Manganese-55
Properties and data of the isotope 55Mn.
Manganese-55 is a stable, naturally occuring of the chemical element manganese, which has 30 neutrons in its atomic nucleus in addition to the element-specific 25 protons; the sum of the number of these atomic nucleus building blocks results in a mass number of 55.
The discovery of the Mn isotope by mass spectroscopic detection was reported in 1923 [1].
See also: List of individual Manganese isotopes (and general data sources).
General data
Name of the isotope:Manganese-55; Mn-55Symbol:55Mn or 5525MnMass number A:55 (= number of nucleons)Atomic number Z:25 (= number of protons)Neutrons N:30Nucleon pairing (Z - N):odd - evenNuclear ratio (N/Z ratio):1.2 (= neutron-proton ratio)Neutron excess (N-Z):5Isotopic mass:54.93804304(28) u (atomic weight of Manganese-55)Nuclide mass:54.9243289 u (calculated nuclear mass without electrons)Mass excess:-57.71254 MeVMass defect:0.51753024 u (per nucleus)Nuclear binding energy:482.07631338 MeV (per nucleus)
8.76502388 MeV (average binding energy per nucleon)Separation energy:SN = 10.2256(10) MeV (first neutron)
SP = 8.06613(26) MeV (first proton)Half-life:stableSpin and parity:
(nuclear angular momentum)5/2-Magnetic dipole moment:μ(μN) = +3.4669(6)Charge radius:3.7057(22) femtometer fmMirror nucleus:Zinc-55Year of discovery:1923
Parent Nuclides
Direct parent isotopes are: 55Fe, 55Cr.
Occurrence
Comparison of the natural Manganese isotopes including isotopic abundance (mole fraction of the isotope mixture in percent):
| | Atomic Mass ma | Quantity | Half-life | Spin |
|---|
Manganese
Isotopic mixture | 54.938043 u | 100 % | | |
| Isotope 55Mn | 54.93804304(28) u | 100 % | stable | 5/2- |
NMR data
Nuclear magnetic properties and parameters of the NMR active Nuclide 55Mn
Isotope:55Mn-NMRQuantity:100 %Spin:5/2-Nuclearmagnetic moment
μ/μN:+3.4669(6)Gyromagnetic ratio γ:6.6452546 · 107 rad T-1 s-1
10.57625 MHz T-1Nuclear g-factor:gl = 1.38676Quadrupole moment Q:+0.33(1) barn (100 fm2)Line width parameter (factor):l = 348.48 fm4Resonance frequency:v0 = 10.5763 MHz at 1 TRelative Sensitivity:[related to 1H = 1.000]:
0.17881 (H0 = const.)
2.8981 (v0 = const.)
0.179 (at natural abundance)
relative receptivity as compared to 13C:
1050 (at natural abundance)Reference compound:
(conditions)0.82 molar solution of potassium permanganate KMnO4 in deuterium oxide D2O.Frequency ratio:Ξ(55Mn) = 24.789218 % [based on the reference substance]Chemical shift range:ca. 3000 ppm [-3000 to 0]
Isotones and Isobars
The following table shows the atomic nuclei that are isotonic (same neutron number N = 30) and isobaric (same nucleon number A = 55) with Manganese-55. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.
| Z | Isotone N = 30 | Isobar A = 55 |
|---|
| 13 | 43Al | |
| 14 | 44Si | |
| 15 | 45P | |
| 16 | 46S | |
| 17 | 47Cl | |
| 18 | 48Ar | |
| 19 | 49K | 55K |
| 20 | 50Ca | 55Ca |
| 21 | 51Sc | 55Sc |
| 22 | 52Ti | 55Ti |
| 23 | 53V | 55V |
| 24 | 54Cr | 55Cr |
| 25 | 55Mn | 55Mn |
| 26 | 56Fe | 55Fe |
| 27 | 57Co | 55Co |
| 28 | 58Ni | 55Ni |
| 29 | 59Cu | 55Cu |
| 30 | 60Zn | 55Zn |
| 31 | 61Ga | |
| 32 | 62Ge | |
| 33 | 63As | |
| 34 | 64Se | |
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: 2026-01-13
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