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Chromium-51

Properties and data of the isotope 51Cr.


Contents

Chromium-51 is the radioisotope of the chemical element chromium, which, in addition to the element-specific 24 protons, has 27 neutrons in the atomic nucleus, resulting in the mass number 51.

See also: list of Chromium isotopes.

 

General data

Name of the isotope:Chromium-51; Cr-51Symbol:51Cr or 5124CrMass number A:51 (= number of nucleons)Atomic number Z:24 (= number of protons)Neutrons N:27Isotopic mass:50.94476539(18) u (atomic weight of Chromium-51)Nuclide mass:50.9315998 u (calculated nuclear mass without electrons)Mass excess:-51.45071 MeVMass defect:0.47698811 u (per nucleus)Nuclear binding energy:444.31156254 MeV (per nucleus)
8.71199142 MeV (average binding energy per nucleon)
Separation energy:SN = 9.26067(15) MeV (first neutron)
SP = 9.51645(15) MeV (first proton)
Half-life:27.704(4) dDecay constant λ:2.895804509109 × 10-7 s-1Specific activity α:3.487788531339 × 10+15 Bq g-1
94264.554901059 Ci g-1
Spin and parity:
(nuclear angular momentum)
7/2-Magnetic dipole moment:μ(μN) = (-)0.934(5)Mirror nucleus:Cobalt-51Year of discovery:1940

 

Radioactive Decay

Chromium-51 decays radioactively by electron capture and emitting gamma rays (0.320 MeV).

Half-life T½ = 27.704(4) d respectively 2.3936256 × 106 seconds s.

Decay
mode
DaughterProbabilityDecay energyγ energy
(intensity)
EC51V100 %0.75239(19) MeV0.3200835(4) MeV
9.91(1) %

 

Parent Nuclides

Direct parent isotope is: 51Mn.

 

Chromium-51 as a Radionuclide in Medicine

The radionuclide chromium-51 has been used as a tracer in radiomedicine for decades. As a radiodiagnostic, it is used in nephrology to determine the glomerular filtration rate and in hematology to determine the volume or mass of red blood cells, to study the survival time of red blood cells and to assess blood loss. Corresponding 51Cr radiopharmaceuticals include:

- Chromium (51Cr) edetate (renal system, ATC-Code V09CX04),
- Chromium (51Cr) chromate labelled cells (cardiovascular system, ATC V09GX03). This includes e.g. B. sodium (51Cr) chromate.

More recently, reports have appeared indicating a decline in the use of Cr-51 preparations and the search for alternative radioisotopes for the stated uses [1].

 

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 27) and isobaric (same nucleon number A = 51) with Chromium-51. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

 

ZIsotone N = 27Isobar A = 51
1138Na
1239Mg
1340Al
1441Si
1542P
1643S
1744Cl51Cl
1845Ar51Ar
1946K51K
2047Ca51Ca
2148Sc51Sc
2249Ti51Ti
2350V51V
2451Cr51Cr
2552Mn51Mn
2653Fe51Fe
2754Co51Co
2855Ni51Ni
2956Cu
3057Zn
3158Ga
3259Ge

 

External data and identifiers

CAS:14392-02-0InChI Key:VYZAMTAEIAYCRO-BJUDXGSMSA-NSMILES:[51Cr]PubChem:ID 104786Adopted Levels, Gammas:NuDat 51Cr

 

Literature and References

[0] - Research articles in scientific journals via PubMed: Chromium-51.

[1] - J. Dinet et al.:
Discontinuation of Chromium-51 for clinical use: What are the possible alternatives for radiopharmacies and nuclear medicine departments?.
In: Annales Pharmaceutiques Françaises, (2020), DOI 10.1016/j.pharma.2020.01.006.

 


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Last update: 2023-10-04


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