Iron-51

Properties and data of the isotope ⁵¹Fe.

Contents

General data

Name of the isotope:Iron-51; Fe-51Symbol:⁵¹Fe or 5126FeMass number A:51 (= number of nucleons)Atomic number Z:26 (= number of protons)Neutrons N:25Isotopic mass:50.956841(10) u (atomic weight of Iron-51)Nuclide mass:50.9425783 u (calculated nuclear mass without electrons)Mass excess:-40.20235 MeVMass defect:0.463232732 u (per nucleus)Nuclear binding energy:431.49851046 MeV (per nucleus)
8.46075511 MeV (average binding energy per nucleon)Separation energy:S_N = 13.797(12) MeV (first neutron)
S_P = 4.864(9) MeV (first proton)Half-life:305(2) msDecay constant λ:2.2726137067539 s^-1Specific activity α:2.73719997245 × 10⁺²² Bq g^-1
739783776340.27 Ci g^-1Spin and parity:
(nuclear angular momentum)5/2-Mirror nucleus:Manganese-51Year of discovery:1972

Radioactive Decay

Half-life T_½ = 305(2) ms respectively 3.05 × 10^-1 seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
β⁺	⁵¹Mn	100 %	8.041(9) MeV

Parent Nuclides

Direct parent isotope is: ⁵¹Co.

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 25) and isobaric (same nucleon number A = 51) with Iron-51. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 25	Isobar A = 51
11	³⁶Na
12	³⁷Mg
13	³⁸Al
14	³⁹Si
15	⁴⁰P
16	⁴¹S
17	⁴²Cl	⁵¹Cl
18	⁴³Ar	⁵¹Ar
19	⁴⁴K	⁵¹K
20	⁴⁵Ca	⁵¹Ca
21	⁴⁶Sc	⁵¹Sc
22	⁴⁷Ti	⁵¹Ti
23	⁴⁸V	⁵¹V
24	⁴⁹Cr	⁵¹Cr
25	⁵⁰Mn	⁵¹Mn
26	⁵¹Fe	⁵¹Fe
27	⁵²Co	⁵¹Co
28	⁵³Ni	⁵¹Ni
29	⁵⁴Cu
30	⁵⁵Zn