Isotopes of beryllium

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Isotopes of beryllium  (4Be)
Main isotopes [1] Decay
abun­dance half-life (t1/2) mode pro­duct
7Be trace 53.22 d ε 7Li
8Be synth 81.9 as α 4He
9Be100% stable
10Be trace1.387×106 y β− 10B
Standard atomic weight Ar°(Be)

Beryllium (4Be) has 11 known isotopes and 3 known isomers, but only one of these isotopes (9
Be
) is stable and a primordial nuclide. As such, beryllium is considered a monoisotopic element. It is also a mononuclidic element, because its other isotopes have such short half-lives that none are primordial and their abundance is very low (standard atomic weight is 9.0121831(5)). Beryllium is unique as being the only monoisotopic element with both an even number of protons and an odd number of neutrons. There are 25 other monoisotopic elements but all have odd atomic numbers, and even numbers of neutrons.

Contents

Of the 10 radioisotopes of beryllium, the most stable are 10
Be
 with a half-life of 1.387(12) million years [nb 1] and 7
Be
 with a half-life of 53.22(6) d. All other radioisotopes have half-lives under 15 s, most under 30 milliseconds. The least stable isotope is 16
Be
, with a half-life of 650(130) yoctoseconds.

The 1:1 neutron–proton ratio seen in stable isotopes of many light elements (up to oxygen, and in elements with even atomic number up to calcium) is prevented in beryllium by the extreme instability of 8
Be
 toward alpha decay, which is favored due to the extremely tight binding of 4
He
 nuclei. The half-life for the decay of 8
Be
 is only 81.9(3.7) attoseconds.

Beryllium is prevented from having a stable isotope with 4 protons and 6 neutrons by the very lopsided neutron–proton ratio for such a light element. Nevertheless, this isotope, 10
Be
, has a half-life of 1.387(12) million years, [nb 1] which indicates unusual stability for a light isotope with such a large neutron/proton imbalance. Other possible beryllium isotopes have even more severe mismatches in neutron and proton number, and thus are even less stable.

Most 9
Be
 in the universe is thought to be formed by cosmic ray nucleosynthesis from cosmic ray spallation in the period between the Big Bang and the formation of the Solar System. The isotopes 7
Be
, with a half-life of 53.22(6) d, and 10
Be
 are both cosmogenic nuclides because they are made on a recent timescale in the Solar System by spallation, [4] like 14
C
.

List of isotopes

Nuclide
[n 1] 		Z N Isotopic mass (Da) [5]
[n 2] [n 3] 		Half-life [1]

[resonance width]		 Decay
mode [1]
[n 4] 		Daughter
isotope
[n 5] 		Spin and
parity [1]
[n 6] 		Isotopic
abundance
Excitation energy
5
Be
 [n 7] 		415.03987(215)# p  ? [n 8] 4
Li
 ?		(1/2+)#
6
Be
426.019726(6)5.0(3) zs
[91.6(5.6) keV]		 2p 4
He
0+
7
Be
 [n 9] 		437.01692871(8)53.22(6) d ε 7
Li
3/2−Trace [n 10]
8
Be
 [n 11] 		448.00530510(4)81.9(3.7) as
[5.58(25) eV]		α [n 12] 4
He
0+
8m
Be
16626(3) keVα4
He
2+
9
Be
459.01218306(8)Stable3/2−1
9m
Be
14390.3(1.7) keV1.25(10) as
[367(30) eV]		3/2−
10
Be
 		4610.01353469(9)1.387(12)×106 y [nb 1] β− 10
B
0+Trace [n 10]
11
Be
 [n 13] 		4711.02166108(26)13.76(7) sβ− (96.7(1)%)11
B
1/2+
β−α (3.3(1)%)7
Li
β−p (0.0013(3)%)10
Be
11m
Be
21158(20) keV0.93(13) zs
[500(75) keV]		 IT  ? [n 8] 11
Be
 ?		3/2−
12
Be
4812.0269221(20)21.46(5) msβ− (99.50(3)%)12
B
0+
β−n (0.50(3)%)11
B
12m
Be
2251(1) keV233(7) ns IT 12
Be
0+
13
Be
4913.036135(11)1.0(7) zs n  ? [n 8] 12
Be
 ?		(1/2−)
13m
Be
1500(50) keV(5/2+)
14
Be
 [n 14] 		41014.04289(14)4.53(27) msβ−n (86(6)%)13
B
0+
β− (> 9.0(6.3)%)14
B
β−2n (5(2)%)12
B
β−t (0.02(1)%)11
Be
β−α (< 0.004%)10
Li
14m
Be
1520(150) keV(2+)
15
Be
41115.05349(18)790(270) ysn14
Be
(5/2+)
16
Be
41216.06167(18)650(130) ys
[0.73(18) MeV]		2n14
Be
0+
This table header & footer:
  1. ↑ mBe – 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. ↑ Modes of decay:
    EC: Electron capture
    IT: Isomeric transition
    n: Neutron emission
    p: Proton emission
  5. ↑ Bold symbol as daughter – Daughter product is stable.
  6. ↑ ( ) spin value – Indicates spin with weak assignment arguments.
  7. ↑ This isotope has not yet been observed; given data is inferred or estimated from periodic trends.
  8. 1 2 3 Decay mode shown is energetically allowed, but has not been experimentally observed to occur in this nuclide.
  9. ↑ Produced in Big Bang nucleosynthesis, but not primordial, as it all quickly decayed to 7Li
  10. 1 2 cosmogenic nuclide
  11. ↑ Intermediate product of triple alpha process in stellar nucleosynthesis as part of the path producing 12C
  12. ↑ Also often considered spontaneous fission, as 8
    Be
     splits into two equal 4
    He
     nuclei
  13. ↑ Has 1 halo neutron
  14. ↑ Has 4 halo neutrons

Beryllium-7

Beryllium-7 is an isotope with a half-life of 53.3 days that is generated naturally as a cosmogenic nuclide. [4] The rate at which the short-lived 7
Be
 is transferred from the air to the ground is controlled in part by the weather. 7
Be
 decay in the Sun is one of the sources of solar neutrinos, and the first type ever detected using the Homestake experiment. Presence of 7
Be
 in sediments is often used to establish that they are fresh, i.e. less than about 3–4 months in age, or about two half-lives of 7
Be
. [6]

The rate of delivery of Be from the air to the ground in Japan Be7fromcosmicrays.png
The rate of delivery of
Be
 from the air to the ground in Japan

Beryllium-10

Plot showing variations in solar activity, including variation in Be concentration which varies inversely with solar activity. (Note that the beryllium scale is inverted, so increases on this scale indicate lower beryllium-10 levels). Solar Activity Proxies.png
Plot showing variations in solar activity, including variation in Be concentration which varies inversely with solar activity. (Note that the beryllium scale is inverted, so increases on this scale indicate lower beryllium-10 levels).

Beryllium-10 has a half-life of 1.39×106 y, and decays by beta decay to stable boron-10 with a maximum energy of 556.2 keV. [7] [8] It is formed in the Earth's atmosphere mainly by cosmic ray spallation of nitrogen and oxygen. [9] [10] [11] 10Be and its daughter product have been used to examine soil erosion, soil formation from regolith, the development of lateritic soils and the age of ice cores. [12] 10Be is a significant isotope used as a proxy data measure for cosmogenic nuclides to characterize solar and extra-solar attributes of the past from terrestrial samples. [13]

Decay chains

Most isotopes of beryllium within the proton/neutron drip lines decay via beta decay and/or a combination of beta decay and alpha decay or neutron emission. However, 7
Be
 decays only via electron capture, a phenomenon to which its unusually long half-life may be attributed. Notably, its half-life can be artificially lowered by 0.83% via endohedral enclosure (7Be@C60). [14] Also anomalous is 8
Be
, which decays via alpha decay to 4
He
. This alpha decay is often considered fission, which would be able to account for its extremely short half-life.

Notes

  1. 1 2 3 Note that NUBASE2020 uses the tropical year to convert between years and other units of time, not the Gregorian year. The relationship between years and other time units in NUBASE2020 is as follows: 1 y = 365.2422 d = 31 556 926 s

Related Research Articles

<span class="mw-page-title-main">Stable nuclide</span> Nuclide that does not undergo radioactive decay

Stable nuclides are isotopes of a chemical element whose nucleons are in a configuration that does not permit them the surplus energy required to produce a radioactive emission. The nuclei of such isotopes are not radioactive and unlike radionuclides do not spontaneously undergo radioactive decay. When these nuclides are referred to in relation to specific elements they are usually called that element's stable isotopes.

<span class="mw-page-title-main">Nucleosynthesis</span> Process that creates new atomic nuclei from pre-existing nucleons, primarily protons and neutrons

Nucleosynthesis is the process that creates new atomic nuclei from pre-existing nucleons and nuclei. According to current theories, the first nuclei were formed a few minutes after the Big Bang, through nuclear reactions in a process called Big Bang nucleosynthesis. After about 20 minutes, the universe had expanded and cooled to a point at which these high-energy collisions among nucleons ended, so only the fastest and simplest reactions occurred, leaving our universe containing hydrogen and helium. The rest is traces of other elements such as lithium and the hydrogen isotope deuterium. Nucleosynthesis in stars and their explosions later produced the variety of elements and isotopes that we have today, in a process called cosmic chemical evolution. The amounts of total mass in elements heavier than hydrogen and helium remains small, so that the universe still has approximately the same composition.

<span class="mw-page-title-main">Electron capture</span> Process in which a proton-rich nuclide absorbs an inner atomic electron

Electron capture is a process in which the proton-rich nucleus of an electrically neutral atom absorbs an inner atomic electron, usually from the K or L electron shells. This process thereby changes a nuclear proton to a neutron and simultaneously causes the emission of an electron neutrino.

<span class="mw-page-title-main">Nuclide</span> Atomic species

A nuclide is a class of atoms characterized by their number of protons, Z, their number of neutrons, N, and their nuclear energy state.

<span class="mw-page-title-main">Beryllium-10</span> Isotope of beryllium

Beryllium-10 (10Be) is a radioactive isotope of beryllium. It is formed in the Earth's atmosphere mainly by cosmic ray spallation of nitrogen and oxygen. Beryllium-10 has a half-life of 1.39 × 106 years, and decays by beta decay to stable boron-10 with a maximum energy of 556.2 keV. It decays through the reaction 10Be→10B + e−. Light elements in the atmosphere react with high energy galactic cosmic ray particles. The spallation of the reaction products is the source of 10Be (t, u particles like n or p):

<span class="mw-page-title-main">Isotopes of hydrogen</span>

Hydrogen (1H) has three naturally occurring isotopes: 1H, 2H, and 3H. 1H and 2H are stable, while 3H has a half-life of 12.32(2) years. Heavier isotopes also exist; all are synthetic and have a half-life of less than 1 zeptosecond (10−21 s). Of these, 5H is the least stable, while 7H is the most.

Cosmic ray spallation, also known as the x-process, is a set of naturally occurring nuclear reactions causing nucleosynthesis; it refers to the formation of chemical elements from the impact of cosmic rays on an object. Cosmic rays are highly energetic charged particles from beyond Earth, ranging from protons, alpha particles, and nuclei of many heavier elements. About 1% of cosmic rays also consist of free electrons.

Naturally occurring lithium (3Li) is composed of two stable isotopes, lithium-6 (6Li) and lithium-7 (7Li), with the latter being far more abundant on Earth. Both of the natural isotopes have an unexpectedly low nuclear binding energy per nucleon when compared with the adjacent lighter and heavier elements, helium and beryllium. The longest-lived radioisotope of lithium is 8Li, which has a half-life of just 838.7(3) milliseconds. 9Li has a half-life of 178.2(4) ms, and 11Li has a half-life of 8.75(6) ms. All of the remaining isotopes of lithium have half-lives that are shorter than 10 nanoseconds. The shortest-lived known isotope of lithium is 4Li, which decays by proton emission with a half-life of about 91(9) yoctoseconds, although the half-life of 3Li is yet to be determined, and is likely to be much shorter, like 2He which undergoes proton emission within 10−9 s.

Naturally occurring nickel (28Ni) is composed of five stable isotopes; 58
Ni
, 60
Ni
, 61
Ni
, 62
Ni
 and 64
Ni
, with 58
Ni
 being the most abundant. 26 radioisotopes have been characterised with the most stable being 59
Ni
 with a half-life of 76,000 years, 63
Ni
 with a half-life of 100.1 years, and 56
Ni
 with a half-life of 6.077 days. All of the remaining radioactive isotopes have half-lives that are less than 60 hours and the majority of these have half-lives that are less than 30 seconds. This element also has 8 meta states.

Calcium (20Ca) has 26 known isotopes, ranging from 35Ca to 60Ca. There are five stable isotopes, plus one isotope (48Ca) with such a long half-life that it is for all practical purposes stable. The most abundant isotope, 40Ca, as well as the rare 46Ca, are theoretically unstable on energetic grounds, but their decay has not been observed. Calcium also has a cosmogenic isotope, 41Ca, with half-life 99,400 years. Unlike cosmogenic isotopes that are produced in the air, 41Ca is produced by neutron activation of 40Ca. Most of its production is in the upper metre of the soil column, where the cosmogenic neutron flux is still strong enough. 41Ca has received much attention in stellar studies because it decays to 41K, a critical indicator of solar system anomalies. The most stable artificial isotopes are 45Ca with half-life 163 days and 47Ca with half-life 4.5 days. All other calcium isotopes have half-lives of minutes or less.

Chlorine (17Cl) has 25 isotopes, ranging from 28Cl to 52Cl, and two isomers, 34mCl and 38mCl. There are two stable isotopes, 35Cl (75.8%) and 37Cl (24.2%), giving chlorine a standard atomic weight of 35.45. The longest-lived radioactive isotope is 36Cl, which has a half-life of 301,000 years. All other isotopes have half-lives under 1 hour, many less than one second. The shortest-lived are proton-unbound 29Cl and 30Cl, with half-lives less than 10 picoseconds and 30 nanoseconds, respectively; the half-life of 28Cl is unknown.

Aluminium or aluminum (13Al) has 23 known isotopes from 21Al to 43Al and 4 known isomers. Only 27Al (stable isotope) and 26Al (radioactive isotope, t1/2 = 7.2×105 y) occur naturally, however 27Al comprises nearly all natural aluminium. Other than 26Al, all radioisotopes have half-lives under 7 minutes, most under a second. The standard atomic weight is 26.9815385(7). 26Al is produced from argon in the atmosphere by spallation caused by cosmic-ray protons. Aluminium isotopes have found practical application in dating marine sediments, manganese nodules, glacial ice, quartz in rock exposures, and meteorites. The ratio of 26Al to 10Be has been used to study the role of sediment transport, deposition, and storage, as well as burial times, and erosion, on 105 to 106 year time scales. 26Al has also played a significant role in the study of meteorites.

Carbon (6C) has 14 known isotopes, from 8
C
 to 20
C
 as well as 22
C
, of which 12
C
 and 13
C
 are stable. The longest-lived radioisotope is 14
C
, with a half-life of 5.70(3)×103 years. This is also the only carbon radioisotope found in nature, as trace quantities are formed cosmogenically by the reaction 14
N
 +
n
 → 14
C
 + 1
H
. The most stable artificial radioisotope is 11
C
, which has a half-life of 20.3402(53) min. All other radioisotopes have half-lives under 20 seconds, most less than 200 milliseconds. The least stable isotope is 8
C
, with a half-life of 3.5(1.4)×10−21 s. Light isotopes tend to decay into isotopes of boron and heavy ones tend to decay into isotopes of nitrogen.

<span class="mw-page-title-main">Isotopes of boron</span>

Boron (5B) naturally occurs as isotopes 10
B
 and 11
B
, the latter of which makes up about 80% of natural boron. There are 13 radioisotopes that have been discovered, with mass numbers from 7 to 21, all with short half-lives, the longest being that of 8
B
, with a half-life of only 771.9(9) ms and 12
B
 with a half-life of 20.20(2) ms. All other isotopes have half-lives shorter than 17.35 ms. Those isotopes with mass below 10 decay into helium while those with mass above 11 mostly become carbon.

Cosmogenic nuclides are rare nuclides (isotopes) created when a high-energy cosmic ray interacts with the nucleus of an in situ Solar System atom, causing nucleons to be expelled from the atom. These nuclides are produced within Earth materials such as rocks or soil, in Earth's atmosphere, and in extraterrestrial items such as meteoroids. By measuring cosmogenic nuclides, scientists are able to gain insight into a range of geological and astronomical processes. There are both radioactive and stable cosmogenic nuclides. Some of these radionuclides are tritium, carbon-14 and phosphorus-32.

<span class="mw-page-title-main">Valley of stability</span> Characterization of nuclide stability

In nuclear physics, the valley of stability is a characterization of the stability of nuclides to radioactivity based on their binding energy. Nuclides are composed of protons and neutrons. The shape of the valley refers to the profile of binding energy as a function of the numbers of neutrons and protons, with the lowest part of the valley corresponding to the region of most stable nuclei. The line of stable nuclides down the center of the valley of stability is known as the line of beta stability. The sides of the valley correspond to increasing instability to beta decay. The decay of a nuclide becomes more energetically favorable the further it is from the line of beta stability. The boundaries of the valley correspond to the nuclear drip lines, where nuclides become so unstable they emit single protons or single neutrons. Regions of instability within the valley at high atomic number also include radioactive decay by alpha radiation or spontaneous fission. The shape of the valley is roughly an elongated paraboloid corresponding to the nuclide binding energies as a function of neutron and atomic numbers.

<span class="mw-page-title-main">Neutron number</span> The number of neutrons in a nuclide

The neutron number is the number of neutrons in a nuclide.

<span class="mw-page-title-main">Isotope</span> Different atoms of the same element

Isotopes are distinct nuclear species of the same chemical element. They have the same atomic number and position in the periodic table, but different nucleon numbers due to different numbers of neutrons in their nuclei. While all isotopes of a given element have similar chemical properties, they have different atomic masses and physical properties.

Surface exposure dating is a collection of geochronological techniques for estimating the length of time that a rock has been exposed at or near Earth's surface. Surface exposure dating is used to date glacial advances and retreats, erosion history, lava flows, meteorite impacts, rock slides, fault scarps, cave development, and other geological events. It is most useful for rocks which have been exposed for between 103 and 106 years.

<span class="mw-page-title-main">Even and odd atomic nuclei</span> Nuclear physics classification method

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References

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  2. ↑ "Standard Atomic Weights: Beryllium". CIAAW. 2013.
  3. ↑ Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; Böhlke, John K.; Chesson, Lesley A.; Coplen, Tyler B.; Ding, Tiping; Dunn, Philip J. H.; Gröning, Manfred; Holden, Norman E.; Meijer, Harro A. J. (2022-05-04). "Standard atomic weights of the elements 2021 (IUPAC Technical Report)". Pure and Applied Chemistry. doi:10.1515/pac-2019-0603. ISSN   1365-3075.
  4. 1 2 Mishra, Ritesh Kumar; Marhas, Kuljeet Kaur (2019-03-25). "Meteoritic evidence of a late superflare as source of 7 Be in the early Solar System". Nature Astronomy. 3 (6): 498–505. Bibcode:2019NatAs...3..498M. doi:10.1038/s41550-019-0716-0. ISSN   2397-3366. S2CID   126552874.
  5. ↑ 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.
  6. 1 2 Yamamoto, Masayoshi; Sakaguchi, Aya; Sasaki, Keiichi; Hirose, Katsumi; Igarashi, Yasuhito; Kim, Chang Kyu (January 2006). "Seasonal and spatial variation of atmospheric 210Pb and 7Be deposition: features of the Japan Sea side of Japan". Journal of Environmental Radioactivity. 86 (1): 110–131. doi:10.1016/j.jenvrad.2005.08.001. PMID   16181712.
  7. ↑ G. Korschinek; A. Bergmaier; T. Faestermann; U. C. Gerstmann (2010). "A new value for the half-life of 10Be by Heavy-Ion Elastic Recoil Detection and liquid scintillation counting". Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms. 268 (2): 187–191. Bibcode:2010NIMPB.268..187K. doi:10.1016/j.nimb.2009.09.020.
  8. ↑ J. Chmeleff; F. von Blanckenburg; K. Kossert; D. Jakob (2010). "Determination of the 10Be half-life by multicollector ICP-MS and liquid scintillation counting". Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms. 268 (2): 192–199. Bibcode:2010NIMPB.268..192C. doi:10.1016/j.nimb.2009.09.012.
  9. ↑ G.A. Kovaltsov; I.G. Usoskin (2010). "A new 3D numerical model of cosmogenic nuclide 10Be production in the atmosphere". Earth Planet. Sci. Lett. 291 (1–4): 182–199. Bibcode:2010E&PSL.291..182K. doi:10.1016/j.epsl.2010.01.011.
  10. ↑ J. Beer; K. McCracken; R. von Steiger (2012). Cosmogenic radionuclides: theory and applications in the terrestrial and space environments. Physics of Earth and Space Environments. Vol. 26. Physics of Earth and Space Environments, Springer, Berlin. doi:10.1007/978-3-642-14651-0. ISBN   978-3-642-14650-3. S2CID   55739885.
  11. ↑ S.V. Poluianov; G.A. Kovaltsov; A.L. Mishev; I.G. Usoskin (2016). "Production of cosmogenic isotopes 7Be, 10Be, 14C, 22Na, and 36Cl in the atmosphere: Altitudinal profiles of yield functions". J. Geophys. Res. Atmos. 121 (13): 8125–8136. arXiv: 1606.05899 . Bibcode:2016JGRD..121.8125P. doi:10.1002/2016JD025034. S2CID   119301845.
  12. ↑ Balco, Greg; Shuster, David L. (2009). "26Al-10Be–21Ne burial dating" (PDF). Earth and Planetary Science Letters . 286 (3–4): 570–575. Bibcode:2009E&PSL.286..570B. doi:10.1016/j.epsl.2009.07.025. Archived from the original (PDF) on 2015-09-23. Retrieved 2012-12-10.
  13. ↑ Paleari, Chiara I.; F. Mekhaldi; F. Adolphi; M. Christl; C. Vockenhuber; P. Gautschi; J. Beer; N. Brehm; T. Erhardt; H.-A. Synal; L. Wacker; F. Wilhelms; R. Muscheler (2022). "Cosmogenic radionuclides reveal an extreme solar particle storm near a solar minimum 9125 years BP". Nat. Commun. 13 (214): 214. Bibcode:2022NatCo..13..214P. doi: 10.1038/s41467-021-27891-4 . PMC   8752676 . PMID   35017519.
  14. ↑ Ohtsuki, T.; Yuki, H.; Muto, M.; Kasagi, J.; Ohno, K. (9 September 2004). "Enhanced Electron-Capture Decay Rate of 7Be Encapsulated in C60 Cages". Physical Review Letters. 93 (11): 112501. Bibcode:2004PhRvL..93k2501O. doi:10.1103/PhysRevLett.93.112501. PMID   15447332 . Retrieved 23 February 2022.
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