Cobalt-56

Properties and data of the isotope ⁵⁶Co.

Contents

General data

Name of the isotope:Cobalt-56; Co-56Symbol:⁵⁶Co or 5627CoMass number A:56 (= number of nucleons)Atomic number Z:27 (= number of protons)Neutrons N:29Isotopic mass:55.9398380(5) u (atomic weight of Cobalt-56)Nuclide mass:55.9250267 u (calculated nuclear mass without electrons)Mass excess:-56.04054 MeVMass defect:0.522720428 u (per nucleus)Nuclear binding energy:486.91094236 MeV (per nucleus)
8.69483826 MeV (average binding energy per nucleon)Separation energy:S_N = 10.0818(5) MeV (first neutron)
S_P = 5.8481(4) MeV (first proton)Half-life:77.236(26) dDecay constant λ:1.038704336324 × 10^-7 s^-1Specific activity α:1.137313422758 × 10⁺¹⁵ Bq g^-1
30738.200615103 Ci g^-1Spin and parity:
(nuclear angular momentum)4+Magnetic dipole moment:μ(μ_N) = 3.85(1)Quadrupole moment Q:+0.25(9) barn (100 fm²)Nuclear g-factor:g_l = 0.9625Mirror nucleus:Copper-56Year of discovery:1941

Radioactive Decay

Half-life T_½ = 77.236(26) d respectively 6.6731904 × 10⁶ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
EC β⁺	⁵⁶Fe	100 %	4.5666(5) MeV

Parent Nuclides

Direct parent isotope is: ⁵⁶Ni.

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 29) and isobaric (same nucleon number A = 56) with Cobalt-56. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 29	Isobar A = 56
13	⁴²Al
14	⁴³Si
15	⁴⁴P
16	⁴⁵S
17	⁴⁶Cl
18	⁴⁷Ar
19	⁴⁸K	⁵⁶K
20	⁴⁹Ca	⁵⁶Ca
21	⁵⁰Sc	⁵⁶Sc
22	⁵¹Ti	⁵⁶Ti
23	⁵²V	⁵⁶V
24	⁵³Cr	⁵⁶Cr
25	⁵⁴Mn	⁵⁶Mn
26	⁵⁵Fe	⁵⁶Fe
27	⁵⁶Co	⁵⁶Co
28	⁵⁷Ni	⁵⁶Ni
29	⁵⁸Cu	⁵⁶Cu
30	⁵⁹Zn	⁵⁶Zn
31	⁶⁰Ga
32	⁶¹Ge
33	⁶²As
34	⁶³Se