Rutherfordium-256

Properties and data of the isotope ²⁵⁶Rf.

Contents

General Data

Radioactive Decay

Parent Nuclides

Isotones und Isobares

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

General data

Name of the isotope:Rutherfordium-256; Rf-256Symbol:²⁵⁶Rf or 256104RfMass number A:256 (= number of nucleons)Atomic number Z:104 (= number of protons)Neutrons N:152Nucleon pairing (Z - N):even - evenNuclear ratio (N/Z ratio):1.4615384615385 (= neutron-proton ratio)Neutron excess (N-Z):48Isotopic mass:256.101152(19) u (atomic weight of Rutherfordium-256)Nuclide mass:256.0441086 u (calculated nuclear mass without electrons)Mass excess:94.22248 MeVMass defect:2.02971856 u (per nucleus)Nuclear binding energy:1890.67066033 MeV (per nucleus)
7.38543227 MeV (average binding energy per nucleon)Separation energy:S_N = 8.18(12) MeV (first neutron)
S_P = 3.014(25) MeV (first proton)Half-life:6.67(10) msDecay constant λ:103.92011702548 s^-1Specific activity α:2.444615558236 × 10⁺²³ Bq g^-1
6607069076314.9 Ci g^-1Spin and parity:
(nuclear angular momentum)0+Year of discovery:1975

Radioactive Decay

Half-life T_½ = 6.67(10) ms respectively 6.67 × 10^-3 seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
α	²⁵²No	0.32(17) %	8.926(15) MeV
SZ	div	99.68(17) %

Parent Nuclides

Direct parent isotope is: ²⁶⁰Sg.

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
^256m1Rf	1120 keV	25(2) μs	(5-)
^256m2Rf	1400 keV	17(2) μs	(8-)
^256m3Rf	2200 keV	27(5) μs

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 152) and isobaric (same nucleon number A = 256) with Rutherfordium-256. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 152	Isobar A = 256
94	²⁴⁶Pu
95	²⁴⁷Am
96	²⁴⁸Cm
97	²⁴⁹Bk
98	²⁵⁰Cf	²⁵⁶Cf
99	²⁵¹Es	²⁵⁶Es
100	²⁵²Fm	²⁵⁶Fm
101	²⁵³Md	²⁵⁶Md
102	²⁵⁴No	²⁵⁶No
103	²⁵⁵Lr	²⁵⁶Lr
104	²⁵⁶Rf	²⁵⁶Rf
105	²⁵⁷Db	²⁵⁶Db
106	²⁵⁸Sg