Isotopes of francium
Encyclopedia
Francium
(Fr) has no stable isotopes. A standard atomic mass
cannot be given. Its most stable isotope is 223Fr with a half-life of 22 minutes, which is also the only naturally occurring isotope, occurring in trace quantities 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 greater than or equal to 106 (Seaborgium
) have most-stable-known isotopes shorter than that of Francium, but those elements have only a relatively small number of isotopes discovered, thus, there is the possibility of a yet-unknown isotope having a longer half-life.
Francium
Francium is a chemical element with symbol Fr and atomic number 87. It was formerly known as eka-caesium and actinium K.Actually the least unstable isotope, francium-223 It has the lowest electronegativity of all known elements, and is the second rarest naturally occurring element...
(Fr) has no stable isotopes. A standard atomic mass
Atomic mass
The atomic mass is the mass of a specific isotope, most often expressed in unified atomic mass units. The atomic mass is the total mass of protons, neutrons and electrons in a single atom....
cannot be given. Its most stable isotope is 223Fr with a half-life of 22 minutes, which is also the only naturally occurring isotope, occurring in trace quantities as an intermediate decay product
Decay product
In nuclear physics, a decay product is the remaining nuclide left over from radioactive decay. Radioactive decay often involves a sequence of steps...
of 235U
Uranium-235
- References :* .* DOE Fundamentals handbook: Nuclear Physics and Reactor theory , .* A piece of U-235 the size of a grain of rice can produce energy equal to that contained in three tons of coal or fourteen barrels of oil. -External links:* * * one of the earliest articles on U-235 for the...
.
Of elements whose most stable isotopes have been identified with certainty, Francium is the most unstable. All elements with atomic number of greater than or equal to 106 (Seaborgium
Seaborgium
Seaborgium is a synthetic chemical element with the symbol Sg and atomic number 106.Seaborgium is a synthetic element whose most stable isotope 271Sg has a half-life of 1.9 minutes. A new isotope 269Sg has a potentially slightly longer half-life based on the observation of a single decay...
) have most-stable-known isotopes shorter than that of Francium, but those elements have only a relatively small number of isotopes discovered, thus, there is the possibility of a yet-unknown isotope having a longer half-life.
Table
| nuclide symbol |
historic name |
Z(p Proton The proton is a subatomic particle with the symbol or and a positive electric charge of 1 elementary charge. One or more protons are present in the nucleus of each atom, along with neutrons. The number of protons in each atom is its atomic number.... ) |
N(n Neutron The neutron is a subatomic hadron particle which has the symbol or , no net electric charge and a mass slightly larger than that of a proton. With the exception of hydrogen, nuclei of atoms consist of protons and neutrons, which are therefore collectively referred to as nucleons. The number of... ) |
isotopic mass (u) |
half-life | decay mode(s)Abbreviations: CD: Cluster decay Cluster decay Cluster decay is a type of nuclear decay in which a parent atomic nucleus with A nucleons and Z protons emits a cluster of Ne neutrons and Ze protons heavier than an alpha particle but lighter than a typical binary fission fragment Cluster decay (also named heavy particle radioactivity or heavy... IT: Isomeric transition Isomeric transition An isomeric transition is a radioactive decay process that involves emission of a gamma ray from an atom where the nucleus is in an excited metastable state, referred to in its excited state, as a nuclear isomer.... |
daughter isotope(s) |
nuclear spin |
representative isotopic composition (mole fraction) |
range of natural variation (mole fraction) |
|---|---|---|---|---|---|---|---|---|---|---|
| excitation energy | ||||||||||
| 199Fr | 87 | 112 | 199.00726(4) | 16(7) ms | 1/2+# | |||||
| 200Fr | 87 | 113 | 200.00657(8) | 24(10) ms | α Alpha decay Alpha decay is a type of radioactive decay in which an atomic nucleus emits an alpha particle and thereby transforms into an atom with a mass number 4 less and atomic number 2 less... |
196At | 3+# | |||
| 200mFr | 60(110) keV | 650(210) ms | α | 196At | 10-# | |||||
| IT Isomeric transition An isomeric transition is a radioactive decay process that involves emission of a gamma ray from an atom where the nucleus is in an excited metastable state, referred to in its excited state, as a nuclear isomer.... (rare) |
200Fr | |||||||||
| 201Fr | 87 | 114 | 201.00386(8) | 67(3) ms | α (99%) | 197At | (9/2-) | |||
| β+ (1%) | 201Rn | |||||||||
| 202Fr | 87 | 115 | 202.00337(5) | 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 | 203.000925(17) | 0.55(2) s | α (95%) | 199At | (9/2-)# | |||
| β+ (5%) | 203Rn | |||||||||
| 204Fr | 87 | 117 | 204.000653(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 | 205.99867(3) | ~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 | 206.99695(5) | 14.8(1) s | α (95%) | 203At | 9/2- | |||
| β+ (5%) | 207Rn | |||||||||
| 208Fr | 87 | 121 | 207.99714(5) | 59.1(3) s | α (90%) | 204At | 7+ | |||
| β+ (10%) | 208Rn | |||||||||
| 209Fr | 87 | 122 | 208.995954(16) | 50.0(3) s | α (89%) | 205At | 9/2- | |||
| β+ (11%) | 209Rn | |||||||||
| 210Fr | 87 | 123 | 209.996408(24) | 3.18(6) min | α (60%) | 206At | 6+ | |||
| β+ (40%) | 210Rn | |||||||||
| 211Fr | 87 | 124 | 210.995537(23) | 3.10(2) min | α (80%) | 207At | 9/2- | |||
| β+ (20%) | 211Rn | |||||||||
| 212Fr | 87 | 125 | 211.996202(28) | 20.0(6) min | β+ (57%) | 212Rn | 5+ | |||
| α (43%) | 208At | |||||||||
| 213Fr | 87 | 126 | 212.996189(8) | 34.6(3) s | 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 | 215.000341(8) | 86(5) ns | α | 211At | 9/2- | |||
| 216Fr | 87 | 129 | 216.003198(15) | 0.70(2) µs | α | 212At | (1-) | |||
| β+ (2×10−7%) | 216Rn | |||||||||
| 217Fr | 87 | 130 | 217.004632(7) | 16.8(19) µs | α | 213At | 9/2- | |||
| 218Fr | 87 | 131 | 218.007578(5) | 1.0(6) ms | α | 214At | 1- | |||
| 218m1Fr | 86(4) keV | 22.0(5) ms | α | 214At | ||||||
| IT (rare) | 218Fr | |||||||||
| 218m2Fr | 200(150)# keV | high | ||||||||
| 219Fr | 87 | 132 | 219.009252(8) | 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 | 221.014255(5) | 4.9(2) min | α (99.9%) | 217At | 5/2- | |||
| β- (.1%) | 221Ra | |||||||||
| CD Cluster decay Cluster decay is a type of nuclear decay in which a parent atomic nucleus with A nucleons and Z protons emits a cluster of Ne neutrons and Ze protons heavier than an alpha particle but lighter than a typical binary fission fragment Cluster decay (also named heavy particle radioactivity or heavy... (8.79×−11%) |
207Tl 14C Carbon-14 Carbon-14, 14C, or radiocarbon, is a radioactive isotope of carbon with a nucleus containing 6 protons and 8 neutrons. Its presence in organic materials is the basis of the radiocarbon dating method pioneered by Willard Libby and colleagues , to date archaeological, geological, and hydrogeological... |
|||||||||
| 222Fr | 87 | 135 | 222.017552(23) | 14.2(3) min | β- | 222Ra | 2- | |||
| 223Fr | Actinium K | 87 | 136 | 223.0197359(26) | 22.00(7) min | β- (99.99%) | 223Ra | 3/2(-) | TraceIntermediate decay product Decay product In nuclear physics, a decay product is the remaining nuclide left over from radioactive decay. Radioactive decay often involves a sequence of steps... of 235U Uranium-235 - References :* .* DOE Fundamentals handbook: Nuclear Physics and Reactor theory , .* A piece of U-235 the size of a grain of rice can produce energy equal to that contained in three tons of coal or fourteen barrels of oil. -External links:* * * one of the earliest articles on U-235 for the... |
|
| α (.006%) | 219At | |||||||||
| 224Fr | 87 | 137 | 224.02325(5) | 3.33(10) min | β- | 224Ra | 1- | |||
| 225Fr | 87 | 138 | 225.02557(3) | 4.0(2) min | β- | 225Ra | 3/2- | |||
| 226Fr | 87 | 139 | 226.02939(11) | 49(1) s | β- | 226Ra | 1- | |||
| 227Fr | 87 | 140 | 227.03184(11) | 2.47(3) min | β- | 227Ra | 1/2+ | |||
| 228Fr | 87 | 141 | 228.03573(22)# | 38(1) s | β- | 228Ra | 2- | |||
| 229Fr | 87 | 142 | 229.03845(4) | 50.2(4) s | β- | 229Ra | (1/2+)# | |||
| 230Fr | 87 | 143 | 230.04251(48)# | 19.1(5) s | β- | 230Ra | ||||
| 231Fr | 87 | 144 | 231.04544(50)# | 17.6(6) s | β- | 231Ra | (1/2+)# | |||
| 232Fr | 87 | 145 | 232.04977(69)# | 5(1) s | β- | 232Ra | ||||