Isotopes of francium explained

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

|-| ¹⁹⁷Fr|| style="text-align:right" | 87| style="text-align:right" | 110| 197.01101(6)| 2.3(19) ms| α| ¹⁹³At| (7/2−)||-| ¹⁹⁸Fr|| style="text-align:right" | 87| style="text-align:right" | 111| 198.01028(3)| 15(3) ms| α| ¹⁹⁴At| 3+#||-| ¹⁹⁹Fr|| style="text-align:right" | 87| style="text-align:right" | 112| 199.00726(4)| 16(7) ms| α| ¹⁹⁵At| 1/2+#||-| ²⁰⁰Fr|| style="text-align:right" | 87| style="text-align:right" | 113| 200.00657(8)| 24(10) ms| α| ¹⁹⁶At| 3+#||-| style="text-indent:1em" | ^200mFr| | colspan="3" style="text-indent:2em" | 60(110) keV| 190(120) ms| α| ¹⁹⁶At| 10−#||-| rowspan=2|²⁰¹Fr| rowspan=2|| rowspan=2 style="text-align:right" | 87| rowspan=2 style="text-align:right" | 114| rowspan=2|201.00386(8)| rowspan=2|67(3) ms| α (99%)| ¹⁹⁷At| rowspan=2|(9/2−)| rowspan=2||-| β⁺ (1%)| ²⁰¹Rn|-| rowspan=2|²⁰²Fr| rowspan=2|| rowspan=2 style="text-align:right" | 87| rowspan=2 style="text-align:right" | 115| rowspan=2|202.00337(5)| rowspan=2|290(30) ms| α (97%)| ¹⁹⁸At| rowspan=2|(3+)| rowspan=2||-| β⁺ (3%)| ²⁰²Rn|-| rowspan=2 style="text-indent:1em" | ^202mFr| rowspan=2|| rowspan=2 colspan="3" style="text-indent:2em" | 330(90)# keV| rowspan=2|340(40) ms| α (97%)| ¹⁹⁸At| rowspan=2|(10−)| rowspan=2||-| β⁺ (3%)| ²⁰²Rn|-| rowspan=2|²⁰³Fr| rowspan=2|| rowspan=2 style="text-align:right" | 87| rowspan=2 style="text-align:right" | 116| rowspan=2|203.000925(17)| rowspan=2|0.55(2) s| α (95%)| ¹⁹⁹At| rowspan=2|(9/2−)#| rowspan=2||-| β⁺ (5%)| ²⁰³Rn|-| rowspan=2|²⁰⁴Fr| rowspan=2|| rowspan=2 style="text-align:right" | 87| rowspan=2 style="text-align:right" | 117| rowspan=2|204.000653(26)| rowspan=2|1.7(3) s| α (96%)| ²⁰⁰At| rowspan=2|(3+)| rowspan=2||-| β⁺ (4%)| ²⁰⁴Rn|-| rowspan=2 style="text-indent:1em" | ^204m1Fr| rowspan=2|| rowspan=2 colspan="3" style="text-indent:2em" | 50(4) keV| rowspan=2|2.6(3) s| α (90%)| ²⁰⁰At| rowspan=2|(7+)| rowspan=2||-| β⁺ (10%)| ²⁰⁴Rn|-| style="text-indent:1em" | ^204m2Fr| | colspan="3" style="text-indent:2em" | 326(4) keV| 1.7(6) s||| (10−)| |-| rowspan=2|²⁰⁵Fr| rowspan=2|| rowspan=2 style="text-align:right" | 87| rowspan=2 style="text-align:right" | 118| rowspan=2|204.998594(8)| rowspan=2|3.80(3) s| α (99%)| ²⁰¹At| rowspan=2|(9/2−)| rowspan=2||-| β⁺ (1%)| ²⁰⁵Rn|-| rowspan=2|²⁰⁶Fr| rowspan=2|| rowspan=2 style="text-align:right" | 87| rowspan=2 style="text-align:right" | 119| rowspan=2|205.99867(3)| rowspan=2|~16 s| β⁺ (58%)| ²⁰⁶Rn| rowspan=2|(2+, 3+)| rowspan=2||-| α (42%)| ²⁰²At|-| style="text-indent:1em" | ^206m1Fr| | colspan="3" style="text-indent:2em" | 190(40) keV| 15.9(1) s||| (7+)||-| style="text-indent:1em" | ^206m2Fr|| colspan="3" style="text-indent:2em" | 730(40) keV| 700(100) ms||| (10−)||-| rowspan=2|²⁰⁷Fr| rowspan=2|| rowspan=2 style="text-align:right" | 87| rowspan=2 style="text-align:right" | 120| rowspan=2|206.99695(5)| rowspan=2|14.8(1) s| α (95%)| ²⁰³At| rowspan=2|9/2−| rowspan=2||-| β⁺ (5%)| ²⁰⁷Rn|-| rowspan=2|²⁰⁸Fr| rowspan=2|| rowspan=2 style="text-align:right" | 87| rowspan=2 style="text-align:right" | 121| rowspan=2|207.99714(5)| rowspan=2|59.1(3) s| α (90%)| ²⁰⁴At| rowspan=2|7+| rowspan=2||-| β⁺ (10%)| ²⁰⁸Rn|-| rowspan=2|²⁰⁹Fr| rowspan=2|| rowspan=2 style="text-align:right" | 87| rowspan=2 style="text-align:right" | 122| rowspan=2|208.995954(16)| rowspan=2|50.0(3) s| α (89%)| ²⁰⁵At| rowspan=2|9/2−| rowspan=2||-| β⁺ (11%)| ²⁰⁹Rn|-| rowspan=2|²¹⁰Fr| rowspan=2|| rowspan=2 style="text-align:right" | 87| rowspan=2 style="text-align:right" | 123| rowspan=2|209.996408(24)| rowspan=2|3.18(6) min| α (60%)| ²⁰⁶At| rowspan=2|6+| rowspan=2||-| β⁺ (40%)| ²¹⁰Rn|-| rowspan=2|²¹¹Fr| rowspan=2|| rowspan=2 style="text-align:right" | 87| rowspan=2 style="text-align:right" | 124| rowspan=2|210.995537(23)| rowspan=2|3.10(2) min| α (80%)| ²⁰⁷At| rowspan=2|9/2−| rowspan=2||-| β⁺ (20%)| ²¹¹Rn|-| rowspan=2|²¹²Fr| rowspan=2|| rowspan=2 style="text-align:right" | 87| rowspan=2 style="text-align:right" | 125| rowspan=2|211.996202(28)| rowspan=2|20.0(6) min| β⁺ (57%)| ²¹²Rn| rowspan=2|5+| rowspan=2||-| α (43%)| ²⁰⁸At|-| rowspan=2|²¹³Fr| rowspan=2|| rowspan=2 style="text-align:right" | 87| rowspan=2 style="text-align:right" | 126| rowspan=2|212.996189(8)| rowspan=2|34.14(6) s^[1] | α (99.45%)| ²⁰⁹At| rowspan=2|9/2−| rowspan=2||-| β⁺ (.55%)| ²¹³Rn|-| ²¹⁴Fr|| style="text-align:right" | 87| style="text-align:right" | 127| 213.998971(9)| 5.0(2) ms| α| ²¹⁰At| (1−)||-| style="text-indent:1em" | ^214m1Fr|| colspan="3" style="text-indent:2em" | 123(6) keV| 3.35(5) ms| α| ²¹⁰At| (8−)||-| style="text-indent:1em" | ^214m2Fr|| colspan="3" style="text-indent:2em" | 638(6) keV| 103(4) ns||| (11+)||-| style="text-indent:1em" | ^214m3Fr|| colspan="3" style="text-indent:2em" | 6477+Y keV| 108(7) ns||| (33+)||-| ²¹⁵Fr|| style="text-align:right" | 87| style="text-align:right" | 128| 215.000341(8)| 86(5) ns| α| ²¹¹At| 9/2−||-|²¹⁶Fr|| style="text-align:right" | 87| style="text-align:right" | 129|216.003198(15)|0.70(2) μs| α| ²¹²At|(1−)||-| style="text-indent:1em" | ^216mFr|| colspan="3" style="text-indent:2em" | 219(6) keV| 850(30) ns| α| ²¹²At| (9−)||-| ²¹⁷Fr|| style="text-align:right" | 87| style="text-align:right" | 130| 217.004632(7)| 16.8(19) μs| α| ²¹³At| 9/2−||-| ²¹⁸Fr|| style="text-align:right" | 87| style="text-align:right" | 131| 218.007578(5)| 1.0(6) ms| α| ²¹⁴At| 1−||-|style="text-indent:1em" | ^218m1Fr|| colspan="3" style="text-indent:2em" | 86(4) keV| 22.0(5) ms| α| ²¹⁴At| (8−)||-| style="text-indent:1em" | ^218m2Fr|| colspan="3" style="text-indent:2em" | 200(150)# keV|||| high||-| ²¹⁹Fr|| style="text-align:right" | 87| style="text-align:right" | 132| 219.009252(8)| 20(2) ms| α| ²¹⁵At| 9/2−||-| rowspan=2|²²⁰Fr| rowspan=2|| rowspan=2 style="text-align:right" | 87| rowspan=2 style="text-align:right" | 133| rowspan=2|220.012327(4)| rowspan=2|27.4(3) s| α (99.65%)| ²¹⁶At| rowspan=2|1+| rowspan=2||-| β⁻ (.35%)| ²²⁰Ra|-| rowspan=3|²²¹Fr| rowspan=3|| rowspan=3 style="text-align:right" | 87| rowspan=3 style="text-align:right" | 134| rowspan=3|221.014255(5)| rowspan=3|4.9(2) min| α (99.9%)| ²¹⁷At| rowspan=3|5/2−| rowspan=3|Trace^[2] |-| β⁻ (.1%)| ²²¹Ra|-| CD (8.79×10⁻¹¹%)^[3] | ²⁰⁷Tl
¹⁴C|-| ²²²Fr|| style="text-align:right" | 87| style="text-align:right" | 135| 222.017552(23)| 14.2(3) min| β⁻| ²²²Ra| 2−||-| rowspan=2|²²³Fr| rowspan=2|Actinium K| rowspan=2 style="text-align:right" | 87| rowspan=2 style="text-align:right" | 136| rowspan=2|223.0197359(26)| rowspan=2|22.00(7) min| β⁻ (99.99%)| ²²³Ra| rowspan=2|3/2(−)| rowspan=2|Trace^[4] |-| α (.006%)| ²¹⁹At|-| ²²⁴Fr|| style="text-align:right" | 87| style="text-align:right" | 137| 224.02325(5)| 3.33(10) min| β⁻| ²²⁴Ra| 1−||-| ²²⁵Fr|| style="text-align:right" | 87| style="text-align:right" | 138| 225.02557(3)| 4.0(2) min| β⁻| ²²⁵Ra| 3/2−||-| ²²⁶Fr|| style="text-align:right" | 87| style="text-align:right" | 139| 226.02939(11)| 49(1) s| β⁻| ²²⁶Ra| 1−||-| ²²⁷Fr|| style="text-align:right" | 87| style="text-align:right" | 140| 227.03184(11)| 2.47(3) min| β⁻| ²²⁷Ra| 1/2+||-| ²²⁸Fr|| style="text-align:right" | 87| style="text-align:right" | 141| 228.03573(22)#| 38(1) s| β⁻| ²²⁸Ra| 2−||-| ²²⁹Fr|| style="text-align:right" | 87| style="text-align:right" | 142| 229.03845(4)| 50.2(4) s| β⁻| ²²⁹Ra| (1/2+)#||-| ²³⁰Fr|| style="text-align:right" | 87| style="text-align:right" | 143| 230.04251(48)#| 19.1(5) s| β⁻| ²³⁰Ra|||-| ²³¹Fr|| style="text-align:right" | 87| style="text-align:right" | 144| 231.04544(50)#| 17.6(6) s| β⁻| ²³¹Ra| (1/2+)#||-| ²³²Fr|| style="text-align:right" | 87| style="text-align:right" | 145| 232.04977(69)#| 5(1) s| β⁻| ²³²Ra|||-| ²³³Fr|| style="text-align:right" | 87| style="text-align:right" | 146| 233.052518(21)| 900(100) ms| β⁻| ²³³Ra| 1/2+ #|

References

1. 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. . Determination of the half-life of ²¹³Fr with high precision . Physical Review C . American Physical Society (APS) . 88 . 1 . 2013-07-24 . 011303 . 0556-2813 . 10.1103/physrevc.88.011303. 2013PhRvC..88a1303F .
2. Intermediate decay product of ²³⁷Np
3. The nuclide with the lowest atomic number known to undergo cluster decay
4. Intermediate decay product of ²³⁵U

• Isotope masses from:
  • • Half-life, spin, and isomer data selected from the following sources.