Cobalt-57

Properties and data of the isotope ⁵⁷Co.

Contents

General Data

Radioactive Decay

Parent Nuclides

Isotones und Isobares

Literature

Cobalt-57 is a radioisotope of the chemical element cobalt with the mass number 57. The atomic nucleus of the nuclide consists of 30 neutrons and 27 protons.

The radioactive isotope ⁵⁷ is used to produce standards for the calibration of radiometric devices and medical gamma cameras. Vitamin B12 labelled with Co-57 is used in diagnostic kits, e.g. to examine iron deficiency anemia; see also Schilling test.

General data

Name of the isotope:Cobalt-57; Co-57Symbol:⁵⁷Co or 5727CoMass number A:57 (= number of nucleons)Atomic number Z:27 (= number of protons)Neutrons N:30Isotopic mass:56.9362898(6) u (atomic weight of Cobalt-57)Nuclide mass:56.9214785 u (calculated nuclear mass without electrons)Mass excess:-59.34567 MeVMass defect:0.534933544 u (per nucleus)Nuclear binding energy:498.28738663 MeV (per nucleus)
8.74188398 MeV (average binding energy per nucleon)Separation energy:S_N = 11.3765(6) MeV (first neutron)
S_P = 6.0275(4) MeV (first proton)Half-life:271.74(6) dDecay constant λ:2.952284099520 × 10^-8 s^-1Specific activity α:3.174834054618 × 10⁺¹⁴ Bq g^-1
8580.6325800495 Ci g^-1Spin and parity:
(nuclear angular momentum)7/2-Isobaric spin: 3/2Magnetic dipole moment:μ(μ_N) = +4.720(10)Quadrupole moment Q:+0.52(9) barn (100 fm²)Nuclear g-factor:g_l = 1.3485714285714Mirror nucleus:Zinc-57Year of discovery:1941

Radioactive Decay

Half-life T_½ = 271.74(6) d respectively 2.3478336 × 10⁷ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
EC	⁵⁷Fe	100 %	0.8364(6) MeV	0.12206065(12) MeV 85.60(17) %

Parent Nuclides

Direct parent isotope is: ⁵⁷Ni.

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 30) and isobaric (same nucleon number A = 57) with Cobalt-57. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 30	Isobar A = 57
13	⁴³Al
14	⁴⁴Si
15	⁴⁵P
16	⁴⁶S
17	⁴⁷Cl
18	⁴⁸Ar
19	⁴⁹K
20	⁵⁰Ca	⁵⁷Ca
21	⁵¹Sc	⁵⁷Sc
22	⁵²Ti	⁵⁷Ti
23	⁵³V	⁵⁷V
24	⁵⁴Cr	⁵⁷Cr
25	⁵⁵Mn	⁵⁷Mn
26	⁵⁶Fe	⁵⁷Fe
27	⁵⁷Co	⁵⁷Co
28	⁵⁸Ni	⁵⁷Ni
29	⁵⁹Cu	⁵⁷Cu
30	⁶⁰Zn	⁵⁷Zn
31	⁶¹Ga
32	⁶²Ge
33	⁶³As
34	⁶⁴Se

External data and identifiers

CAS:13981-50-5InChI Key:GUTLYIVDDKVIGB-YPZZEJLDSA-NSMILES:[57Co]PubChem:ID 104851Adopted Levels, Gammas:NuDat 57Co

Literature and References

[1] - Jun Young Lee et al.:
Production of cobalt-57 for industrial and medical applications in RFT-30 cyclotron facility.
In: Journal of Radioanalytical and Nuclear Chemistry, 332, 5097–5103, (2023), DOI 10.1007/s10967-023-08978-2.