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Properties and data of the isotope 19F.


Fluorine-19 is the only stable isotope of the chemical element fluorine. The atomic nucleus of the nuclide consists of the specific elements 9 protons and 10 neutrons; the sum of the nucleons gives the mass number 19.

19F is a NMR active nucleus and can therefore be measured using NMR spectroscopy for the detection and identification of fluorine-containing compounds. The corresponding analysis technique is fluorine-19 nuclear magnetic resonance spectroscopy (also fluorine NMR or 19F-NMR; see also below).

See also: list of Fluorine isotopes.


General data

Name of the isotope:Fluorine-19; F-19Symbol:19F or 199FMass number A:19 (= number of nucleons)Atomic number Z:9 (= number of protons)Neutrons N:10Isotopic mass:18.998403163(6) u (atomic weight of Fluorine-19)Nuclide mass:18.993466 u (calculated nuclear mass without electrons)Mass excess:-1.48744 MeVMass defect:0.158671285 u (per nucleus)Nuclear binding energy:147.80134995 MeV (per nucleus)
7.77901842 MeV (average binding energy per nucleon)
Separation energy:SN = 10.4319(5) MeV (first neutron)
SP = 7.9935998(10) MeV (first proton)
Half-life:stableSpin and parity:
(nuclear angular momentum)
1/2+Isobaric spin: 1/2Magnetic dipole moment:μ(μN) = +2.628321(4)Charge radius:2.8976(25) femtometer fmMirror nucleus:Neon-19Year of discovery:1920


Parent Nuclides

Direct parent isotopes are: 19Ne, 19O.



Comparison of the natural Fluorine isotopes including isotopic abundance (mole fraction of the isotope mixture in percent):


Atomic Mass maQuantityHalf-lifeSpin
Isotopic mixture
18.998403163 u100 %
Isotope 19F18.998403163(6) u100 %stable1/2+