Cobalt-59
Properties and data of the isotope 59Co.
Cobalt-59 is the only stable, naturally occurring isotope of the chemical element cobalt, which has 32 neutrons in its atomic nucleus in addition to the element-specific 27 protons; the sum of the number of these atomic nucleus building blocks results in a mass number of 59.
The first detection of the nuclide Co-59, which was carried out by mass spectrometry, was reported in 1923 [1].
See also: List of individual Cobalt isotopes (and general data sources).
General data
Name of the isotope:Cobalt-59; Co-59Symbol:59Co or 5927CoMass number A:59 (= number of nucleons)Atomic number Z:27 (= number of protons)Neutrons N:32Nucleon pairing (Z - N):odd - evenNuclear ratio (N/Z ratio):1.1851851851852 (= neutron-proton ratio)Neutron excess (N-Z):5Isotopic mass:58.9331935(4) u (atomic weight of Cobalt-59)Nuclide mass:58.9183822 u (calculated nuclear mass without electrons)Mass excess:-62.22985 MeVMass defect:0.55535967599999 u (per nucleus)Nuclear binding energy:517.31420604 MeV (per nucleus)
8.76803739 MeV (average binding energy per nucleon)Separation energy:SN = 10.4539(11) MeV (first neutron)
SP = 7.3635(4) MeV (first proton)Half-life:stableSpin and parity:
(nuclear angular momentum)7/2-Magnetic dipole moment:μ(μN) = +4.627(9)Charge radius:3.7875(21) femtometer fmMirror nucleus:Germanium-59Year of discovery:1923
Parent Nuclides
Direct parent isotopes are: 59Ni, 59Fe.
Occurrence
Comparison of the natural Cobalt isotopes including isotopic abundance (mole fraction of the isotope mixture in percent):
| | Atomic Mass ma | Quantity | Half-life | Spin |
|---|
Cobalt
Isotopic mixture | 58.933194 u | 100 % | | |
| Isotope 59Co | 58.9331935(4) u | 100 % | stable | 7/2- |
NMR data
Nuclear magnetic properties and parameters of the NMR active Nuclide 59Co
Isotope:59Co-NMRQuantity:100 %Spin:7/2-Nuclearmagnetic moment
μ/μN:+4.627(9)Gyromagnetic ratio γ:6.317 · 107 rad T-1 s-1
10.05382 MHz T-1Nuclear g-factor:gl = 1.322Quadrupole moment Q:+0.42(3) barn (100 fm2)Line width parameter (factor):l = 240 fm4Resonance frequency:v0 = 10.077 MHz at 1 TRelative Sensitivity:[related to 1H = 1.000]:
0.27841 (H0 = const.)
4.9703 (v0 = const.)
0.278 (at natural abundance)
relative receptivity as compared to 13C:
1640 (at natural abundance)Reference compound:
(conditions)0.56 molar solution of potassium hexacyanocobaltate(III) K3[Co(CN)6] in Deuterium Oxide D2O.Frequency ratio:Ξ(59Co) = 23.727074 % [based on the reference substance]Chemical shift range:ca. 18000 ppm [-4000 to +14000]
Isotones and Isobars
The following table shows the atomic nuclei that are isotonic (same neutron number N = 32) and isobaric (same nucleon number A = 59) with Cobalt-59. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.
| Z | Isotone N = 32 | Isobar A = 59 |
|---|
| 15 | 47P | |
| 16 | 48S | |
| 17 | 49Cl | |
| 18 | 50Ar | |
| 19 | 51K | 59K |
| 20 | 52Ca | |
| 21 | 53Sc | 59Sc |
| 22 | 54Ti | 59Ti |
| 23 | 55V | 59V |
| 24 | 56Cr | 59Cr |
| 25 | 57Mn | 59Mn |
| 26 | 58Fe | 59Fe |
| 27 | 59Co | 59Co |
| 28 | 60Ni | 59Ni |
| 29 | 61Cu | 59Cu |
| 30 | 62Zn | 59Zn |
| 31 | 63Ga | 59Ga |
| 32 | 64Ge | 59Ge |
| 33 | 65As | |
| 34 | 66Se | |
| 35 | 67Br | |
| 36 | 68Kr | |
External data and identifiers
Literature and References
[1] - F. W. Aston:
Further Determinations of the Constitution of the Elements by the Method of Accelerated Anode Rays.
In: Nature, 112, (1923), DOI 10.1038/112449a0.
Last update: 2026-01-16
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