Although
berylliumBeryllium is the chemical element with the symbol Be and atomic number 4. It is a divalent element which occurs naturally only in combination with other elements in minerals. Notable gemstones which contain beryllium include beryl and chrysoberyl...
(
Be) has 12 known
isotopeIsotopes 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, only one of these isotopes is stable and a
primordial nuclideIn geochemistry and geonuclear physics, primordial nuclides or primordial isotopes are nuclides found on the earth that have existed in their current form since before Earth was formed. Only 288 such nuclides are known...
. As such, it is considered a
monoisotopic elementA monoisotopic element is one of 26 chemical elements which have only a single stable isotope . A list is given in a following section....
. It is also a mononuclidic element, because its other isotopes are short-lived that none are primordial and their abundance is very low. Most in the universe is thought to be formed by cosmic ray nucleosynthesis from
cosmic ray spallationCosmic ray spallation is a form of naturally occurring nuclear fission and nucleosynthesis. It refers to the formation of elements from the impact of cosmic rays on an object. Cosmic rays are highly energetic charged particles from outside of Earth ranging from protons, alpha particles, and nuclei...
in the period between the
Big BangThe Big Bang theory is the prevailing cosmological model that explains the early development of the Universe. According to the Big Bang theory, the Universe was once in an extremely hot and dense state which expanded rapidly. This rapid expansion caused the young Universe to cool and resulted in...
and the formation of the solar system.
Of the 11 radioisotopes of beryllium, the most stable are
10Be with a half-life of 1.39 million years and
7Be with a half-life of 53.22 days. All other radioisotopes have half-lives under 13.85 seconds, most under 20 milliseconds. The least stable isotope is
6Be, with a half-life measured as 92 keV.
Beryllium is unique as being the only monoisotopic element with an even number of protons. It is also the only one with an odd number of neutrons. There are 20 other monoisotopic elements (fluorine, sodium, aluminum, phosphorus, scandium, manganese, cobalt, arsenic, yttrium, niobium, rhodium, iodine, cesium, praseodymium, terbium, holmium, thulium, gold, bismuth, and thorium) but all have odd atomic numbers (except thorium), and even numbers of neutrons.
The natural light-element ratio of equal protons and neutron numbers is prevented in beryllium by the extreme instability of toward double-
alpha decayAlpha 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...
, which is favored due to the extremely tight binding of
Although
berylliumBeryllium is the chemical element with the symbol Be and atomic number 4. It is a divalent element which occurs naturally only in combination with other elements in minerals. Notable gemstones which contain beryllium include beryl and chrysoberyl...
(
Be) has 12 known
isotopeIsotopes 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, only one of these isotopes ({{SimpleNuclide|Beryllium|9}}) is stable and a
primordial nuclideIn geochemistry and geonuclear physics, primordial nuclides or primordial isotopes are nuclides found on the earth that have existed in their current form since before Earth was formed. Only 288 such nuclides are known...
. As such, it is considered a
monoisotopic elementA monoisotopic element is one of 26 chemical elements which have only a single stable isotope . A list is given in a following section....
. It is also a mononuclidic element, because its other isotopes are short-lived that none are primordial and their abundance is very low. Most {{SimpleNuclide|Beryllium|9}} in the universe is thought to be formed by cosmic ray nucleosynthesis from
cosmic ray spallationCosmic ray spallation is a form of naturally occurring nuclear fission and nucleosynthesis. It refers to the formation of elements from the impact of cosmic rays on an object. Cosmic rays are highly energetic charged particles from outside of Earth ranging from protons, alpha particles, and nuclei...
in the period between the
Big BangThe Big Bang theory is the prevailing cosmological model that explains the early development of the Universe. According to the Big Bang theory, the Universe was once in an extremely hot and dense state which expanded rapidly. This rapid expansion caused the young Universe to cool and resulted in...
and the formation of the solar system.
Of the 11 radioisotopes of beryllium, the most stable are
10Be with a half-life of 1.39 million years and
7Be with a half-life of 53.22 days. All other radioisotopes have half-lives under 13.85 seconds, most under 20 milliseconds. The least stable isotope is
6Be, with a half-life measured as 92 keV.
Beryllium is unique as being the only monoisotopic element with an even number of protons. It is also the only one with an odd number of neutrons. There are 20 other monoisotopic elements (fluorine, sodium, aluminum, phosphorus, scandium, manganese, cobalt, arsenic, yttrium, niobium, rhodium, iodine, cesium, praseodymium, terbium, holmium, thulium, gold, bismuth, and thorium) but all have odd atomic numbers (except thorium), and even numbers of neutrons.
The natural light-element ratio of equal protons and neutron numbers is prevented in beryllium by the extreme instability of {{SimpleNuclide|Beryllium|8}} toward double-
alpha decayAlpha 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...
, which is favored due to the extremely tight binding of
Although
berylliumBeryllium is the chemical element with the symbol Be and atomic number 4. It is a divalent element which occurs naturally only in combination with other elements in minerals. Notable gemstones which contain beryllium include beryl and chrysoberyl...
(
Be) has 12 known
isotopeIsotopes 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, only one of these isotopes ({{SimpleNuclide|Beryllium|9}}) is stable and a
primordial nuclideIn geochemistry and geonuclear physics, primordial nuclides or primordial isotopes are nuclides found on the earth that have existed in their current form since before Earth was formed. Only 288 such nuclides are known...
. As such, it is considered a
monoisotopic elementA monoisotopic element is one of 26 chemical elements which have only a single stable isotope . A list is given in a following section....
. It is also a mononuclidic element, because its other isotopes are short-lived that none are primordial and their abundance is very low. Most {{SimpleNuclide|Beryllium|9}} in the universe is thought to be formed by cosmic ray nucleosynthesis from
cosmic ray spallationCosmic ray spallation is a form of naturally occurring nuclear fission and nucleosynthesis. It refers to the formation of elements from the impact of cosmic rays on an object. Cosmic rays are highly energetic charged particles from outside of Earth ranging from protons, alpha particles, and nuclei...
in the period between the
Big BangThe Big Bang theory is the prevailing cosmological model that explains the early development of the Universe. According to the Big Bang theory, the Universe was once in an extremely hot and dense state which expanded rapidly. This rapid expansion caused the young Universe to cool and resulted in...
and the formation of the solar system.
Of the 11 radioisotopes of beryllium, the most stable are
10Be with a half-life of 1.39 million years and
7Be with a half-life of 53.22 days. All other radioisotopes have half-lives under 13.85 seconds, most under 20 milliseconds. The least stable isotope is
6Be, with a half-life measured as 92 keV.
Beryllium is unique as being the only monoisotopic element with an even number of protons. It is also the only one with an odd number of neutrons. There are 20 other monoisotopic elements (fluorine, sodium, aluminum, phosphorus, scandium, manganese, cobalt, arsenic, yttrium, niobium, rhodium, iodine, cesium, praseodymium, terbium, holmium, thulium, gold, bismuth, and thorium) but all have odd atomic numbers (except thorium), and even numbers of neutrons.
The natural light-element ratio of equal protons and neutron numbers is prevented in beryllium by the extreme instability of {{SimpleNuclide|Beryllium|8}} toward double-
alpha decayAlpha 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...
, which is favored due to the extremely tight binding of {{SimpleNuclide nuclei. The half-life for the decay of {{SimpleNuclide|Beryllium|8}} is only 6.7(17)×10
−17 seconds.
Beryllium is prevented from having a stable isotope with 4 protons and 6 neutrons by the very large mismatch in proton/neutron ratio for such a light element. Nevertheless, this isotope,
{{SimpleNuclideBeryllium-10 is a radioactive isotope of beryllium. It is formed mainly by cosmic ray spallation. Be-10 has a half-life of 1.36 × 106 years, and decays by beta decay to stable Boron-10 with a maximum energy of 556.2 keV....
, has a half-life of 1.39 million years, which indicates unusual stability for a light isotope with such a large neutron/proton imbalance.
Still other possible beryllium isotopes have even more severe mismatches in neutron and proton number, and thus are even less stable.
The isotopes {{SimpleNuclide|Beryllium|7}}, with a half-life of 53 days, and {{SimpleNuclide|Beryllium|10}} are both cosmogenic nuclides because they are made on a recent timescale in the solar system by
cosmic ray spallationCosmic ray spallation is a form of naturally occurring nuclear fission and nucleosynthesis. It refers to the formation of elements from the impact of cosmic rays on an object. Cosmic rays are highly energetic charged particles from outside of Earth ranging from protons, alpha particles, and nuclei...
s, like
{{SimpleNuclideCarbon-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...
. These two radioisotopes of beryllium in the atmosphere track the
sun spotSun SPOT is a wireless sensor network mote developed by Sun Microsystems. The device is built upon the IEEE 802.15.4 standard...
cycle and solar activity, since this affects the magnetic field that shields the Earth from cosmic rays. The rate at which the short-lived {{SimpleNuclide|Beryllium|7}} is transferred from the air to the ground is controlled in part by the weather.
{{SimpleNuclide|Beryllium|7}} decay in the sun is one of the sources of
solar neutrinoElectron neutrinos are produced in the Sun as a product of nuclear fusion. By far the largest fraction of neutrinos passing through the Earth are Solar neutrinos....
s, and the first type ever detected using the
Homestake experimentThe Homestake experiment was an experiment headed by astrophysicists Raymond Davis, Jr. and John N. Bahcall in the late 1960s. Its purpose was to collect and count neutrinos emitted by nuclear fusion taking place in the Sun. Bahcall did the theoretical calculations and Davis designed the experiment...
.
Beryllium has a standard atomic mass of: 9.012182(3) u
Table
nuclide
symbol |
Z(pThe 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(nThe 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 captureElectron capture is a process in which a proton-rich nuclide absorbs an inner atomic electron and simultaneously emits a neutrino...
|
daughter
isotope(s)[Bold for stable isotopes] |
nuclear
spin |
representative
isotopic
composition
(mole fraction) |
range of natural
variation
(mole fraction) |
| {{SimpleNuclide|Beryllium|5}} |
4 |
1 |
5.04079(429)# |
|
p 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...
|
{{SimpleNuclide|Lithium|4}} |
(1/2+)# |
|
|
| {{SimpleNuclide|Beryllium|6}} |
4 |
2 |
6.019726(6) |
5.0(3)×10−21 s
[0.092(6) MeV] |
2p |
{{SimpleNuclide|Helium|4}} |
0+ |
|
|
{{SimpleNuclide|Beryllium|7}}[Produced in Big Bang nucleosynthesis]In physical cosmology, Big Bang nucleosynthesis refers to the production of nuclei other than those of H-1 during the early phases of the universe...
, but not primordial, as it all quickly decayed to 7Li |
4 |
3 |
7.01692983(11) |
53.22(6) d |
ECElectron capture is a process in which a proton-rich nuclide absorbs an inner atomic electron and simultaneously emits a neutrino...
|
{{SimpleNuclide|Lithium|7}} |
3/2- |
Trace[cosmogenic nuclide] |
|
{{SimpleNuclide|Beryllium|8}}[Intermediate product of triple alpha process in stellar nucleosynthesis]Stellar nucleosynthesis is the collective term for the nuclear reactions taking place in stars to build the nuclei of the elements heavier than hydrogen. Some small quantity of these reactions also occur on the stellar surface under various circumstances...
as part of the path producing 12CCarbon-12 is the more abundant of the two stable isotopes of the element carbon, accounting for 98.89% of carbon; it contains 6 protons, 6 neutrons, and 6 electrons....
|
4 |
4 |
8.00530510(4) |
6.7(17)×10−17 s
[6.8(17) eV] |
fission |
2 {{SimpleNuclide|Helium|4}} |
0+ |
|
|
| {{SimpleNuclide|Beryllium|9}} |
4 |
5 |
9.0121822(4) |
Stable |
3/2- |
1.0000 |
|
{{SimpleNuclideBeryllium-10 is a radioactive isotope of beryllium. It is formed mainly by cosmic ray spallation. Be-10 has a half-life of 1.36 × 106 years, and decays by beta decay to stable Boron-10 with a maximum energy of 556.2 keV....
|
4 |
6 |
10.0135338(4) |
1.39×106 a |
β−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...
|
{{SimpleNuclide|Boron|10}} |
0+ |
Trace |
|
{{SimpleNuclide|Beryllium|11}}[Has 1 halo neutron] |
4 |
7 |
11.021658(7) |
13.81(8) s |
β− (97.1%) |
{{SimpleNuclide|Boron|11}} |
1/2+ |
|
|
β−, αAlpha 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...
(2.9%) |
{{SimpleNuclide|Lithium|7}} |
| {{SimpleNuclide|Beryllium|12}} |
4 |
8 |
12.026921(16) |
21.49(3) ms |
β− (99.48%) |
{{SimpleNuclide|Boron|12}} |
0+ |
|
|
| β−, n (0.52%) |
{{SimpleNuclide|Boron|11}} |
| {{SimpleNuclide|Beryllium|13}} |
4 |
9 |
13.03569(8) |
.5(1) ns |
nNeutron 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...
|
{{SimpleNuclide|Beryllium|12}} |
1/2+ |
|
|
{{SimpleNuclide|Beryllium|14}}[Has 4 halo neutrons] |
4 |
10 |
14.04289(14) |
4.84(10) ms |
β−, n (81.0%) |
{{SimpleNuclide|Boron|13}} |
0+ |
|
|
| β− (14.0%) |
{{SimpleNuclide|Boron|14}} |
| β−, 2n (5.0%) |
{{SimpleNuclide|Boron|12}} |
| {{SimpleNuclide|Beryllium|15}} |
4 |
11 |
15.05346(54)# |
<200 ns |
|
|
|
|
|
| {{SimpleNuclide|Beryllium|16}} |
4 |
12 |
16.06192(54)# |
<200 ns |
|
|
0+ |
|
|