Fluorine-15

Properties and data of the isotope ¹⁵F.

Contents

Fluorine-15 is a radioisotope of the chemical element fluorine, which has 6 neutrons in its atomic nucleus in addition to the element-specific 9 protons; the sum of the number of these atomic nucleus building blocks results in a mass number of 15. The very short-lived, only artificially produced, unstable and thus radioactive nuclide has no practical significance; the study of ¹⁵F is exclusively for academic purposes.

The first observation of the proton-rich nuclide was made by irradiating neon with helium-3 particles (87.8 MeV) [1, (1978)]:

²⁰Ne(³He,⁸Li)¹⁵F.

See also: List of individual Fluorine isotopes (and general data sources).

General data

Name of the isotope:Fluorine-15; F-15Symbol:¹⁵F or 159FMass number A:15 (= number of nucleons)Atomic number Z:9 (= number of protons)Neutrons N:6Nucleon pairing (Z - N):odd - evenNuclear ratio (N/Z ratio):0.66666666666667 (= neutron-proton ratio)Neutron excess (N-Z):-3Isotopic mass:15.017785(15) u (atomic weight of Fluorine-15)Nuclide mass:15.0128478 u (calculated nuclear mass without electrons)Mass excess:16.56662 MeVMass defect:0.104629784 u (per nucleus)Nuclear binding energy:97.46201602 MeV (per nucleus)
6.49746773 MeV (average binding energy per nucleon)Separation energy:S_N = 23.469(43) MeV (first neutron)Half-life:1.1(3) zsDecay constant λ:6.301338005090 × 10⁺²⁰ s^-1Specific activity α:2.529836338181 × 10⁺⁴³ Bq g^-1
6.837395508599 × 10⁺³² Ci g^-1Spin and parity:
(nuclear angular momentum)1/2+Mirror nucleus:Carbon-15Year of discovery:1978

Radioactive Decay

Half-life T_½ = 1.1(3) zs respectively 1.1 × 10^-21 seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
p	¹⁴O	100 %	13.7 MeV

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 6) and isobaric (same nucleon number A = 15) with Fluorine-15. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 6	Isobar A = 15
1	⁷H
2	⁸He
3	⁹Li
4	¹⁰Be	¹⁵Be
5	¹¹B	¹⁵B
6	¹²C	¹⁵C
7	¹³N	¹⁵N
8	¹⁴O	¹⁵O
9	¹⁵F	¹⁵F
10	¹⁶Ne	¹⁵Ne
11	¹⁷Na
12	¹⁸Mg

External data and identifiers

Adopted Levels, Gammas:NuDat 15F

Literature and References

[1] - G. J. KeKelis, M. S. Zisman, D. K. Scott et al.:
Masses of the unbound nuclei ¹⁶Ne, ¹⁵F, and ¹²O.
In: Physical Review C, 17, 1929, (1978), DOI 10.1103/PhysRevC.17.1929.