Isotopes of francium

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Isotopes of francium  (87Fr)
Main isotopes [1] Decay
abun­dance half-life (t1/2) mode pro­duct
212Fr synth 20.0 min β+ 212Rn
α 208At
221Fr trace 4.8 min α 217At
222Frsynth14.2 min β− 222Ra
223Frtrace22.00 minβ− 223Ra
α 219At

Francium (87Fr) has no stable isotopes. A standard atomic weight cannot be given. Its most stable isotope is 223Fr with a half-life of 22 minutes, occurring in trace quantities in nature as an intermediate decay product of 235U.

Of elements whose most stable isotopes have been identified with certainty, francium is the most unstable. All elements with atomic number of 106 (seaborgium) or greater have most-stable-known isotopes shorter than that of francium, but as those elements have only a relatively small number of isotopes discovered, the possibility remains that undiscovered isotopes of these elements may have longer half-lives.

List of isotopes

Nuclide
[n 1] 		Historic
name		 Z N Isotopic mass (Da)
[n 2] [n 3] 		Half-life
[n 4] 		Decay
mode
[n 5] 		Daughter
isotope
Spin and
parity
[n 6] [n 4] 		Isotopic
abundance
Excitation energy [n 4]
197Fr87110197.01101(6)2.3(19) ms α 193At(7/2−)
198Fr87111198.01028(3)15(3) msα194At3+#
199Fr87112199.00726(4)16(7) msα195At1/2+#
200Fr87113200.00657(8)24(10) msα196At3+#
200mFr60(110) keV190(120) msα196At10−#
201Fr87114201.00386(8)67(3) msα (99%)197At(9/2−)
β+ (1%)201Rn
202Fr87115202.00337(5)290(30) msα (97%)198At(3+)
β+ (3%)202Rn
202mFr330(90)# keV340(40) msα (97%)198At(10−)
β+ (3%)202Rn
203Fr87116203.000925(17)0.55(2) sα (95%)199At(9/2−)#
β+ (5%)203Rn
204Fr87117204.000653(26)1.7(3) sα (96%)200At(3+)
β+ (4%)204Rn
204m1Fr50(4) keV2.6(3) sα (90%)200At(7+)
β+ (10%)204Rn
204m2Fr326(4) keV1.7(6) s(10−)
205Fr87118204.998594(8)3.80(3) sα (99%)201At(9/2−)
β+ (1%)205Rn
206Fr87119205.99867(3)~16 sβ+ (58%)206Rn(2+, 3+)
α (42%)202At
206m1Fr190(40) keV15.9(1) s(7+)
206m2Fr730(40) keV700(100) ms(10−)
207Fr87120206.99695(5)14.8(1) sα (95%)203At9/2−
β+ (5%)207Rn
208Fr87121207.99714(5)59.1(3) sα (90%)204At7+
β+ (10%)208Rn
209Fr87122208.995954(16)50.0(3) sα (89%)205At9/2−
β+ (11%)209Rn
210Fr87123209.996408(24)3.18(6) minα (60%)206At6+
β+ (40%)210Rn
211Fr87124210.995537(23)3.10(2) minα (80%)207At9/2−
β+ (20%)211Rn
212Fr87125211.996202(28)20.0(6) minβ+ (57%)212Rn5+
α (43%)208At
213Fr87126212.996189(8)34.14(6) s [2] α (99.45%)209At9/2−
β+ (.55%)213Rn
214Fr87127213.998971(9)5.0(2) msα210At(1−)
214m1Fr123(6) keV3.35(5) msα210At(8−)
214m2Fr638(6) keV103(4) ns(11+)
214m3Fr6477+Y keV108(7) ns(33+)
215Fr87128215.000341(8)86(5) nsα211At9/2−
216Fr87129216.003198(15)0.70(2) μsα212At(1−)
216mFr219(6) keV850(30) nsα [n 7] 212At(9−)
217Fr87130217.004632(7)16.8(19) μsα213At9/2−
218Fr87131218.007578(5)1.0(6) msα214At1−
218m1Fr86(4) keV22.0(5) msα214At(8−)
218m2Fr200(150)# keVhigh
219Fr87132219.009252(8)20(2) msα215At9/2−
220Fr87133220.012327(4)27.4(3) sα (99.65%)216At1+
β− (.35%)220Ra
221Fr87134221.014255(5)4.9(2) minα (99.9%)217At5/2−Trace [n 8]
β− (.1%)221Ra
CD (8.79×10−11%) [n 9] 207Tl
14C
222Fr87135222.017552(23)14.2(3) minβ−222Ra2−
223FrActinium K87136223.0197359(26)22.00(7) minβ− (99.99%)223Ra3/2(−)Trace [n 10]
α (.006%)219At
224Fr87137224.02325(5)3.33(10) minβ−224Ra1−
225Fr87138225.02557(3)4.0(2) minβ−225Ra3/2−
226Fr87139226.02939(11)49(1) sβ−226Ra1−
227Fr87140227.03184(11)2.47(3) minβ−227Ra1/2+
228Fr87141228.03573(22)#38(1) sβ−228Ra2−
229Fr87142229.03845(4)50.2(4) sβ−229Ra(1/2+)#
230Fr87143230.04251(48)#19.1(5) sβ−230Ra
231Fr87144231.04544(50)#17.6(6) sβ−231Ra(1/2+)#
232Fr87145232.04977(69)#5(1) sβ−232Ra
233Fr87146233.052518(21)900(100) msβ−233Ra1/2+ #
This table header & footer:
  1. ↑ mFr – Excited nuclear isomer.
  2. ↑ ( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.
  3. ↑ # – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).
  4. 1 2 3 # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
  5. ↑ Modes of decay:
    CD: Cluster decay
    IT: Isomeric transition
  6. ↑ ( ) spin value – Indicates spin with weak assignment arguments.
  7. ↑ Theoretically capable of β+ decay to 216Rn [1]
  8. ↑ Intermediate decay product of 237Np
  9. ↑ The nuclide with the lowest atomic number known to undergo cluster decay
  10. ↑ Intermediate decay product of 235U

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Radium (88Ra) has no stable or nearly stable isotopes, and thus a standard atomic weight cannot be given. The longest lived, and most common, isotope of radium is 226Ra with a half-life of 1600 years. 226Ra occurs in the decay chain of 238U. Radium has 34 known isotopes from 201Ra to 234Ra.

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There are 42 isotopes of polonium (84Po). They range in size from 186 to 227 nucleons. They are all radioactive. 210Po with a half-life of 138.376 days has the longest half-life of any naturally-occurring isotope of polonium and is the most common isotope of polonium. It is also the most easily synthesized polonium isotope. 209Po, which does not occur naturally, has the longest half-life of all isotopes of polonium at 124 years. 209Po can be made by using a cyclotron to bombard bismuth with protons, as can 208Po.

<span class="mw-page-title-main">Isotopes of thallium</span> Nuclides with atomic number of 81 but with different mass numbers

Thallium (81Tl) has 41 isotopes with atomic masses that range from 176 to 216. 203Tl and 205Tl are the only stable isotopes and 204Tl is the most stable radioisotope with a half-life of 3.78 years. 207Tl, with a half-life of 4.77 minutes, has the longest half-life of naturally occurring Tl radioisotopes. All isotopes of thallium are either radioactive or observationally stable, meaning that they are predicted to be radioactive but no actual decay has been observed.

There are seven stable isotopes of mercury (80Hg) with 202Hg being the most abundant (29.86%). The longest-lived radioisotopes are 194Hg with a half-life of 444 years, and 203Hg with a half-life of 46.612 days. Most of the remaining 40 radioisotopes have half-lives that are less than a day. 199Hg and 201Hg are the most often studied NMR-active nuclei, having spin quantum numbers of 1/2 and 3/2 respectively. All isotopes of mercury are either radioactive or observationally stable, meaning that they are predicted to be radioactive but no actual decay has been observed. These isotopes are predicted to undergo either alpha decay or double beta decay.

Naturally occurring platinum (78Pt) consists of five stable isotopes (192Pt, 194Pt, 195Pt, 196Pt, 198Pt) and one very long-lived (half-life 4.83×1011 years) radioisotope (190Pt). There are also 34 known synthetic radioisotopes, the longest-lived of which is 193Pt with a half-life of 50 years. All other isotopes have half-lives under a year, most under a day. All isotopes of platinum are either radioactive or observationally stable, meaning that they are predicted to be radioactive but no actual decay has been observed. Platinum-195 is the most abundant isotope.

Natural hafnium (72Hf) consists of five observationally stable isotopes (176Hf, 177Hf, 178Hf, 179Hf, and 180Hf) and one very long-lived radioisotope, 174Hf, with a half-life of 7.0×1016 years. In addition, there are 34 known synthetic radioisotopes, the most stable of which is 182Hf with a half-life of 8.9×106 years. This extinct radionuclide is used in hafnium–tungsten dating to study the chronology of planetary differentiation.

Natural holmium (67Ho) contains one observationally stable isotope, 165Ho. The below table lists 36 isotopes spanning 140Ho through 175Ho as well as 33 nuclear isomers. Among the known synthetic radioactive isotopes; the most stable one is 163Ho, with a half-life of 4,570 years. All other radioisotopes have half-lives not greater than 1.117 days in their ground states, and most have half-lives under 3 hours.

Promethium (61Pm) is an artificial element, except in trace quantities as a product of spontaneous fission of 238U and 235U and alpha decay of 151Eu, and thus a standard atomic weight cannot be given. Like all artificial elements, it has no stable isotopes. It was first synthesized in 1945.

Naturally occurring praseodymium (59Pr) is composed of one stable isotope, 141Pr. Thirty-eight radioisotopes have been characterized with the most stable being 143Pr, with a half-life of 13.57 days and 142Pr, with a half-life of 19.12 hours. All of the remaining radioactive isotopes have half-lives that are less than 5.985 hours and the majority of these have half-lives that are less than 33 seconds. This element also has 15 meta states with the most stable being 138mPr, 142mPr and 134mPr.

<span class="mw-page-title-main">Isotopes of lanthanum</span> Nuclides with atomic number of 57 but with different mass numbers

Naturally occurring lanthanum (57La) is composed of one stable (139La) and one radioactive (138La) isotope, with the stable isotope, 139La, being the most abundant (99.91% natural abundance). There are 39 radioisotopes that have been characterized, with the most stable being 138La, with a half-life of 1.02×1011 years; 137La, with a half-life of 60,000 years and 140La, with a half-life of 1.6781 days. The remaining radioactive isotopes have half-lives that are less than a day and the majority of these have half-lives that are less than 1 minute. This element also has 12 nuclear isomers, the longest-lived of which is 132mLa, with a half-life of 24.3 minutes. Lighter isotopes mostly decay to isotopes of barium and heavy ones mostly decay to isotopes of cerium. 138La can decay to both.

Naturally occurring barium (56Ba) is a mix of six stable isotopes and one very long-lived radioactive primordial isotope, barium-130, identified as being unstable by geochemical means (from analysis of the presence of its daughter xenon-130 in rocks) in 2001. This nuclide decays by double electron capture (absorbing two electrons and emitting two neutrinos), with a half-life of (0.5–2.7)×1021 years (about 1011 times the age of the universe).

Antimony (51Sb) occurs in two stable isotopes, 121Sb and 123Sb. There are 35 artificial radioactive isotopes, the longest-lived of which are 125Sb, with a half-life of 2.75856 years; 124Sb, with a half-life of 60.2 days; and 126Sb, with a half-life of 12.35 days. All other isotopes have half-lives less than 4 days, most less than an hour.

Indium (49In) consists of two primordial nuclides, with the most common (~ 95.7%) nuclide (115In) being measurably though weakly radioactive. Its spin-forbidden decay has a half-life of 4.41×1014 years, much longer than the currently accepted age of the Universe.

Arsenic (33As) has 33 known isotopes and at least 10 isomers. Only one of these isotopes, 75As, is stable; as such, it is considered a monoisotopic element. The longest-lived radioisotope is 73As with a half-life of 80 days. Arsenic has been proposed as a "salting" material for nuclear weapons. A jacket of 75As, irradiated by the intense high-energy neutron flux from an exploding thermonuclear weapon, would transmute into the radioactive isotope 76As with a half-life of 1.0778 days and produce approximately 1.13 MeV gamma radiation, significantly increasing the radioactivity of the weapon's fallout for several hours. Such a weapon is not known to have ever been built, tested, or used.

Germanium (32Ge) has five naturally occurring isotopes, 70Ge, 72Ge, 73Ge, 74Ge, and 76Ge. Of these, 76Ge is very slightly radioactive, decaying by double beta decay with a half-life of 1.78 × 1021 years (130 billion times the age of the universe).

Naturally occurring zinc (30Zn) is composed of the 5 stable isotopes 64Zn, 66Zn, 67Zn, 68Zn, and 70Zn with 64Zn being the most abundant. Twenty-five radioisotopes have been characterised with the most abundant and stable being 65Zn with a half-life of 244.26 days, and 72Zn with a half-life of 46.5 hours. All of the remaining radioactive isotopes have half-lives that are less than 14 hours and the majority of these have half-lives that are less than 1 second. This element also has 10 meta states.

Copper (29Cu) has two stable isotopes, 63Cu and 65Cu, along with 27 radioisotopes. The most stable radioisotope is 67Cu with a half-life of 61.83 hours, while the least stable is 54Cu with a half-life of approximately 75 ns. Most have half-lives under a minute. Unstable copper isotopes with atomic masses below 63 tend to undergo β+ decay, while isotopes with atomic masses above 65 tend to undergo β− decay. 64Cu decays by both β+ and β−.

Naturally occurring scandium (21Sc) is composed of one stable isotope, 45Sc. Twenty-five radioisotopes have been characterized, with the most stable being 46Sc with a half-life of 83.8 days, 47Sc with a half-life of 3.35 days, and 48Sc with a half-life of 43.7 hours and 44Sc with a half-life of 3.97 hours. All the remaining isotopes have half-lives that are less than four hours, and the majority of these have half-lives that are less than two minutes, the least stable being proton unbound 39Sc with a half-life shorter than 300 nanoseconds. This element also has 13 meta states with the most stable being 44m2Sc.

References

  1. 1 2 Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae.
  2. ↑ Fisichella, M.; Musumarra, A.; Farinon, F.; Nociforo, C.; Del Zoppo, A.; Figuera, P.; La Cognata, M.; Pellegriti, M. G.; Scuderi, V.; Torresi, D.; Strano, E. (2013-07-24). "Determination of the half-life of 213Fr with high precision". Physical Review C. 88 (1). American Physical Society (APS): 011303. Bibcode:2013PhRvC..88a1303F. doi:10.1103/physrevc.88.011303. ISSN   0556-2813.
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