Isotopes of krypton
Encyclopedia
There are 33 known isotope
s of krypton
(Kr) from 69 to 101. Naturally occurring krypton is made of six stable
isotopes, two of which may be slightly radioactive. Its spectral signature can be produced with some very sharp lines. 81Kr, the product of atmospheric reactions is produced with the other naturally occurring isotope
s of krypton. It is radioactive with a half-life
of 229,000 years. Krypton is highly volatile when it is near surface waters and 81Kr has been used for dating old (50,000 - 800,000 year) groundwater
.
85Kr
is an inert radioactive noble gas with a half-life of 10.76 years. It is produced by fission
of uranium
and plutonium
in nuclear bomb testing and nuclear reactor
s. It is released during the reprocessing of fuel rods from nuclear reactors. Concentrations at the North Pole
are 30% higher than at the South Pole
as most nuclear reactors are in the northern hemisphere. All other isotopes have half-lives under a day, except 79Kr with a half-life of 35.04 10 hours.
Standard atomic mass: 83.798(2) u
Isotope
Isotopes are variants of atoms of a particular chemical element, which have differing numbers of neutrons. Atoms of a particular element by definition must contain the same number of protons but may have a distinct number of neutrons which differs from atom to atom, without changing the designation...
s of krypton
Krypton
Krypton is a chemical element with the symbol Kr and atomic number 36. It is a member of Group 18 and Period 4 elements. A colorless, odorless, tasteless noble gas, krypton occurs in trace amounts in the atmosphere, is isolated by fractionally distilling liquified air, and is often used with other...
(Kr) from 69 to 101. Naturally occurring krypton is made of six stable
Stable isotope
Stable isotopes are chemical isotopes that may or may not be radioactive, but if radioactive, have half-lives too long to be measured.Only 90 nuclides from the first 40 elements are energetically stable to any kind of decay save proton decay, in theory...
isotopes, two of which may be slightly radioactive. Its spectral signature can be produced with some very sharp lines. 81Kr, the product of atmospheric reactions is produced with the other naturally occurring isotope
Isotope
Isotopes are variants of atoms of a particular chemical element, which have differing numbers of neutrons. Atoms of a particular element by definition must contain the same number of protons but may have a distinct number of neutrons which differs from atom to atom, without changing the designation...
s of krypton. It is radioactive with a half-life
Half-life
Half-life, abbreviated t½, is the period of time it takes for the amount of a substance undergoing decay to decrease by half. The name was originally used to describe a characteristic of unstable atoms , but it may apply to any quantity which follows a set-rate decay.The original term, dating to...
of 229,000 years. Krypton is highly volatile when it is near surface waters and 81Kr has been used for dating old (50,000 - 800,000 year) groundwater
Groundwater
Groundwater is water located beneath the ground surface in soil pore spaces and in the fractures of rock formations. A unit of rock or an unconsolidated deposit is called an aquifer when it can yield a usable quantity of water. The depth at which soil pore spaces or fractures and voids in rock...
.
85Kr
Krypton-85
Krypton 85 is a radioisotope of krypton.It decays into rubidium-85, with a half-life of 10.756 years and a maximum decay energy of 0.687 MeV.Its most common decay is by beta particle emission with maximum energy of 687...
is an inert radioactive noble gas with a half-life of 10.76 years. It is produced by fission
Nuclear fission
In nuclear physics and nuclear chemistry, nuclear fission is a nuclear reaction in which the nucleus of an atom splits into smaller parts , often producing free neutrons and photons , and releasing a tremendous amount of energy...
of uranium
Uranium
Uranium is a silvery-white metallic chemical element in the actinide series of the periodic table, with atomic number 92. It is assigned the chemical symbol U. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons...
and plutonium
Plutonium
Plutonium is a transuranic radioactive chemical element with the chemical symbol Pu and atomic number 94. It is an actinide metal of silvery-gray appearance that tarnishes when exposed to air, forming a dull coating when oxidized. The element normally exhibits six allotropes and four oxidation...
in nuclear bomb testing and nuclear reactor
Nuclear reactor
A nuclear reactor is a device to initiate and control a sustained nuclear chain reaction. Most commonly they are used for generating electricity and for the propulsion of ships. Usually heat from nuclear fission is passed to a working fluid , which runs through turbines that power either ship's...
s. It is released during the reprocessing of fuel rods from nuclear reactors. Concentrations at the North Pole
North Pole
The North Pole, also known as the Geographic North Pole or Terrestrial North Pole, is, subject to the caveats explained below, defined as the point in the northern hemisphere where the Earth's axis of rotation meets its surface...
are 30% higher than at the South Pole
South Pole
The South Pole, also known as the Geographic South Pole or Terrestrial South Pole, is one of the two points where the Earth's axis of rotation intersects its surface. It is the southernmost point on the surface of the Earth and lies on the opposite side of the Earth from the North Pole...
as most nuclear reactors are in the northern hemisphere. All other isotopes have half-lives under a day, except 79Kr with a half-life of 35.04 10 hours.
Standard atomic mass: 83.798(2) u
Table
| nuclide symbol |
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: EC: Electron capture Electron capture Electron capture is a process in which a proton-rich nuclide absorbs an inner atomic electron and simultaneously emits a neutrino... 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)Bold for stable isotopes, bold italics for nearly-stable isotopes (half-life longer than the age of the universe Age of the universe The age of the universe is the time elapsed since the Big Bang posited by the most widely accepted scientific model of cosmology. The best current estimate of the age of the universe is 13.75 ± 0.13 billion years within the Lambda-CDM concordance model... ) |
nuclear spin |
representative isotopic composition (mole fraction) |
range of natural variation (mole fraction) |
|---|---|---|---|---|---|---|---|---|---|
| excitation energy | |||||||||
| 69Kr | 36 | 33 | 68.96518(43)# | 32(10) ms | β+ Beta decay In nuclear physics, beta decay is a type of radioactive decay in which a beta particle is emitted from an atom. There are two types of beta decay: beta minus and beta plus. In the case of beta decay that produces an electron emission, it is referred to as beta minus , while in the case of a... |
69Br | 5/2-# | ||
| 70Kr | 36 | 34 | 69.95526(41)# | 52(17) ms | β+ | 70Br | 0+ | ||
| 71Kr | 36 | 35 | 70.94963(70) | 100(3) ms | β+ (94.8%) | 71Br | (5/2)- | ||
| β+, p Proton emission Proton emission is a type of radioactive decay in which a proton is ejected from a nucleus. Proton emission can occur from high-lying excited states in a nucleus following a beta decay, in which case the process is known as beta-delayed proton emission, or can occur from the ground state of very... (5.2%) |
70Se | ||||||||
| 72Kr | 36 | 36 | 71.942092(9) | 17.16(18) s | β+ | 72Br | 0+ | ||
| 73Kr | 36 | 37 | 72.939289(7) | 28.6(6) s | β+ (99.32%) | 73Br | 3/2- | ||
| β+, p (.68%) | 72Se | ||||||||
| 73mKr | 433.66(12) keV | 107(10) ns | (9/2+) | ||||||
| 74Kr | 36 | 38 | 73.9330844(22) | 11.50(11) min | β+ | 74Br | 0+ | ||
| 75Kr | 36 | 39 | 74.930946(9) | 4.29(17) min | β+ | 75Br | 5/2+ | ||
| 76Kr | 36 | 40 | 75.925910(4) | 14.8(1) h | β+ | 76Br | 0+ | ||
| 77Kr | 36 | 41 | 76.9246700(21) | 74.4(6) min | β+ | 77Br | 5/2+ | ||
| 78Kr | 36 | 42 | 77.9203648(12) | Observationally StableBelieved to decay by β+β+ to 78Se with a half-life of more than >1.1×1020 years | 0+ | 0.00355(3) | |||
| 79Kr | 36 | 43 | 78.920082(4) | 35.04(10) h | β+ | 79Br | 1/2- | ||
| 79mKr | 129.77(5) keV | 50(3) s | 7/2+ | ||||||
| 80Kr | 36 | 44 | 79.9163790(16) | Stable | 0+ | 0.02286(10) | |||
| 81KrUsed to date groundwater Groundwater Groundwater is water located beneath the ground surface in soil pore spaces and in the fractures of rock formations. A unit of rock or an unconsolidated deposit is called an aquifer when it can yield a usable quantity of water. The depth at which soil pore spaces or fractures and voids in rock... |
36 | 45 | 80.9165920(21) | 2.29(11)×105 a | EC Electron capture Electron capture is a process in which a proton-rich nuclide absorbs an inner atomic electron and simultaneously emits a neutrino... |
81Br | 7/2+ | ||
| 81mKr | 190.62(4) keV | 13.10(3) s | 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.... (99.975%) |
81Kr | 1/2- | ||||
| EC (.025%) | 81Br | ||||||||
| 82Kr | 36 | 46 | 81.9134836(19) | Stable | 0+ | 0.11593(31) | |||
| 83KrFission product Fission product Nuclear fission products are the atomic fragments left after a large atomic nucleus fissions. Typically, a large nucleus like that of uranium fissions by splitting into two smaller nuclei, along with a few neutrons and a large release of energy in the form of heat , gamma rays and neutrinos. The... |
36 | 47 | 82.914136(3) | Stable | 9/2+ | 0.11500(19) | |||
| 83m1Kr | 9.4053(8) keV | 154.4(11) ns | 7/2+ | ||||||
| 83m2Kr | 41.5569(10) keV | 1.83(2) h | IT | 83Kr | 1/2- | ||||
| 84Kr | 36 | 48 | 83.911507(3) | Stable | 0+ | 0.56987(15) | |||
| 84mKr | 3236.02(18) keV | 1.89(4) µs | 8+ | ||||||
| 85Kr Krypton-85 Krypton 85 is a radioisotope of krypton.It decays into rubidium-85, with a half-life of 10.756 years and a maximum decay energy of 0.687 MeV.Its most common decay is by beta particle emission with maximum energy of 687... |
36 | 49 | 84.9125273(21) | 10.776(3) a | β- | 85Rb | 9/2+ | ||
| 85m1Kr | 304.871(20) keV | 4.480(8) h | β- (78.6%) | 85Rb | 1/2- | ||||
| IT (21.4%) | 85Kr | ||||||||
| 85m2Kr | 1991.8(13) keV | 1.6(7) µs [1.2(+10-4) µs] |
(17/2+) | ||||||
| 86Kr | 36 | 50 | 85.91061073(11) | Observationally StableBelieved to decay by β-β- to 86Sr | 0+ | 0.17279(41) | |||
| 87Kr | 36 | 51 | 86.91335486(29) | 76.3(5) min | β- | 87Rb | 5/2+ | ||
| 88Kr | 36 | 52 | 87.914447(14) | 2.84(3) h | β- | 88Rb | 0+ | ||
| 89Kr | 36 | 53 | 88.91763(6) | 3.15(4) min | β- | 89Rb | 3/2(+#) | ||
| 90Kr | 36 | 54 | 89.919517(20) | 32.32(9) s | β- | 90mRb | 0+ | ||
| 91Kr | 36 | 55 | 90.92345(6) | 8.57(4) s | β- | 91Rb | 5/2(+) | ||
| 92Kr | 36 | 56 | 91.926156(13) | 1.840(8) s | β- (99.96%) | 92Rb | 0+ | ||
| β-, n Neutron emission Neutron emission is a type of radioactive decay of atoms containing excess neutrons, in which a neutron is simply ejected from the nucleus. Two examples of isotopes which emit neutrons are helium-5 and beryllium-13... (.033%) |
91Rb | ||||||||
| 93Kr | 36 | 57 | 92.93127(11) | 1.286(10) s | β- (98.05%) | 93Rb | 1/2+ | ||
| β-, n (1.95%) | 92Rb | ||||||||
| 94Kr | 36 | 58 | 93.93436(32)# | 210(4) ms | β- (94.3%) | 94Rb | 0+ | ||
| β-, n (5.7%) | 93Rb | ||||||||
| 95Kr | 36 | 59 | 94.93984(43)# | 114(3) ms | β- | 95Rb | 1/2(+) | ||
| 96Kr | 36 | 60 | 95.94307(54)# | 80(7) ms | β- | 96Rb | 0+ | ||
| 97Kr | 36 | 61 | 96.94856(54)# | 63(4) ms | β- | 97Rb | 3/2+# | ||
| β-, n | 96Rb | ||||||||
| 98Kr | 36 | 62 | 97.95191(64)# | 46(8) ms | 0+ | ||||
| 99Kr | 36 | 63 | 98.95760(64)# | 40(11) ms | (3/2+)# | ||||
| 100Kr | 36 | 64 | 99.96114(54)# | 10# ms [>300 ns] |
0+ | ||||
| 101Kr New isotope. | 36 | 65 | unknown | >635 ns | β- 2n , β- n, β- | (in order of decay mode) 99Rb, 100Rb, 101Rb | unknown | syn | syn |