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Phosphorus-32

Properties and data of the isotope 32P.


Contents

 

Phosphorus-32 isotope

Phosphorus-32 is a radioisotope of the chemical element phosphorus, which has 17 neutrons in the atomic nucleus in addition to the element-specific 15 protons, resulting in a mass number of 32.

See also: list of Phosphorus isotopes.

 

General data

Name of the isotope:Phosphorus-32; P-32Symbol:32P or 3215PMass number A:32 (= number of nucleons)Atomic number Z:15 (= number of protons)Neutrons N:17Isotopic mass:31.97390764(4) u (atomic weight of Phosphorus-32)Nuclide mass:31.965679 u (calculated nuclear mass without electrons)Mass excess:-24.30488 MeVMass defect:0.29077141200001 u (per nucleus)Nuclear binding energy:270.85182565 MeV (per nucleus)
8.46411955 MeV (average binding energy per nucleon)
Separation energy:SN = 7.93565(4) MeV (first neutron)
SP = 8.64481(6) MeV (first proton)
Half-life:14.268(5) dDecay constant λ:5.622747975915 × 10-7 s-1Specific activity α:1.092289688093 × 10+16 Bq g-1
295213.42921438 Ci g-1
Spin and parity:
(nuclear angular momentum)
1+Magnetic dipole moment:μ(μN) = - 0.2528(2)Nuclear g-factor:gl = -0.2528Mirror nucleus:Chlorine-32Year of discovery:1934

 

Radioactive Decay

Phosphorus-32 is a pure beta emitter: the radioactive β-decay into the ground state of the stable isotope Sulfur-32 leads to the 100% emission of electrons e- with an energy of 0.69503(10) MeV; the remaining part of the total energy is carried by electron antineutrinos ve (1.016986(20) MeV).

Half-life T½ = 14.268(5) d respectively 1.2327552 × 106 seconds s.

Decay
mode
DaughterProbabilityDecay energyγ energy
(intensity)
β-32S100 %1.71066(4) MeV

 

Origin and radioactive decay of phosphoris-32

 

Parent Nuclides

Direct parent isotope is: 32Si.

 

Formation

Phosphorus-32 is produced synthetically by irradiating sulfur-32 with moderately fast neutrons; overall, the following nuclear reactions are common for 32 production:

The synthesis takes place in nuclear reactors.

 

Occurrence

Phosphorus-32 occurs naturally on Earth in small but detectable trace amounts. The radioisotope is formed - alongside Phosphorus-33; both are occasionally referred to individually, but also in combination as radiophosphorus - by the effect of cosmic radiation (spallation) on argon atoms - mainly in the upper troposphere and to a lesser extent in the lower stratosphere. 32P rapidly oxidizes to the phosphate 32PO43-, which binds to aerosols and reaches the ocean and Earth´s surface with precipitation [2].

 

Phosphorus-32 as a Radionuclide in Medicine

The radioactive isotope phosphorus-32 plays a role in medicine and biochemical research. As a medical radionuclide, it can be used to detect malignant tumors, since suitable preparations labeled with 32P accumulate more strongly in cancer cells than in healthy cells. Medicines listed by the WHO are:

- Phosphorous (32P) chromicphosphate colloid (anti-inflammatory) and

- Sodium Phosphate P-32.

 

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 17) and isobaric (same nucleon number A = 32) with Phosphorus-32. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

 

ZIsotone N = 17Isobar A = 32
724N
825O
926F
1027Ne32Ne
1128Na32Na
1229Mg32Mg
1330Al32Al
1431Si32Si
1532P32P
1633S32S
1734Cl32Cl
1835Ar32Ar
1936K32K
2037Ca
2138Sc
2239Ti
2340V
2441Cr
2542Mn

 

External data and identifiers

Adopted Levels, Gammas:NuDat 32P

 

Literature and References

[1] - K. V. Vimalnath, Priyalata Shetty, A. Rajeswari et al.:
Reactor production of 32P for medical applications: an assessment of 32S(n,p)32P and 31P(n,γ)32P methods.
In: Journal of Radioanalytical and Nuclear Chemistry, 301, (2014), DOI 10.1007/s10967-014-3115-0.

[2] - Michael Schubert, Mang Lin, Jordan F. Clark et al.:
Short-lived natural radionuclides as tracers in hydrogeological studies - A review.
In: Science of The Total Environment, 920, 170800, (2024), DOI 10.1016/j.scitotenv.2024.170800.

 


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Last update: 2024-08-23


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