Isotopes of francium

Last updated

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 4.801 min α 217At
222Frsynth14.2 min β− 222Ra
223Frtrace22.00 minβ− 223Ra
α 219At

Francium (87Fr) has no stable isotopes, thus 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) [2]
[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+#
199Fr87112199.007269(15)16(7) msα195At1/2+#
200Fr87113200.00658(3)24(10) msα196At3+#
200mFr60(110) keV190(120) msα196At10−#
201Fr87114201.003852(10)67(3) msα (99%)197At(9/2−)
β+ (1%)201Rn
202Fr87115202.003330(6)290(30) msα (97%)198At(3+)
β+ (3%)202Rn
202mFr330(90)# keV340(40) msα (97%)198At(10−)
β+ (3%)202Rn
203Fr87116203.000941(7)0.55(2) sα (95%)199At(9/2−)#
β+ (5%)203Rn
204Fr87117204.000652(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
206Fr87119205.998661(30)~16 sβ+ (58%)206Rn(2+, 3+)
α (42%)202At
206m1Fr190(40) keV15.9(1) s(7+)
206m2Fr730(40) keV700(100) ms(10−)
207Fr87120206.996941(19)14.8(1) sα (95%)203At9/2−
β+ (5%)207Rn
208Fr87121207.997139(13)59.1(3) sα (90%)204At7+
β+ (10%)208Rn
209Fr87122208.995940(12)50.0(3) sα (89%)205At9/2−
β+ (11%)209Rn
210Fr87123209.996411(14)3.18(6) minα (60%)206At6+
β+ (40%)210Rn
211Fr87124210.995555(13)3.10(2) minα (80%)207At9/2−
β+ (20%)211Rn
212Fr87125211.996225(9)20.0(6) minβ+ (57%)212Rn5+
α (43%)208At
213Fr87126212.996184(5)34.14(6) s [3] 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+)
215Fr87128215.000342(8)86(5) nsα211At9/2−
216Fr87129216.003190(4)0.70(2) μsα212At(1−)
216mFr219(6) keV850(30) nsα [n 7] 212At(9−)
217Fr87130217.004632(7)16.8(19) μsα213At9/2−
218Fr87131218.007579(5)1.0(6) msα214At1−
218m1Fr86(4) keV22.0(5) msα214At(8−)
218m2Fr200(150)# keVhigh
219Fr87132219.009251(7)20(2) msα215At9/2−
220Fr87133220.012327(4)27.4(3) sα (99.65%)216At1+
β− (.35%)220Ra
221Fr87134221.014254(5)4.801(5) minα (99.9%)217At5/2−Trace [n 8]
β− (.1%)221Ra
CD (8.79×10−11%) [n 9] 207Tl
14C
222Fr87135222.017583(8)14.2(3) minβ−222Ra2−
223FrActinium K87136223.0197342(21)22.00(7) minβ− (99.99%)223Ra3/2(−)Trace [n 10]
α (.006%)219At
224Fr87137224.023348(12)3.33(10) minβ−224Ra1−
225Fr87138225.025572(13)4.0(2) minβ−225Ra3/2−
226Fr87139226.029545(7)49(1) sβ−226Ra1−
227Fr87140227.031865(6)2.47(3) minβ−227Ra1/2+
228Fr87141228.035839(7)38(1) sβ−228Ra2−
229Fr87142229.038291(5)50.2(4) sβ−229Ra(1/2+)#
230Fr87143230.042391(7)19.1(5) sβ−230Ra
231Fr87144231.045175(8)17.6(6) sβ−231Ra(1/2+)#
232Fr87145232.049461(15)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

Related Research Articles

Protactinium (91Pa) has no stable isotopes. The four naturally occurring isotopes allow a standard atomic weight to be given.

There are 39 known isotopes of radon (86Rn), from 193Rn to 231Rn; all are radioactive. The most stable isotope is 222Rn with a half-life of 3.8235 days, which decays into 218
Po
. Six isotopes of radon, 217, 218, 219, 220, 221, 222Rn, occur in trace quantities in nature as decay products of, respectively, 217At, 218At, 223Ra, 224Ra, 225Ra, and 226Ra. 217Rn and 221Rn are produced in rare branches in the decay chain of trace quantities of 237Np; 222Rn is an intermediate step in the decay chain of 238U; 219Rn is an intermediate step in the decay chain of 235U; and 220Rn occurs in the decay chain of 232Th.

Astatine (85At) has 41 known isotopes, all of which are radioactive; their mass numbers range from 188 to 229. There are also 24 known metastable excited states. The longest-lived isotope is 210At, which has a half-life of 8.1 hours; the longest-lived isotope existing in naturally occurring decay chains is 219At with a half-life of 56 seconds.

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.

Bismuth (83Bi) has 41 known isotopes, ranging from 184Bi to 224Bi. Bismuth has no stable isotopes, but does have one very long-lived isotope; thus, the standard atomic weight can be given as 208.98040(1). Although bismuth-209 is now known to be radioactive, it has classically been considered to be a stable isotope because it has a half-life of approximately 2.01×1019 years, which is more than a billion times the age of the universe. Besides 209Bi, the most stable bismuth radioisotopes are 210mBi with a half-life of 3.04 million years, 208Bi with a half-life of 368,000 years and 207Bi, with a half-life of 32.9 years, none of which occurs in nature. All other isotopes have half-lives under 1 year, most under a day. Of naturally occurring radioisotopes, the most stable is radiogenic 210Bi with a half-life of 5.012 days. 210mBi is unusual for being a nuclear isomer with a half-life multiple orders of magnitude longer than that of the ground state.

<span class="mw-page-title-main">Isotopes of thallium</span>

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 erbium (68Er) is composed of six stable isotopes, with 166Er being the most abundant. Thirty-nine radioisotopes have been characterized with between 74 and 112 neutrons, or 142 to 180 nucleons, with the most stable being 169Er with a half-life of 9.4 days, 172Er with a half-life of 49.3 hours, 160Er with a half-life of 28.58 hours, 165Er with a half-life of 10.36 hours, and 171Er with a half-life of 7.516 hours. All of the remaining radioactive isotopes have half-lives that are less than 3.5 hours, and the majority of these have half-lives that are less than 4 minutes. This element also has numerous meta states, with the most stable being 167mEr.

<span class="mw-page-title-main">Isotopes of holmium</span>

Natural holmium (67Ho) contains one observationally stable isotope, 165Ho. The below table lists 39 isotopes spanning 140Ho through 178Ho as well as 40 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 six 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.

Antimony (51Sb) occurs in two stable isotopes, 121Sb and 123Sb. There are 37 artificial radioactive isotopes, the longest-lived of which are 125Sb, with a half-life of 2.75856 years; 124Sb, with half-life 60.2 days; and 126Sb, with half-life 12.35 days. All other isotopes have half-lives less than 4 days, most less than an hour. There are also many isomers, the longest-lived of which is 120m1Sb with half-life 5.76 days.

Tin (50Sn) is the element with the greatest number of stable isotopes. This is probably related to the fact that 50 is a "magic number" of protons. In addition, twenty-nine unstable tin isotopes are known, including tin-100 (100Sn) and tin-132 (132Sn), which are both "doubly magic". The longest-lived tin radioisotope is tin-126 (126Sn), with a half-life of 230,000 years. The other 28 radioisotopes have half-lives of less than a year.

Naturally occurring rhodium (45Rh) is composed of only one stable isotope, 103Rh. The most stable radioisotopes are 101Rh with a half-life of 3.3 years, 102Rh with a half-life of 207 days, and 99Rh with a half-life of 16.1 days. Thirty other radioisotopes have been characterized with atomic weights ranging from 88.949 u (89Rh) to 121.943 u (122Rh). Most of these have half-lives that are less than an hour except 100Rh and 105Rh. There are also numerous meta states with the most stable being 102mRh (0.141 MeV) with a half-life of about 3.7 years and 101mRh (0.157 MeV) with a half-life of 4.34 days.

Arsenic (33As) has 32 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.

Naturally occurring scandium (21Sc) is composed of one stable isotope, 45Sc. Twenty-seven 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.

Curium (96Cm) is an artificial element with an atomic number of 96. Because it is an artificial element, a standard atomic weight cannot be given, and it has no stable isotopes. The first isotope synthesized was 242Cm in 1944, which has 146 neutrons.

Berkelium (97Bk) is an artificial element, and thus a standard atomic weight cannot be given. Like all artificial elements, it has no stable isotopes. The first isotope to be synthesized was 243Bk in 1949. There are twenty known radioisotopes, from 233Bk and 233Bk to 253Bk, and six nuclear isomers. The longest-lived isotope is 247Bk with a half-life of 1,380 years.

Fermium (100Fm) is a synthetic element, and thus a standard atomic weight cannot be given. Like all artificial elements, it has no stable isotopes. The first isotope to be discovered was 255Fm in 1952. 250Fm was independently synthesized shortly after the discovery of 255Fm. There are 20 known radioisotopes ranging in atomic mass from 241Fm to 260Fm, and 4 nuclear isomers, 247mFm, 250mFm, 251mFm, and 253mFm. The longest-lived isotope is 257Fm with a half-life of 100.5 days, and the longest-lived isomer is 247mFm with a half-life of 5.1 seconds.

Mendelevium (101Md) is a synthetic element, and thus a standard atomic weight cannot be given. Like all artificial elements, it has no stable isotopes. The first isotope to be synthesized was 256Md in 1955. There are 17 known radioisotopes, ranging in atomic mass from 244Md to 260Md, and 5 isomers. The longest-lived isotope is 258Md with a half-life of 51.3 days, and the longest-lived isomer is 258mMd with a half-life of 57 minutes.

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. ↑ Wang, Meng; Huang, W.J.; Kondev, F.G.; Audi, G.; Naimi, S. (2021). "The AME 2020 atomic mass evaluation (II). Tables, graphs and references*". Chinese Physics C. 45 (3): 030003. doi:10.1088/1674-1137/abddaf.
  3. ↑ 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.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.