Cobalt-51

Properties and data of the isotope ⁵¹Co.

Contents

General data

Name of the isotope:Cobalt-51; Co-51Symbol:⁵¹Co or 5127CoMass number A:51 (= number of nucleons)Atomic number Z:27 (= number of protons)Neutrons N:24Isotopic mass:50.97065(5) u (atomic weight of Cobalt-51)Nuclide mass:50.9558387 u (calculated nuclear mass without electrons)Mass excess:-27.33935 MeVMass defect:0.44858384800001 u (per nucleus)Nuclear binding energy:417.85316291 MeV (per nucleus)
8.19319927 MeV (average binding energy per nucleon)Separation energy:S_N = 17.78(40) MeV (first neutron)
S_P = 0.15(50) MeV (first proton)Half-life:68.8(19) msDecay constant λ:10.074813670929 s^-1Specific activity α:1.213438941279 × 10⁺²³ Bq g^-1
3279564706159.7 Ci g^-1Spin and parity:
(nuclear angular momentum)7/2-Mirror nucleus:Chromium-51Year of discovery:1987

Radioactive Decay

Half-life T_½ = 68.8(19) ms respectively 6.88 × 10^-2 seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
EC β⁺	⁵¹Fe	> 96.2 %	12.86(5) MeV
EC p	⁵⁰Mn	< 3.8 %

Parent Nuclides

Direct parent isotope is: ⁵¹Ni.

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 24) and isobaric (same nucleon number A = 51) with Cobalt-51. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 24	Isobar A = 51
10	³⁴Ne
11	³⁵Na
12	³⁶Mg
13	³⁷Al
14	³⁸Si
15	³⁹P
16	⁴⁰S
17	⁴¹Cl	⁵¹Cl
18	⁴²Ar	⁵¹Ar
19	⁴³K	⁵¹K
20	⁴⁴Ca	⁵¹Ca
21	⁴⁵Sc	⁵¹Sc
22	⁴⁶Ti	⁵¹Ti
23	⁴⁷V	⁵¹V
24	⁴⁸Cr	⁵¹Cr
25	⁴⁹Mn	⁵¹Mn
26	⁵⁰Fe	⁵¹Fe
27	⁵¹Co	⁵¹Co
28	⁵²Ni	⁵¹Ni
29	⁵³Cu
30	⁵⁴Zn