Fluorine-26

Properties and data of the isotope ²⁶F.

Contents

Fluorine-26 is a radioisotope of the chemical element fluorine, which has 17 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 26. The very short-lived, only artificially produced, unstable and thus radioactive nuclide has no practical significance; the study of ²⁶F is exclusively for academic purposes.

According to a report from 1979, the neutron-rich instable isotope was discovered during the fragmentation of calcium-48 ions - accelerated to 212 MeV per nucleon - on a Be target [1].

General data

Name of the isotope:Fluorine-26; F-26Symbol:²⁶F or 269FMass number A:26 (= number of nucleons)Atomic number Z:9 (= number of protons)Neutrons N:17Isotopic mass:26.020050(110) u (atomic weight of Fluorine-26)Nuclide mass:26.0151128 u (calculated nuclear mass without electrons)Mass excess:18.67645 MeVMass defect:0.19767886 u (per nucleus)Nuclear binding energy:184.13667202 MeV (per nucleus)
7.08217969 MeV (average binding energy per nucleon)Separation energy:S_N = 0.731(144) MeV (first neutron)
S_P = 15.943(197) MeV (first proton)Half-life:8.2(9) msDecay constant λ:84.530143970725 s^-1Specific activity α:1.957893976547 × 10⁺²⁴ Bq g^-1
52916053420211 Ci g^-1Spin and parity:
(nuclear angular momentum)1+Year of discovery:1979

Radioactive Decay

Half-life T_½ = 8.2(9) ms respectively 8.2 × 10^-3 seconds s.

Decay mode	Daughter	Probability	Decay energy
β^-	²⁶Ne	86.5(40) %	18.190(110) MeV
β^-, n	²⁵Ne	13.5(40) %	12.639(111) MeV
β^-, 2n	²⁴Ne	?

Nuclear Isomers

Nuclear isomers or excited states with the activation energy in keV related to the ground state.

Nuclear Isomer	Excitation Energy	Half-life	Spin
^26mF	643.4(1) keV	2.2(1) ms	(4+)

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 17) and isobaric (same nucleon number A = 26) with Fluorine-26. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 17	Isobar A = 26
7	²⁴N
8	²⁵O	²⁶O
9	²⁶F	²⁶F
10	²⁷Ne	²⁶Ne
11	²⁸Na	²⁶Na
12	²⁹Mg	²⁶Mg
13	³⁰Al	²⁶Al
14	³¹Si	²⁶Si
15	³²P	²⁶P
16	³³S	²⁶S
17	³⁴Cl
18	³⁵Ar
19	³⁶K
20	³⁷Ca
21	³⁸Sc
22	³⁹Ti
23	⁴⁰V
24	⁴¹Cr
25	⁴²Mn

External data and identifiers

Adopted Levels, Gammas:NuDat 26F

Literature and References

[1] - G. D. Westfall, T. J. M. Symons, D. E. Greiner et al.:
Production of Neutron-Rich Nuclides by Fragmentation of 212-MeV/amu ⁴⁸Ca.
In: Physical Review Letters,43, 1859, (1979), DOI 10.1103/PhysRevLett.43.1859.