf | 75 keV | 4.1(4) s | (11/2-) |
Isotones and Isobars
The following table shows the atomic nuclei that are isotonic (same neutron number N = 153) and isobaric (same nucleon number A = 257) with Rutherfordium-257. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.
OZ | Isotone N = 153 | Isobar A = 257 |
94 | 247Pu | |
95 | 248Am | |
96 | 249Cm | |
97 | 250Bk | |
98 | 251Cf | |
99 | 252Es | 257Es |
100 | 253Fm | 257Fm |
101 | 254Md | 257Md |
102 | 255No | 257No |
103 | 256Lr | 257Lr |
104 | 257Rf | 257Rf |
105 | 258Db | 257Db |
106 | 259Sg | |
107 | 260Bh | |
External data and identifiers
Last update: 2020-11-04
Perma link: https://www.chemlin.org/isotope/rutherfordium-257
© 1996 - 2024 ChemLin