Fluorine-20

Properties and data of the isotope ²⁰F.

Contents

General Data

Radioactive Decay

Parent Nuclides

Isotones und Isobares

Literature

Fluorine-20 is a radioisotope of the chemical element fluorine, which has 11 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 20. The very short-lived, only artificially produced, unstable and thus radioactive nuclide has no practical significance; the study of ²⁰F is exclusively for academic purposes and experimental research.

The isotope was first described in 1935 as a product of the irradiation of natural fluorine with deuterons (0.8 MeV; hydrogen-2) in a cloud chamber [1]:

¹⁹F(d,p)²⁰F.

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

General data

Name of the isotope:Fluorine-20; F-20Symbol:²⁰F or 209FMass number A:20 (= number of nucleons)Atomic number Z:9 (= number of protons)Neutrons N:11Isotopic mass:19.99998125(3) u (atomic weight of Fluorine-20)Nuclide mass:19.9950441 u (calculated nuclear mass without electrons)Mass excess:-0.01747 MeVMass defect:0.165758114 u (per nucleus)Nuclear binding energy:154.40268864 MeV (per nucleus)
7.72013443 MeV (average binding energy per nucleon)Separation energy:S_N = 6.60134(3) MeV (first neutron)
S_P = 10.6393(26) MeV (first proton)Half-life:11.0062(80) sDecay constant λ:0.062977883425701 s^-1Specific activity α:1.996114131843 × 10⁺²¹ Bq g^-1
53949030590.362 Ci g^-1Spin and parity:
(nuclear angular momentum)2+Isobaric spin: 1Magnetic dipole moment:μ(μ_N) = +2.09335(9)Quadrupole moment Q:- 0.042(3) barn (100 fm²)Nuclear g-factor:g_l = 1.046675Mirror nucleus:Sodium-20Year of discovery:1935

Radioactive Decay

Half-life T_½ = 11.0062(80) s respectively 1.10062 × 10¹ seconds s.

Decay mode	Daughter	Probability	Decay energy	Details	γ energy (intensity)
β^-	²⁰Ne	100 %	7.02447(3) MeV	β^-: 2.4815(10) MeV [99.9913(8) %]	1.633602(15) MeV [99.9995 %]

Parent Nuclides

Direct parent isotope is: ²⁰O.

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 11) and isobaric (same nucleon number A = 20) with Fluorine-20. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 11	Isobar A = 20
4	¹⁵Be
5	¹⁶B	²⁰B
6	¹⁷C	²⁰C
7	¹⁸N	²⁰N
8	¹⁹O	²⁰O
9	²⁰F	²⁰F
10	²¹Ne	²⁰Ne
11	²²Na	²⁰Na
12	²³Mg	²⁰Mg
13	²⁴Al	²⁰Al
14	²⁵Si
15	²⁶P
16	²⁷S
17	²⁸Cl

Data changes (history)

The half-life of fluorine-20 has been repeatedly measured and discussed in recent decades - sometimes with considerable discrepancies. For overviews, see [2, 3].

External data and identifiers

Adopted Levels, Gammas:NuDat 20F

Literature and References

[1] - H. R. Crane, L. A. Delsasso, W. A. Fowler, C. C. Lauritsen:
The Emission of Negative Electrons from Lithium and Fluorine Bombarded with Deuterons.
In: Physical Review, 47, 971, (1935), DOI 10.1103/PhysRev.47.971.

[2] - M. Hughes, E. A. George, O. Naviliat-Cuncic et al.:
Measurement of the ²⁰F half-life.
In: Physical Review C, 97, 054328, (2018), DOI 10.1103/PhysRevC.97.054328.

[3] - D. P. Burdette, M. Brodeur, T. Ahn et al.:
Resolving the discrepancy in the half-life of ²⁰F.
In: Physical Review C, 99, 015501, (2019), DOI 10.1103/PhysRevC.99.015501.