Isotopes of francium

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
 * 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
 * β− (.1%)
 * 221Ra
 * CD (8.79×10−11%)
 * 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
 * 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+ #
 * α (99.9%)
 * 217At
 * rowspan=3|5/2−
 * rowspan=3|Trace
 * β− (.1%)
 * 221Ra
 * CD (8.79×10−11%)
 * 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
 * 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+ #
 * 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+ #
 * 233Fr
 * style="text-align:right" | 87
 * style="text-align:right" | 146
 * 233.052518(21)
 * 900(100) ms
 * β−
 * 233Ra
 * 1/2+ #
 * β−
 * 233Ra
 * 1/2+ #