Physics:Isotopes of fluorine

Template:Infobox fluorine isotopes Fluorine (₉F) has 19 known isotopes ranging from to and two isomers ( and ). Only fluorine-19 is stable and naturally occurring in more than trace quantities; therefore, fluorine is a monoisotopic and a mononuclidic element.

The longest-lived radioisotope is [[fluorine-18|]] with a half-life of 109.734 minutes, followed by [[fluorine-17|]] with 64.37 seconds. These unstable isotopes participate in the CNO cycle within stars. All other fluorine isotopes have half-lives of less than 12 seconds, and most of those less than 1/2 second.

List of isotopes

Nuclide	Z	N	Isotopic mass (u)	Half-life	Decay mode	Daughter isotope	Spin and parity	Physics:Natural abundance (mole fraction)
	Excitation energy							Normal proportion	Range of variation
	9	4	13.045120(540)#		p ?		1/2+#
	9	5	14.034320(40)	500(60) ys [910(100) keV]	p ?		2−
	9	6	15.017785(15)	1.1(3) zs [376 keV]	p		1/2+
	9	7	16.011460(6)	21(5) zs [21.3(5.1) keV]	p		0−
	9	8	17.00209524(27)	64.370(27) s	β+		5/2+
[[Fluorine-18|]]	9	9	18.0009373(5)	109.734(8) min	β+		1+	Trace
	1121.36(15) keV			162(7) ns	IT		5+
	9	10	18.998403162067(883)	Stable			1/2+	1
	9	11	19.99998125(3)	11.0062(80) s	β−		2+
	9	12	20.9999489(19)	4.158(20) s	β−		5/2+
	9	13	22.002999(13)	4.23(4) s	β− (> 89%)		(4+)
					β−n (< 11%)
	9	14	23.003530(40)	2.23(14) s	β− (> 86%)		5/2+
					β−n (< 14%)
	9	15	24.008100(100)	384(16) ms	β− (> 94.1%)		3+
					β−n (< 5.9%)
	9	16	25.012170(100)	80(9) ms	β− (76.9(4.5)%)		(5/2+)
					β−n (23.1(4.5)%)
					β−2n ?	?
	9	17	26.020050(110)	8.2(9) ms	β− (86.5(4.0)%)		1+
					β−n (13.5(4.0)%)
					β−2n ?	?
	643.4(1) keV			2.2(1) ms	IT (82(11)%)		(4+)
					β−n (12(8)%)
					β− ?	?
	9	18	27.026980(130)	5.0(2) ms	β−n (77(21)%)		5/2+#
					β− (23(21)%)
					β−2n ?	?
	9	19	28.035860(130)	46 zs	n		(4−)
	9	20	29.043100(560)	2.5(3) ms	β−n (60(40)%)		(5/2+)
					β− (40(40)%)
					β−2n ?	?
	9	21	30.05256(54)#	0.96+0.56 −0.41 zs	n
	9	22	31.06020(570)#	2 ms# [> 260 ns]	β− ?	?	5/2+#
					β−n ?	?
					β−2n ?	?

Fluorine-18

Main article: Physics:Fluorine-18

Of the unstable nuclides of fluorine, has the longest half-life, 109.734(8) min. It decays to via β⁺ decay. For this reason is a commercially important source of positrons. Its major value is in the production of the radiopharmaceutical fludeoxyglucose, used in positron emission tomography in medicine.

Fluorine-18 is the second lightest unstable nuclide (after beryllium-8, with 4 protons and 4 neutrons) with equal numbers of protons and neutrons and lightest such with an odd atomic number, having 9 of each. (See also the parity discussion of nuclide stability.)

Fluorine-19

Fluorine-19 is the only stable isotope of fluorine. Its abundance is 100%; no other isotopes of fluorine exist in significant quantities. Its binding energy is 147801.3648(38) keV. Fluorine-19 is NMR-active with a spin of 1/2+, so it is used in fluorine-19 NMR spectroscopy.

Isomers

Only two nuclear isomers (long-lived excited nuclear states), fluorine-18m and fluorine-26m, have been characterized. The half-life of before it undergoes isomeric transition is 162(7) nanoseconds. This is less than the decay half-life of any of the particle-bound fluorine radioisotope nuclear ground states. The half-life of is 2.2(1) milliseconds; it decays mainly to its ground state of or (rarely, via beta-minus decay) to one of high excited states of with delayed neutron emission.

See also

Daughter products other than fluorine

• Isotopes of neon
• Isotopes of oxygen

Sources

• Chisté, V.; Bé, M. M. (2011). Bé, M. M.. ed. Table de radionucléides (Report). CEA (Commissariat à l'énergie atomique et aux énergies alternatives), LIST, LNE-LNHB (Laboratoire National Henri Becquerel/Commissariat à l'Energie Atomique).