Isotopes of francium

(Redirected from Francium-224)

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.

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
222Fr synth 14.2 min β 222Ra
223Fr trace 22.00 min β 223Ra
α 219At

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

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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]
197Fr 87 110 197.01101(6) 2.3(19) ms α 193At (7/2−)
198Fr 87 111 198.01028(3) 15(3) ms α 194At 3+#
199Fr 87 112 199.007269(15) 16(7) ms α 195At 1/2+#
200Fr 87 113 200.00658(3) 24(10) ms α 196At 3+#
200mFr 60(110) keV 190(120) ms α 196At 10−#
201Fr 87 114 201.003852(10) 67(3) ms α (99%) 197At (9/2−)
β+ (1%) 201Rn
202Fr 87 115 202.003330(6) 290(30) ms α (97%) 198At (3+)
β+ (3%) 202Rn
202mFr 330(90)# keV 340(40) ms α (97%) 198At (10−)
β+ (3%) 202Rn
203Fr 87 116 203.000941(7) 0.55(2) s α (95%) 199At (9/2−)#
β+ (5%) 203Rn
204Fr 87 117 204.000652(26) 1.7(3) s α (96%) 200At (3+)
β+ (4%) 204Rn
204m1Fr 50(4) keV 2.6(3) s α (90%) 200At (7+)
β+ (10%) 204Rn
204m2Fr 326(4) keV 1.7(6) s (10−)
205Fr 87 118 204.998594(8) 3.80(3) s α (99%) 201At (9/2−)
β+ (1%) 205Rn
206Fr 87 119 205.998661(30) ~16 s β+ (58%) 206Rn (2+, 3+)
α (42%) 202At
206m1Fr 190(40) keV 15.9(1) s (7+)
206m2Fr 730(40) keV 700(100) ms (10−)
207Fr 87 120 206.996941(19) 14.8(1) s α (95%) 203At 9/2−
β+ (5%) 207Rn
208Fr 87 121 207.997139(13) 59.1(3) s α (90%) 204At 7+
β+ (10%) 208Rn
209Fr 87 122 208.995940(12) 50.0(3) s α (89%) 205At 9/2−
β+ (11%) 209Rn
210Fr 87 123 209.996411(14) 3.18(6) min α (60%) 206At 6+
β+ (40%) 210Rn
211Fr 87 124 210.995555(13) 3.10(2) min α (80%) 207At 9/2−
β+ (20%) 211Rn
212Fr 87 125 211.996225(9) 20.0(6) min β+ (57%) 212Rn 5+
α (43%) 208At
213Fr 87 126 212.996184(5) 34.14(6) s[3] α (99.45%) 209At 9/2−
β+ (.55%) 213Rn
214Fr 87 127 213.998971(9) 5.0(2) ms α 210At (1−)
214m1Fr 123(6) keV 3.35(5) ms α 210At (8−)
214m2Fr 638(6) keV 103(4) ns (11+)
214m3Fr 6477+Y keV 108(7) ns (33+)
215Fr 87 128 215.000342(8) 86(5) ns α 211At 9/2−
216Fr 87 129 216.003190(4) 0.70(2) μs α 212At (1−)
216mFr 219(6) keV 850(30) ns α[n 7] 212At (9−)
217Fr 87 130 217.004632(7) 16.8(19) μs α 213At 9/2−
218Fr 87 131 218.007579(5) 1.0(6) ms α 214At 1−
218m1Fr 86(4) keV 22.0(5) ms α 214At (8−)
218m2Fr 200(150)# keV high
219Fr 87 132 219.009251(7) 20(2) ms α 215At 9/2−
220Fr 87 133 220.012327(4) 27.4(3) s α (99.65%) 216At 1+
β (.35%) 220Ra
221Fr 87 134 221.014254(5) 4.9(2) min α (99.9%) 217At 5/2− Trace[n 8]
β (.1%) 221Ra
CD (8.79×10−11%)[n 9] 207Tl
14C
222Fr 87 135 222.017583(8) 14.2(3) min β 222Ra 2−
223Fr Actinium K 87 136 223.0197342(21) 22.00(7) min β (99.99%) 223Ra 3/2(−) Trace[n 10]
α (.006%) 219At
224Fr 87 137 224.023348(12) 3.33(10) min β 224Ra 1−
225Fr 87 138 225.025572(13) 4.0(2) min β 225Ra 3/2−
226Fr 87 139 226.029545(7) 49(1) s β 226Ra 1−
227Fr 87 140 227.031865(6) 2.47(3) min β 227Ra 1/2+
228Fr 87 141 228.035839(7) 38(1) s β 228Ra 2−
229Fr 87 142 229.038291(5) 50.2(4) s β 229Ra (1/2+)#
230Fr 87 143 230.042391(7) 19.1(5) s β 230Ra
231Fr 87 144 231.045175(8) 17.6(6) s β 231Ra (1/2+)#
232Fr 87 145 232.049461(15) 5(1) s β 232Ra
233Fr 87 146 233.052518(21) 900(100) ms β 233Ra 1/2+ #
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. ^ a b c # – 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

References

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  1. ^ a b 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.