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'''Beryllium''' is a [[chemical element]]; it has [[Symbol (chemistry)|symbol]] '''Be''' and [[atomic number]] 4. It is a steel-gray, hard, strong, lightweight and brittle [[alkaline earth metal]]. It is a [[divalent]] element that occurs naturally only in combination with other elements to form minerals. [[Gemstones]] high in beryllium include [[beryl]] ([[Aquamarine (gemstone)|aquamarine]], [[emerald]], [[red beryl]]) and [[chrysoberyl]]. It is a [[Abundance of the chemical elements#Universe|relatively rare]] element in the [[universe]], usually occurring as a product of the [[spallation]] of larger atomic nuclei that have collided with [[cosmic ray]]s. Within the cores of stars, beryllium is depleted as it is fused into heavier elements. Beryllium constitutes about 0.0004 percent by mass of Earth's crust. The world's annual beryllium production of 220 tons is usually manufactured by extraction from the mineral [[beryl]], a difficult process because beryllium bonds strongly to [[oxygen]].

In structural applications, the combination of high [[flexural rigidity]], [[Thermostability|thermal stability]], [[thermal conductivity]] and low [[density]] (1.85 times that of water) make beryllium a desirable [[aerospace]] material for aircraft components, [[missile]]s, [[spacecraft]], and [[satellites]].<ref name="deGruyter" /> Because of its low density and [[atomic mass]], beryllium is relatively transparent to [[X-ray]]s and other forms of [[ionizing radiation]]; therefore, it is the most common window material for X-ray equipment and components of [[particle detector]]s.<ref name="deGruyter" /> When added as an [[alloy]]ing element to [[aluminium]], [[copper]] (notably the alloy [[beryllium copper]]), [[iron]], or [[nickel]], beryllium improves many physical properties.<ref name="deGruyter" /> For example, tools and components made of beryllium copper [[alloy]]s are [[Strength of materials|strong]] and [[Hardness|hard]] and do not create sparks when they strike a steel surface. In air, the surface of beryllium oxidizes readily at room temperature to form a [[Passivation (chemistry)|passivation layer]] 1–10&nbsp;nm thick that protects it from further oxidation and corrosion.<ref>{{Cite journal |last1=Hoover |first1=Mark D. |last2=Castorina |first2=Bryan T. |last3=Finch |first3=Gregory L. |last4=Rothenberg |first4=Simon J. |date=October 1989 |title=Determination of the Oxide Layer Thickness on Beryllium Metal Particles |url=https://www.tandfonline.com/doi/full/10.1080/15298668991375146 |journal=American Industrial Hygiene Association Journal |language=en |volume=50 |issue=10 |pages=550–553 |doi=10.1080/15298668991375146 |pmid=2801503 |bibcode=1989AIHAJ..50..550H |issn=0002-8894}}</ref> The metal oxidizes in bulk (beyond the [[Passivation (chemistry)|passivation]] layer) when heated above {{convert|500|C}},<ref name="Tomastik2005" /> and burns brilliantly when heated to about {{convert|2500|C}}.<ref name="Maček-1969">{{cite journal |last1=Maček |first1=Andrej |last2=McKenzie Semple |first2=J. |date=1969 |title=Experimental burning rates and combustion mechanisms of single beryllium particles |url=https://linkinghub.elsevier.com/retrieve/pii/S0082078469803930 |journal=Symposium (International) on Combustion |language=en |volume=12 |issue=1 |pages=71–81 |doi=10.1016/S0082-0784(69)80393-0}}</ref>

The commercial use of beryllium requires the use of appropriate dust control equipment and industrial controls at all times because of the [[toxicity]] of inhaled beryllium-containing dusts that can cause a chronic life-threatening allergic disease, [[berylliosis]], in some people.<ref>{{cite journal |doi=10.1038/nchem.1033 |title=A brighter beryllium |date=2011 |last1=Puchta |first1=Ralph |journal=Nature Chemistry |volume=3 |issue=5 |page=416 |pmid=21505503 |bibcode=2011NatCh...3..416P |doi-access=free }}</ref> Berylliosis is typically manifested by chronic [[pulmonary fibrosis]] and, in severe cases, right sided [[heart failure]] and death.<ref>{{cite journal |last1=Chong |first1=S |last2=Lee |first2=KS |last3=Chung |first3=MJ |last4=Han |first4=J |last5=Kwon |first5=OJ |last6=Kim |first6=TS |title=Pneumoconiosis: comparison of imaging and pathologic findings. |journal=Radiographics |date=January 2006 |volume=26 |issue=1 |pages=59–77 |doi=10.1148/rg.261055070 |pmid=16418244 }}</ref>

== Characteristics ==

=== Physical properties ===
Beryllium is a steel gray and hard [[metal]] that is brittle at room temperature and has a close-packed hexagonal [[crystal structure]].<ref name="deGruyter">{{cite book
 | others=trans. rev. Eagleson, Mary
 | editor1-first=Hans-Dieter | editor1-last=Jakubke
 | editor2-first=Hans | editor2-last=Jeschkeit
 | title=Concise Encyclopedia Chemistry
 | publisher=Walter de Gruyter
 | location=Berlin
 | date=1994}}</ref> It has exceptional [[stiffness]] ([[Young's modulus]] 287&nbsp;GPa) and a [[melting point]] of 1287&nbsp;°C. The [[modulus of elasticity]] of beryllium is approximately 35% greater than that of steel. The combination of this modulus and a relatively low density results in an unusually fast [[Speed of sound|sound conduction speed]] in beryllium – about 12.9&nbsp;km/s at [[Standard temperature and pressure|ambient conditions]].
Among all metals, beryllium dissipates the most heat per unit weight, with both high specific heat ({{val|1925|u=J·kg<sup>−1</sup>·K<sup>−1</sup>}}) and thermal conductivity ({{val|216|u=W·m<sup>−1</sup>·K<sup>−1</sup>}}).
Beryllium's conductivity and relatively low coefficient of linear [[thermal expansion]] ({{val|11.4|e=-6|u=K<sup>−1</sup>}}), make it uniquely stable under extreme temperature differences.<ref name="Behrens-2003">{{Cite book| title=Landolt-Börnstein&nbsp;– Group VIII Advanced Materials and Technologies: Powder Metallurgy Data. Refractory, Hard and Intermetallic Materials| chapter=11 Beryllium|volume=2A1| doi=10.1007/10689123_36| isbn=978-3-540-42942-5| pages=667–677| editor=Beiss, P. |author=Behrens, V.|date=2003| publisher=Springer| location=Berlin| series=Landolt-Börnstein - Group VIII Advanced Materials and Technologies}}</ref>{{rp|11.1}}

=== Nuclear properties ===
Naturally occurring beryllium, save for slight contamination by the [[cosmogenic nuclide|radioisotopes created by cosmic rays]], is isotopically pure beryllium-9,<ref name="CIAAWberyllium" /> which has a [[Spin (physics)|nuclear spin]] of {{sfrac|3|2}}<sup>−</sup>.{{NUBASE2020|ref}} The inelastic scattering [[cross section (physics)|cross section]] of beryllium increases with relation to neutron energy,<ref>{{cite journal |last1=Marion |first1=J. B. |last2=Levin |first2=J. S. |last3=Cranberg |first3=L. |date=1959-06-15 |title=Elastic and Nonelastic Neutron Cross Sections for Beryllium |url=https://journals.aps.org/pr/abstract/10.1103/PhysRev.114.1584 |journal=Physical Review |volume=114 |issue=6 |pages=1584–1589 |doi=10.1103/PhysRev.114.1584|bibcode=1959PhRv..114.1584M }}</ref> allowing for significant slowing of higher-energy neutrons.<ref>{{Cite journal |last1=Kothari |first1=L. S. |last2=Singwi |first2=K. S. |date=1957-01-01 |title=Slowing down of neutrons in beryllium from 1·44 eV to thermal energy |url=https://linkinghub.elsevier.com/retrieve/pii/0891391957900335 |journal=Journal of Nuclear Energy |volume=5 |issue=3 |pages=342–356 |doi=10.1016/0891-3919(57)90033-5 |issn=0891-3919}}</ref> Therefore, it works as a [[neutron reflector]] and [[neutron moderator]]; the exact strength of neutron slowing depends on the purity and size of the crystallites in the material.<ref>{{cite journal |last1=DiJulio |first1=Douglas D. |last2=Lee |first2=Yong Joong |last3=Muhrer |first3=Gunter |date=2020-10-20 |title=Impact of crystallite size on the performance of a beryllium reflector |url=https://journals.sagepub.com/doi/full/10.3233/JNR-190135 |journal=Journal of Neutron Research |language=en |volume=22 |issue=2–3 |pages=275–279 |doi=10.3233/JNR-190135 |issn=1023-8166|arxiv=1912.03039 }}</ref>

The isotope <sup>9</sup>Be can undergo a (n, 2n) neutron reaction with fast neutrons, to produce [[beryllium-8|<sup>8</sup>Be]], which almost immediately breaks into two alpha particles. Thus, for high-energy neutrons, beryllium is a neutron multiplier, releasing more neutrons than it absorbs. This nuclear reaction is:<ref name ="BeMelurgy" />
: {{nuclide|Beryllium|9}} + n → 2 {{nuclide|Helium|4}} + 2 n

The isotope can liberate the neutron when struck by an alpha particle.<ref name="Behrens-2003" /> The nuclear reaction
: {{nuclide|Beryllium|9}} + {{nuclide|Helium|4}} → {{nuclide|Carbon|12}} + n
is strongly exothermic, liberating a fast neutron.<ref name ="BeMelurgy">{{Cite book|chapter-url=https://books.google.com/books?id=FCnUN45cL1cC&pg=PA239|page=239|chapter=Nuclear Properties|title=Beryllium its Metallurgy and Properties|publisher=University of California Press|first=Henry H.|last=Hausner|date=1965|access-date=30 October 2021|archive-date=27 July 2020|archive-url=https://web.archive.org/web/20200727101256/https://books.google.com/books?id=FCnUN45cL1cC&pg=PA239|url-status=live}}</ref>

The isotope can also release the neutron when absorbing a gamma ray of sufficient energy ([[photodisintegration]])<ref name="Byrne-2011" /> at a useful cross-section:
: {{nuclide|Beryllium|9}} + gamma  → 2 {{nuclide|Helium|4}} + n 
Thus, natural beryllium bombarded by alpha or gamma radiation from a suitable radioisotope is the most common radioisotope-powered [[neutron source]] for laboratory use.<ref name=NRC-2010>{{Cite web |date=October 13, 2010 |title=Neutron Sources |url=https://www.nrc.gov/docs/ml1122/ML11229A704.pdf |access-date=March 5, 2025 |website=[[Nuclear Regulatory Commission]]}}</ref><ref>{{Cite thesis |last=Halstead |first=Matthew R. |title=Characterization of the Energy Spectrum at the Indiana University NREP Neutron Source |date=March 2011 |access-date=5 March 2025 |publisher=Air Force Institute of Technology |url=https://www.researchgate.net/publication/235029687}}</ref>

Finally, small amounts of [[tritium]] are also liberated by the high-energy neutrons in the three-step nuclear reaction
:{{nuclide|Beryllium|9}} + n → {{nuclide|Helium|4}} + {{nuclide|Helium|6}},&nbsp;&nbsp;&nbsp; {{nuclide|Helium|6}} → {{nuclide|Lithium|6}} + β<sup>−</sup>,&nbsp;&nbsp;&nbsp; {{nuclide|Lithium|6}} + n → {{nuclide|Helium|4}} + {{nuclide|Hydrogen|3}} 
{{nuclide|Helium|6}} has a half-life of only 0.8 seconds, β<sup>−</sup> is an electron, and {{nuclide|Lithium|6}} has a high neutron absorption cross section. This is equivalent to the neutron-multiplication reaction with three output neutrons replaced by a triton, and a beta decay allowing that conversion. Tritium is a radioisotope of concern in nuclear reactor waste streams.<ref>{{cite web|last1=Tomberlin|first1=T. A.|title=Beryllium – A Unique Material in Nuclear Applications|url=https://inldigitallibrary.inl.gov/sti/2808485.pdf|archive-url=https://web.archive.org/web/20151222143703/https://inldigitallibrary.inl.gov/sti/2808485.pdf|archive-date=22 December 2015|website=Idaho National Laboratory|publisher=Idaho National Engineering and Environmental Laboratory|date=15 November 2004}}</ref>

=== Optical properties ===
As a metal, beryllium is [[transparency and translucency|transparent or translucent]] to most wavelengths of [[X-ray]]s and [[gamma ray]]s, making it useful for the output windows of [[X-ray tube]]s and other such apparatus.<ref>{{cite web |title=About Beryllium |url=https://www.energy.gov/ehss/about-beryllium |access-date=2021-12-22 |publisher=US Department of Energy |archive-date=22 December 2021 |archive-url=https://web.archive.org/web/20211222222822/https://www.energy.gov/ehss/about-beryllium |url-status=live }}</ref>

=== Isotopes and nucleosynthesis ===
{{main|Isotopes of beryllium}}

Natural beryllium is made up  of solely the stable isotope beryllium-9. Beryllium is the only [[monoisotopic element]] with an even atomic number.<ref name="CIAAWberyllium" /> 

Beryllium-7 and beryllium-8 are key intermediates in stellar nucleosynthesis, but do not last long. It is believed that the beryllium in the universe was created in the interstellar medium when [[cosmic rays]] induced fission in heavier elements found in interstellar gas and dust, a process called [[cosmic ray spallation]].<ref>{{cite book |url=https://books.google.com/books?id=ILQ7sTrRixMC&pg=PA172 |title=Physics: 1981–1990 |author=Ekspong, G. |publisher=World Scientific |date=1992 |pages=172 ff |isbn=978-981-02-0729-8 |access-date=30 October 2021 |archive-date=27 July 2020 |archive-url=https://web.archive.org/web/20200727101241/https://books.google.com/books?id=ILQ7sTrRixMC&pg=PA172 |url-status=live }}</ref><ref>{{cite journal |title=Beryllium in main-sequence stars |author=Boesgaard, A. M. |journal=Astrophysical Journal |volume=210 |date=December 1, 1976 |pages=466–474 |bibcode=1976ApJ...210..466B |doi=10.1086/154849}}</ref>

About one billionth ({{val|e=-9}}) of the primordial atoms created in the [[Big Bang nucleosynthesis]] were <sup>7</sup>Be. This is a consequence of the low density of matter when the temperature of the universe cooled enough for small nuclei to be stable. Creating such nuclei requires nuclear collisions that are rare at low density.<ref name=Peacock-1998>{{cite book |last=Peacock |first=J. A. |url=https://www.cambridge.org/core/product/identifier/9780511804533/type/book |title=Cosmological Physics |date=1998-12-28 |publisher=Cambridge University Press |isbn=978-0-521-41072-4 |edition=1 |doi=10.1017/cbo9780511804533}}</ref>{{rp|297}} Although <sup>7</sup>Be is unstable and decays by [[electron capture]] into <sup>7</sup>Li, with a half-life of 53.22 days under standard conditions, in the early universe the atoms were fully ionized and electron capture not significant. The conversion of <sup>7</sup>Be to Li was only complete near the time of [[recombination (cosmology)|recombination]].<ref>{{cite journal |last1=Cyburt |first1=Richard H. |last2=Fields |first2=Brian D. |last3=Olive |first3=Keith A. |last4=Yeh |first4=Tsung-Han |date=2016-02-23 |title=Big bang nucleosynthesis: Present status |url=https://journals.aps.org/rmp/abstract/10.1103/RevModPhys.88.015004 |journal=Reviews of Modern Physics |volume=88 |issue=1 |article-number=015004 |doi=10.1103/RevModPhys.88.015004 |arxiv=1505.01076 |bibcode=2016RvMP...88a5004C }}</ref>

The isotope <sup>7</sup>Be is also a [[cosmogenic nuclide]] and shows an atmospheric abundance inversely proportional to solar activity.<ref>{{cite journal | last1=Piñero García | first1=F. | last2=Ferro García | first2=M.A. | last3=Azahra | first3=M. | title=7Be behaviour in the atmosphere of the city of Granada January 2005 to December 2009 | journal=Atmospheric Environment | volume=47 | date=2012 | doi=10.1016/j.atmosenv.2011.11.034 | pages=84–91 }}</ref> It decays exclusively by [[electron capture]], and the 2s electrons of beryllium are the valence electrons responsible for chemical bonding. Therefore, when <sup>7</sup>Be decays by L-[[electron capture]], it does so by taking electrons from its [[atomic orbital]]s that may be participating in bonding. This makes its decay rate dependent to a measurable degree upon its chemical surroundings &nbsp;– a rare occurrence in nuclear decay.<ref>{{cite web |url=http://math.ucr.edu/home/baez/physics/ParticleAndNuclear/decay_rates.html |title=How to Change Nuclear Decay Rates |first=Bill |last=Johnson |publisher=University of California, Riverside|access-date=30 March 2008 |date=1993 |archive-date=29 June 2013 |archive-url=https://web.archive.org/web/20130629231941/http://math.ucr.edu/home/baez/physics/ParticleAndNuclear/decay_rates.html |url-status=live }}</ref>

Be-7 is also produced in cooling water of high-energy accelerators; it can be extracted from the water at high purity and sold for scientific experiments.<ref>{{Cite journal |doi=10.1021/acsomega.7b01757 |pages=3228–3234  |title=Fishing for Isotopes: Capturing Beryllium-7 from Brookhaven LINAC Isotope Producer's 300 gallons of Cooling Water |date=March 31, 2018 |journal=ACS Omega |volume=3 |issue=3 |first1=Jonathan |last1=Fitzsimmons |first2=Lisa |last2=Muench |first3=Cathy S. |last3=Cutler |pmid=31458580 |pmc=6641255}}</ref>

[[File:Solar Activity Proxies.png|class=skin-invert-image|thumb|left|upright=1.35|Plot showing variations in solar activity, including variation in sunspot number (red) and <sup>10</sup>Be concentration (blue). Note that the beryllium scale is inverted, so increases on this scale indicate lower <sup>10</sup>Be levels]]
The isotope <sup>10</sup>Be is similarly cosmogenic, and is produced in the same way - by [[cosmic ray spallation]] of nitrogen and oxygen.<ref>[https://gmd.copernicus.org/articles/16/7037/2023/gmd-16-7037-2023.pdf]</ref> Its behavior differ only because of its much longer half-life of 1.387 million years. It entirely accumulates at the [[soil]] surface and has a long [[residence time (fluid dynamics)|residence time]] before decaying to [[boron]]-10. Thus, <sup>10</sup>Be and its daughter product are used to examine natural [[soil erosion]], [[soil formation]] and the development of [[laterite|lateritic soils]], and as a [[Proxy (climate)|proxy]] for measurement of the variations in [[solar variation|solar activity]] and the age of [[ice core]]s.<ref>{{cite web |url=http://web.sahra.arizona.edu/programs/isotopes/beryllium.html |title=Beryllium: Isotopes and Hydrology |publisher=University of Arizona, Tucson |access-date=10 April 2011 |archive-date=26 May 2013 |archive-url=https://web.archive.org/web/20130526120156/http://web.sahra.arizona.edu/programs/isotopes/beryllium.html |url-status=live }}</ref> As with <sup>7</sup>Be, production of <sup>10</sup>Be is inversely related to solar activity, because increased [[solar wind]] during periods of high solar activity decreases the flux of galactic cosmic rays that reach the Earth.{{sfn|Emsley|2001|p=56}} Nuclear explosions also form <sup>10</sup>Be by the reaction of fast neutrons with <sup>13</sup>C in the carbon dioxide in air. This is one of the indicators of past activity at [[nuclear weapon test]] sites.<ref>{{cite journal |doi=10.1016/j.jenvrad.2007.07.016 |date=Feb 2008 |author=Whitehead, N |author2=Endo, S |author3=Tanaka, K |author4=Takatsuji, T |author5=Hoshi, M |author6=Fukutani, S |author7=Ditchburn, Rg |author8=Zondervan, A |title=A preliminary study on the use of (10)Be in forensic radioecology of nuclear explosion sites |volume=99 |issue=2 |pages=260–70 |pmid=17904707 |journal=Journal of Environmental Radioactivity }}</ref>

<sup>8</sup>Be is unstable but has a ground state [[Resonance (particle physics)|resonance]] with an important role in the [[triple-alpha process]] in stellar [[helium burning]]. As first proposed by British [[astronomer]] Sir [[Fred Hoyle]] based solely on astrophysical analysis, the energy levels of <sup>8</sup>Be and <sup>12</sup>C allow carbon nucleosynthesis by increasing the effective cross-section between the three alpha particles in the carbon production process. The main carbon-producing reaction in the universe is 
<math display="block">^4\textrm{He}\  +\  ^8\textrm{Be} \rightarrow\ ^{12}\textrm{C} + \gamma</math>
where <sup>4</sup>He is an alpha particle.<ref>{{cite book |url=https://books.google.com/books?id=PXGWGnPPo0gC&pg=PA223 |page=223 |title=Supernovae and nucleosynthesis |author=Arnett, David |publisher=Princeton University Press |date=1996 |isbn=978-0-691-01147-9 |access-date=30 October 2021 |archive-date=27 July 2020 |archive-url=https://web.archive.org/web/20200727094634/https://books.google.com/books?id=PXGWGnPPo0gC&pg=PA223 |url-status=live }}</ref>

The exotic isotopes <sup>11</sup>Be and <sup>14</sup>Be are known to exhibit a [[Halo nucleus|nuclear halo]]. That is, their nuclei have, respectively, 1 and 4 neutrons orbiting substantially outside the expected nuclear radius<ref>{{cite journal |doi=10.1146/annurev.ns.45.120195.003111 |doi-access=free |title=Nuclear Halos |date=1995 |author=Hansen, P. G. |author2=Jensen, A. S. |author3=Jonson, B. |journal=[[Annual Review of Nuclear and Particle Science]] |volume=45 |issue=1 |pages=591–634 |bibcode=1995ARNPS..45..591H }}</ref> and in each case the core the neutrons float around is one of <sup>10</sup>Be.

== Occurrence ==
[[File:Beryllium OreUSGOV.jpg|thumb|Beryllium ore with a [[Penny (United States coin)|U.S. penny]] for scale]]
[[File:Beryl-130023.jpg|thumb|upright=0.56|[[Emerald]] is a naturally occurring [[chemical compound|compound]] of beryllium.]]
Beryllium is found in over 100 minerals,<ref>{{cite web|url=https://www.mindat.org/chemsearch.php?cform_is_valid=1&inc=Be,&exc=&sub=Search+for+Minerals&cf_pager_page=1 |title=Search Minerals By Chemistry|website=www.mindat.org |access-date=30 October 2021 |archive-date=6 August 2021 |archive-url=https://web.archive.org/web/20210806100908/https://www.mindat.org/chemsearch.php?cform_is_valid=1&inc=Be%2C&exc=&sub=Search+for+Minerals&cf_pager_page=1 |url-status=live }}</ref> but most are uncommon to rare. The more common beryllium-containing minerals include: [[bertrandite]] ({{chem2|Be4Si2O7(OH)2}}), [[beryl]] ({{chem2|Al2Be3Si6O18}}), [[chrysoberyl]] ({{chem2|Al2BeO4}}) and [[phenakite]] ({{chem2|Be2SiO4}}). Precious forms of beryl are [[aquamarine (gemstone)|aquamarine]], [[red beryl]] and [[emerald]].<ref name="Behrens-2003" /><ref>{{cite book |chapter=Sources of Beryllium |chapter-url=https://books.google.com/books?id=3-GbhmSfyeYC&pg=PA20 |pages=20–26 |isbn=978-0-87170-721-5 |title=Beryllium chemistry and processing |author1=Walsh, Kenneth A |date=2009 |publisher=ASM International |access-date=5 January 2016 |archive-date=13 May 2016 |archive-url=https://web.archive.org/web/20160513053755/https://books.google.com/books?id=3-GbhmSfyeYC&pg=PA20 |url-status=live }}</ref><ref>{{cite book |author=Phillip Sabey |chapter=Distribution of major deposits |chapter-url=https://books.google.com/books?id=zNicdkuulE4C&pg=PA265 |pages=265–269 |isbn=978-0-87335-233-8 |title=Industrial minerals & rocks: commodities, markets, and uses |editor=Jessica Elzea Kogel |editor2=Nikhil C. Trivedi |editor3=James M. Barker |editor4=Stanley T. Krukowski |date=5 March 2006|access-date=5 January 2016 }}</ref> <!--<ref>{{cite journal
|doi=10.2138/rmg.2002.50.14
|last1=Barton|first1=M. D.
|last2=Young|first2=S.
|title=Non-pegmatitic Deposits of Beryllium: Mineralogy, Geology, Phase Equilibria and Origin
|journal=Reviews in Mineralogy and Geochemistry
|volume=50
|page=591
|year=2002}}</ref>-->
<!--
In the human body, beryllium has a concentration of 0.4 ppb by weight.<ref>{{cite web |url=http://www.webelements.com/periodicity/abundance_humans/ |title=Abundance in humans |work=Mark Winter, [[The University of Sheffield]] and WebElements Ltd, UK |publisher=WebElements |access-date=6 August 2011}}</ref>
ALSO CITED AS 0.05 ppb by weight by:
Thomas J. Glover, comp., Pocket Ref, 3rd ed. (Littleton: Sequoia, 2003), p. 324 (LCCN 2002-91021),
which in turn cites Geigy Scientific Tables, Ciba-Geigy Limited, Basel, Switzerland, 1984.
-->The green color in gem-quality forms of beryl comes from varying amounts of chromium (about 2% for emerald).{{sfn|Emsley|2001|p=58}}

The two main ores of beryllium, beryl and bertrandite, are found in Argentina, Brazil, India, Madagascar, Russia and the United States.{{sfn|Emsley|2001|p=58}} Total world reserves of beryllium ore are greater than 400,000 tonnes.{{sfn|Emsley|2001|p=58}}

The Sun has a concentration of 0.1 [[parts per billion]] (ppb) of beryllium.<ref>{{cite web |url=http://www.webelements.com/periodicity/abundance_sun/ |title=Abundance in the sun |work=Mark Winter, [[The University of Sheffield]] and WebElements Ltd, UK |publisher=WebElements |access-date=6 August 2011 |archive-url=https://web.archive.org/web/20110827013726/http://webelements.com/periodicity/abundance_sun/ |archive-date=27 August 2011 }}</ref> Beryllium has a concentration of 2 to 6 [[parts per million]] (ppm) in the Earth's crust and is the 47th-most abundant element.<ref name="Merck">{{cite book |editor1-last=O'Neil |editor1-first=Marydale J. |editor2-last=Heckelman |editor2-first=Patricia E. |editor3-last=Roman |editor3-first=Cherie B. |title=The Merck Index: An Encyclopedia of Chemicals, Drugs, and Biologicals |edition=14th |publisher=Merck Research Laboratories, Merck & Co., Inc. |location=Whitehouse Station, NJ, USA |date=2006 |isbn=978-0-911910-00-1}}</ref>{{sfn|Emsley|2001|p=59}} It is most concentrated (6 ppm) in the soils.{{sfn|Emsley|2001|p=59}} Trace amounts of <sup>9</sup>Be are found in the Earth's atmosphere.{{sfn|Emsley|2001|p=59}} The concentration of beryllium in sea water is 0.2–0.6 [[parts per trillion]].{{sfn|Emsley|2001|p=59}}<ref>{{cite web |url=http://www.webelements.com/periodicity/abundance_seawater/ |title=Abundance in oceans |work=Mark Winter, [[The University of Sheffield]] and WebElements Ltd, UK |publisher=WebElements |access-date=6 August 2011 |archive-url=https://web.archive.org/web/20110805145627/http://www.webelements.com/periodicity/abundance_seawater/ |archive-date=5 August 2011 }}</ref> In stream water, however, beryllium is more abundant, with a concentration of 0.1 ppb.<ref>{{cite web |url=http://www.webelements.com/periodicity/abundance_stream/ |title=Abundance in stream water |work=Mark Winter, [[The University of Sheffield]] and WebElements Ltd, UK |publisher=WebElements |access-date=6 August 2011 |archive-url=https://web.archive.org/web/20110804233559/http://www.webelements.com/periodicity/abundance_stream/ |archive-date=4 August 2011 }}</ref>

== Extraction ==
The extraction of beryllium from its compounds is a difficult process due to its high affinity for oxygen at elevated temperatures, and its ability to reduce water when its oxide film is removed. Currently the United States, China and Kazakhstan are the only three countries involved in the industrial-scale extraction of beryllium.<ref>{{cite web |url=https://beryllium.com/About-Beryllium/Sources%20of%20Beryllium.aspx |title=Sources of Beryllium |publisher=Materion Corporation |access-date=23 December 2016 |archive-date=24 December 2016 |archive-url=https://web.archive.org/web/20161224032844/https://beryllium.com/About-Beryllium/Sources%20of%20Beryllium.aspx |url-status=live }}</ref> Kazakhstan produces beryllium from a concentrate stockpiled before the [[Dissolution of the Soviet Union|breakup of the Soviet Union]] around 1991. This resource had become nearly depleted by the mid-2010s.<ref>[https://s3-us-west-2.amazonaws.com/prd-wret/assets/palladium/production/mineral-pubs/beryllium/myb1-2016-beryl.pdf "Beryllim"] {{webarchive|url=https://web.archive.org/web/20210703215605/https://s3-us-west-2.amazonaws.com/prd-wret/assets/palladium/production/mineral-pubs/beryllium/myb1-2016-beryl.pdf |date=3 July 2021 }} in ''2016 Minerals Yearbook''. [[USGS]] (September 2018).</ref>

Production of beryllium in Russia was halted in 1997, and is planned to be resumed in the 2020s.<ref>[https://tass.ru/ural-news/6431308 Уральский производитель изумрудов планирует выпускать стратегический металл бериллий] {{webarchive|url=https://web.archive.org/web/20211011032850/https://tass.ru/ural-news/6431308 |date=11 October 2021 }}. TASS.ru (15 May 2019)</ref><ref>{{cite web |url=http://www.eurasianbusinessbriefing.com/russia-restarts-beryllium-production-after-20-years/ |title=Russia restarts beryllium production after 20 years |work=Eurasian Business Briefing - Information for Investors |date=20 February 2015 |publisher=Eurasian Business Briefing |access-date=22 February 2018 |archive-date=31 July 2017 |archive-url=https://web.archive.org/web/20170731154457/http://www.eurasianbusinessbriefing.com/russia-restarts-beryllium-production-after-20-years/ |url-status=live }}</ref>

[[Image:Beryllium (Be).jpg|thumb|A bead of beryllium from a melt]]
Beryllium is most commonly extracted from the mineral [[beryl]], which is either [[sintering|sintered]] using an extraction agent or melted into a soluble mixture. The sintering process involves mixing beryl with [[sodium fluorosilicate]] and soda at {{convert|770|C|F}} to form [[Tetrafluoroberyllate|sodium fluoroberyllate]], [[aluminium oxide]] and [[silicon dioxide]].<ref name="deGruyter" /> [[Beryllium hydroxide]] is precipitated from a solution of sodium fluoroberyllate and [[sodium hydroxide]] in water. The extraction of beryllium using the melt method involves grinding beryl into a powder and heating it to {{convert|1650|C|F}}. The melt is quickly cooled with water and then reheated {{convert|250|to|300|C|F}} in concentrated [[sulfuric acid]], mostly yielding [[beryllium sulfate]] and [[aluminium sulfate]]. Aqueous [[ammonia]] is then used to remove the aluminium and sulfur, leaving beryllium hydroxide.<ref name="deGruyter" />

Beryllium hydroxide created using either the sinter or melt method is then converted into [[beryllium fluoride]] or [[beryllium chloride]]. To form the fluoride, aqueous [[ammonium hydrogen fluoride]] is added to beryllium hydroxide to yield a precipitate of ammonium [[tetrafluoroberyllate]], which is heated to {{convert|1000|C|F}} to form beryllium fluoride.<ref name="deGruyter" /> Heating the fluoride to {{convert|900|C|F}} with [[magnesium]] forms finely divided beryllium, and additional heating to {{convert|1300|C|F}} creates the compact metal.<ref name="deGruyter" /> Heating beryllium hydroxide forms [[beryllium oxide]], which becomes beryllium chloride when combined with carbon and chlorine. [[Electrolysis]] of molten beryllium chloride is then used to obtain the metal.<ref name="deGruyter" />

== Chemical properties ==
{{Category see also|Beryllium compounds}}
A beryllium atom has the electronic configuration [He] 2s<sup>2</sup>. The predominant [[oxidation state]] of beryllium is +2; the beryllium atom losing both of its [[valence electrons]]. Beryllium's chemical behavior is largely a result of its small [[atomic radius|atomic]] and [[ionic radius|ionic]] radii. It thus has very high [[ionization potential]]s and does not form divalent cations. Instead it forms two covalent bonds with a tendency to polymerize, as in solid {{chem2|BeCl2}}.<ref name="deGruyter"/>{{rp|37}} Its chemistry has similarities to that of aluminium, an example of a [[diagonal relationship]].<ref name="Greenwood"/>{{rp|107}}  
In the other direction, beryllium is attracted to electron density, generating intermolecular forces similar to [[hydrogen bonding]].<ref>{{Citation |last1=Montero-Campillo |first1=M. Merced |title=Chapter Three - The beryllium bond |date=2019-01-01 |url=https://www.sciencedirect.com/science/article/pii/S0898883818300394 |work=Advances in Inorganic Chemistry |volume=73 |pages=73–121 |editor-last=van Eldik |editor-first=Rudi |series=Computational Chemistry |publisher=Academic Press |language=en |access-date=2022-10-26 |last2=Mó |first2=Otilia |last3=Yáñez |first3=Manuel |last4=Alkorta |first4=Ibon |last5=Elguero |first5=José |doi=10.1016/bs.adioch.2018.10.003 |s2cid=140062833 |editor2-last=Puchta |editor2-first=Ralph}}</ref>

At room temperature, the surface of beryllium forms a 1−10&nbsp;nm-thick oxide [[Passivation (chemistry)|passivation]] layer that prevents further reactions with air, except for gradual thickening of the oxide up to about 25&nbsp;nm. When heated above about 500&nbsp;°C, oxidation into the bulk metal progresses along grain boundaries.<ref name="Tomastik2005">{{cite journal |last1=Tomastik |first1=C. |last2=Werner |first2=W. |last3=Stori |first3=H. |title=Oxidation of beryllium—a scanning Auger investigation |journal=Nucl. Fusion |date=2005 |volume=45 |issue=9 |page=1061 |doi=10.1088/0029-5515/45/9/005 |bibcode=2005NucFu..45.1061T |s2cid=111381179 |url=https://iopscience.iop.org/article/10.1088/0029-5515/45/9/005}}</ref> Once the metal is ignited in air by heating above the oxide melting point around 2500&nbsp;°C, beryllium burns brilliantly,<ref name="Maček-1969" /> forming a mixture of [[beryllium oxide]] and [[beryllium nitride]]. Beryllium dissolves readily in non-[[oxidizing acid]]s, such as HCl and diluted {{chem2|H2SO4}}, but not in [[nitric acid]] or water as this forms the oxide. This behavior is similar to that of aluminium. Beryllium also dissolves and reacts with alkali solutions.<ref name="deGruyter" /><ref name="Greenwood">{{Greenwood&Earnshaw}}</ref>{{rp|112}}  

Binary compounds of beryllium(II) are polymeric in the solid state. {{chem2|BeF2|link=Beryllium fluoride}} has a [[silica]]-like structure with corner-shared {{chem2|BeF4}} tetrahedra. {{chem2|BeCl2|link=Beryllium chloride}} and {{chem2|BeBr2|link=Beryllium bromide}} have chain structures with edge-shared tetrahedra. [[Beryllium oxide]], BeO, is a white [[refractory]] solid which has a [[zinc sulfide|wurtzite]] crystal structure and a thermal conductivity as high as some metals. BeO is [[amphoteric]]. [[Beryllium sulfide]], [[Beryllium selenide|selenide]] and [[Beryllium telluride|telluride]] are known, all having the [[Cubic crystal system#Zincblende structure|zincblende structure]].<ref name="Wiberg&Holleman">{{Cite book |author=Wiberg, Egon |author2=Holleman, Arnold Frederick |date=2001 |title=Inorganic Chemistry |publisher=Elsevier |isbn=978-0-12-352651-9}}</ref> [[Beryllium nitride]], {{chem2|Be3N2}}, is a high-melting-point compound which is readily hydrolyzed. [[Beryllium azide]], {{chem2|BeN6}} is known and [[beryllium phosphide]], {{chem2|Be3P2}} has a similar structure to {{chem2|Be3N2}}. A number of beryllium [[boride]]s are known, such as {{chem2|Be5B}}, {{chem2|Be4B}}, {{chem2|Be2B}}, {{chem2|BeB2}}, {{chem2|BeB6}} and {{chem2|BeB12}}. [[Beryllium carbide]], {{chem2|Be2C}}, is a refractory brick-red compound that reacts with water to give [[methane]].<ref name="Wiberg&Holleman" /> Beryllium [[silicide|silicides]] have been identified in the form of variously sized [[Nanocluster|nanoclusters]],<ref>{{Cite journal |last1=Fioressi |first1=Silvina |last2=Bacelo |first2=Daniel E. |last3=Binning |first3=R.C. |date=June 2012 |title=A DFT study of dodecahedral beryllium silicide cage clusters |url=https://linkinghub.elsevier.com/retrieve/pii/S000926141200468X |journal=Chemical Physics Letters |language=en |volume=537 |pages=75–79 |doi=10.1016/j.cplett.2012.04.002|bibcode=2012CPL...537...75F }}</ref> formed through a spontaneous reaction between pure beryllium and silicon.<ref>{{Cite journal |last1=Hite |first1=D.A. |last2=Tang |first2=S.-J. |last3=Sprunger |first3=P.T. |date=January 2003 |title=Reactive epitaxy of beryllium on Si(111)-(7×7) |url=https://linkinghub.elsevier.com/retrieve/pii/S0009261402016378 |journal=Chemical Physics Letters |language=en |volume=367 |issue=1–2 |pages=129–135 |doi=10.1016/S0009-2614(02)01637-8|bibcode=2003CPL...367..129H }}</ref> The halides {{chem2|BeX2}} (X = F, Cl, Br, and I) have a linear monomeric molecular structure in the gas phase.<ref name="Greenwood" />{{rp|117}}

Lower oxidation states complexes of beryllium are exceedingly rare. For example, a stable complex with a Be-Be bond, which formally features beryllium in the +1 oxidation state, has been described.<ref name="BCWABe(I)">{{Cite journal |last1=Boronski |first1=Josef T. |last2=Crumpton |first2=Agamemnon E. |last3=Wales |first3=Lewis L. |last4=Aldridge |first4=Simon |date=2023-06-16 |title=Diberyllocene, a stable compound of Be(I) with a Be–Be bond |url=https://www.science.org/doi/10.1126/science.adh4419 |journal=Science |language=en |volume=380 |issue=6650 |pages=1147–1149 |doi=10.1126/science.adh4419 |pmid=37319227 |bibcode=2023Sci...380.1147B |s2cid=259166086 |issn=0036-8075}}</ref> Beryllium in the 0 oxidation state is also known in a complex with a Mg-Be bond.<ref name="Be(0)"/> 

=== Aqueous solutions ===
[[File:Beacetate.png|class=skin-invert-image|thumb|left|160px|Schematic structure of [[basic beryllium acetate]]]] 
[[File:BeHydrolysis.png|class=skin-invert-image|thumb|left|190px|Beryllium hydrolysis. Water molecules attached to Be are omitted in this diagram]]
[[File:Be3OHW6.svg|class=skin-invert-image|thumb|left|200px|Structure of the trimeric hydrolysis product of beryllium(II)]]

Solutions of beryllium salts, such as [[beryllium sulfate]] and [[beryllium nitrate]], are acidic because of hydrolysis of the {{chem2|[Be(H2O)4](2+)}} ion. The concentration of the first hydrolysis product, {{chem2|[Be(H2O)3(OH)]+}}, is less than 1% of the beryllium concentration. The most stable hydrolysis product is the [[trimer (chemistry)|trimeric]] ion {{chem2|[Be3(OH)3(H2O)6](3+)}}. [[Beryllium hydroxide]], {{chem2|Be(OH)2}}, is insoluble in water at pH 5 or more. Consequently, beryllium compounds are generally insoluble at biological pH. Because of this, inhalation of beryllium metal dust leads to the development of the fatal condition of [[berylliosis]]. {{chem2|Be(OH)2}} dissolves in strongly [[Alkalinity|alkaline]] solutions.<ref name="Lucia">{{cite journal |last1=Alderghi |first1=Lucia |last2=Gans |first2=Peter |last3=Midollini |first3=Stefano |last4=Vacca |first4=Alberto |date=2000 |editor1-last=Sykes |editor1-first=A.G |editor2-last=Cowley |editor2-first=Alan H. |title=Aqueous Solution Chemistry of Beryllium |journal=Advances in Inorganic Chemistry |location=San Diego |publisher=Academic Press |volume=50 |pages=109–172 |doi=10.1016/S0898-8838(00)50003-8 |isbn=978-0-12-023650-3 }}</ref>

Beryllium(II) forms few complexes with monodentate ligands because the water molecules in the aquo-ion, {{chem2|[Be(H2O)4](2+)}} are bound very strongly to the beryllium ion. Notable exceptions are the series of water-soluble complexes with the [[fluoride]] ion:<ref>{{cite book|doi=10.1016/S0065-2792(08)60008-4 |author=Bell, N.A. |isbn=978-0-12-023614-5 |title=Advances in Inorganic Chemistry and Radiochemistry |volume=14 |date=1972 |publisher=Academic Press |location=New York |pages=256–277 }}</ref> 
: {{chem2|[Be(H2O)4](2+) + ''n'' F- <-> Be[(H2O)_{2-''n''}F_{''n''}](2-) + ''n'' H2O}}

Beryllium(II) forms many complexes with bidentate ligands containing oxygen-donor atoms.<ref name="Lucia"/> The species {{chem2|[Be3O(H2PO4)6](2-)}} is notable for having a 3-coordinate oxide ion at its center. [[Basic beryllium acetate]], {{chem2|Be4O(OAc)6}}, has an oxide ion surrounded by a tetrahedron of beryllium atoms.<ref>{{Cite journal |last1=Raymond |first1=Onyekachi |last2=Perera |first2=Lakshika |last3=Brothers |first3=Penelope J. |last4=Henderson |first4=William |last5=Plieger |first5=Paul G. |date=2015 |title=The chemistry and metallurgy of beryllium |url=https://nzic.org.nz/unsecure_files/cinz/2015-79-3.pdf |journal=Chemistry in New Zealand |volume=79 |issue=3 |pages=137–143}}</ref>

With organic ligands, such as the [[malonate]] ion, the acid deprotonates when forming the complex. The donor atoms are two oxygens.
: {{chem2|H2A + [Be(H2O)4](2+) <-> [BeA(H2O)2] + 2 H+ + 2 H2O}}
: {{chem2|H2A + [BeA(H2O)2] <-> [BeA2](2-) + 2 H+ + 2 H2O}}

The formation of a complex is in competition with the metal ion-hydrolysis reaction and mixed complexes with both the anion and the hydroxide ion are also formed. For example, derivatives of the cyclic trimer are known, with a bidentate ligand replacing one or more pairs of water molecules.<ref name="KSMisleadingTitle">{{cite journal |last1=Kumberger |first1=Otto |last2=Schmidbaur |first2=Hubert |date=December 1993 |title=Warum ist Beryllium so toxisch? |url=https://onlinelibrary.wiley.com/doi/10.1002/ciuz.19930270611 |journal=Chemie in unserer Zeit |language=de |volume=27 |issue=6 |pages=310–316 |doi=10.1002/ciuz.19930270611 |issn=0009-2851 }}</ref>

Aliphatic [[hydroxycarboxylic acid]]s such as [[glycolic acid]] form rather weak monodentate complexes in solution, in which the hydroxyl group remains intact. In the solid state, the hydroxyl group may deprotonate: a hexamer, {{chem2|Na4[Be6(OCH2(O)O)6]}}, was isolated long ago.<ref name="KSMisleadingTitle" /><ref>{{cite journal |last1=Rosenheim |first1=Arthur |last2=Lehmann |first2=Fritz |date=1924 |title=Über innerkomplexe Beryllate |journal=Liebigs Ann. Chem. |volume=440 |pages=153–166 |doi=10.1002/jlac.19244400115 }}</ref> Aromatic hydroxy ligands (i.e. [[phenol]]s) form relatively strong complexes. For example, log K<sub>1</sub> and log K<sub>2</sub> values of 12.2 and 9.3 have been reported for complexes with [[Tiron (chemical)|tiron]].<ref name="KSMisleadingTitle" /><ref>{{cite journal |last1=Schmidt |first1=M. |last2=Bauer |first2=A. |last3=Schier |first3=A. |last4=Schmidtbauer |first4=H |date=1997 |title=Beryllium Chelation by Dicarboxylic Acids in Aqueous Solution |journal=Inorganic Chemistry |volume=53b |issue=10 |pages=2040–2043 |doi=10.1021/ic961410k |pmid=11669821 }}</ref>

Beryllium has generally a rather poor affinity for [[ammine]] ligands.<ref name="KSMisleadingTitle" /><ref name="MDCBMVChelate">{{cite journal |last1=Mederos |first1=A. |last2=Dominguez |first2=S. |last3=Chinea |first3=E. |last4=Brito |first4=F. |last5=Middolini |first5=S. |last6=Vacca |first6=A. |date=1997 |title=Recent aspects of the coordination chemistry of the very toxic cation beryllium(II): The search for sequestering agents |journal=Bol. Soc. Chil. Quim. |volume=42 |page=281 }}</ref> There are many early reports of complexes with amino acids, but unfortunately they are not reliable as the concomitant hydrolysis reactions were not understood at the time of publication. Values for log β of ca. 6 to 7 have been reported. The degree of formation is small because of competition with hydrolysis reactions.<ref name="KSMisleadingTitle" /><ref name="MDCBMVChelate" />

=== Organic chemistry ===
{{main article|Organoberyllium chemistry}}

Organometallic beryllium compounds are known to be highly reactive.<ref name="naglav">{{cite journal |title=Off the Beaten Track—A Hitchhiker's Guide to Beryllium Chemistry |author=Naglav, D. |author2=Buchner, M. R. |author3=Bendt, G. |author4=Kraus, F. |author5=Schulz, S. |journal=Angew. Chem. Int. Ed. |year=2016 |volume= 55 |issue=36 |pages= 10562–10576 |doi=10.1002/anie.201601809 |pmid=27364901 |bibcode=2016ACIE...5510562N }}</ref> Examples of known organoberyllium compounds are dineopentylberyllium,<ref>{{cite journal |doi=10.1039/J19710001308 |title=Preparation of base-free beryllium alkyls from trialkylboranes. Dineopentylberyllium, bis((trimethylsilyl)methyl)beryllium, and an ethylberyllium hydride |year=1971 |last1=Coates |first1=G. E. |last2=Francis |first2=B. R. |journal=Journal of the Chemical Society A: Inorganic, Physical, Theoretical |page=1308}}</ref> [[beryllocene]] ({{chem2|Cp2Be}}),<ref>{{cite journal |doi=10.1002/cber.19590920233 |title=Über Aromatenkomplexe von Metallen, XXV. Di-cyclopentadienyl-beryllium |year=1959 |last1=Fischer |first1=Ernst Otto |last2=Hofmann |first2=Hermann P. |journal=Chemische Berichte |volume=92 |page=482 |issue=2 }}</ref><ref>{{cite journal |doi=10.1071/CH9841601 |title=A precise low-temperature crystal structure of Bis(cyclopentadienyl)beryllium |year=1984 |last1=Nugent |first1=K. W. |last2=Beattie |first2=J. K. |last3=Hambley |first3=T. W. |last4=Snow |first4=M. R. |s2cid=94408686 |journal=Australian Journal of Chemistry |volume=37 |page=1601 |issue=8}}</ref><ref>{{cite journal |doi=10.1016/S0022-328X(00)92065-5 |title=The molecular structure of beryllocene, (C<sub>5</sub>H<sub>5</sub>)<sub>2</sub>Be. A reinvestigation by gas phase electron diffraction |year=1979 |last1=Almenningen |first1=A. |journal=Journal of Organometallic Chemistry |volume=170 |page=271 |issue=3 |last2=Haaland |first2=Arne |last3=Lusztyk |first3=Janusz}}</ref><ref>{{cite journal |doi=10.1107/S0567740872004820 |title=Crystal structure of bis(cyclopentadienyl)beryllium at −120&nbsp;°C |year=1972 |last1=Wong |first1=C. H. |last2=Lee |first2=T. Y. |last3=Chao |first3=K. J. |last4=Lee |first4=S. |journal=Acta Crystallographica Section B |volume=28 |page=1662 |issue=6 |bibcode=1972AcCrB..28.1662W }}</ref> diallylberyllium (by exchange reaction of diethyl beryllium with triallyl boron),<ref>{{cite journal |doi=10.1002/zaac.19744050111 |title=Ein Beitrag zur Existenz von Allylberyllium- und Allylaluminiumverbindungen |language=de |year=1974 |last1=Wiegand |first1=G. |last2=Thiele |first2=K.-H. |journal=Zeitschrift für Anorganische und Allgemeine Chemie |volume=405 |issue=1 |pages=101–108 |bibcode=1974ZAACh.405..101W }}</ref> bis(1,3-trimethylsilylallyl)beryllium,<ref>{{cite journal |doi=10.1002/anie.201001866 |pmid=20575128 |title=Bis(1,3-trimethylsilylallyl)beryllium |year=2010 |last1=Chmely |first1=Stephen C. |last2=Hanusa |first2=Timothy P. |last3=Brennessel |first3=William W. |journal=Angewandte Chemie International Edition |volume=49 |issue=34 |pages=5870–5874 |bibcode=2010ACIE...49.5870C }}</ref> Be([[Mesitylene|mes]])<sub>2</sub>,<ref name="naglav" /> and (beryllium(I) complex) diberyllocene.<ref name="BCWABe(I)" /> Ligands can also be aryls<ref>{{cite journal |doi=10.1021/ic00061a031 |title=Synthesis and structural characterization of the beryllium compounds [Be(2,4,6-Me<sub>3</sub>C<sub>6</sub>H<sub>2</sub>)<sub>2</sub>(OEt<sub>2</sub>)], [Be{O(2,4,6-tert-Bu<sub>3</sub>C<sub>6</sub>H<sub>2</sub>)}<sub>2</sub>(OEt<sub>2</sub>)], and [Be{S(2,4,6-tert-Bu<sub>3</sub>C<sub>6</sub>H<sub>2</sub>)}<sub>2</sub>(THF)]⋅PhMe and determination of the structure of [BeCl<sub>2</sub>(OEt<sub>2</sub>)<sub>2</sub>] |year=1993 |last1=Ruhlandt-Senge |first1=Karin |last2=Bartlett |first2=Ruth A. |last3=Olmstead |first3=Marilyn M. |last4=Power |first4=Philip P. |journal=Inorganic Chemistry |volume=32 |issue=9 |pages=1724–1728}}</ref> and alkynyls.<ref>{{cite journal |doi=10.1016/S0022-328X(00)87485-9 |title=The crystal structure of dimeric methyl-1-propynyl- beryllium-trimethylamine |year=1971 |last1=Morosin |first1=B. |journal=Journal of Organometallic Chemistry |volume=29 |pages=7–14 |last2=Howatson |first2=J. }}</ref>

== History ==
The mineral [[beryl]], which contains beryllium, has been used at least since the [[Ptolemaic dynasty]] of Egypt.{{sfn|Weeks|1968|p=535}} The [[Papyrus Graecus Holmiensis]], written in the third or fourth century CE, contains notes on how to prepare artificial emerald and beryl.{{sfn|Weeks|1968|p=536}}

[[File:Louis Nicolas Vauquelin.jpg|thumb|upright|[[Louis-Nicolas Vauquelin]] discovered beryllium]]
Early analyses of emeralds and beryls by [[Martin Heinrich Klaproth]], [[Torbern Olof Bergman]], [[Franz Karl Achard]], and {{ill|Johann Jakob Bindheim|de}} always yielded similar elements, leading to the mistaken conclusion that both substances are [[aluminium silicate]]s.{{sfn|Weeks|1968|p=537}} Mineralogist [[René Just Haüy]] discovered that both crystals are geometrically identical, and he asked chemist [[Louis-Nicolas Vauquelin]] for a chemical analysis.{{sfn|Weeks|1968|p=535}}

In a 1798 paper read before the [[Institut de France]], Vauquelin reported that he found a new "earth" by dissolving [[aluminium hydroxide]] from emerald and beryl in an additional [[alkali]].<ref>{{cite journal |journal=Annales de Chimie |first=Louis-Nicolas |last=Vauquelin |title=De l'Aiguemarine, ou Béril; et découverie d'une terre nouvelle dans cette pierre |trans-title=Aquamarine or beryl; and discovery of a new earth in this stone |date=1798 |volume=26 |pages=155–169 |url=https://books.google.com/books?id=dB8AAAAAMAAJ&pg=RA1-PA155 |access-date=5 January 2016|archive-date=27 April 2016 |archive-url=https://web.archive.org/web/20160427192005/https://books.google.com/books?id=dB8AAAAAMAAJ&pg=RA1-PA155 |url-status=live }}</ref> The editors of the journal ''[[Annales de chimie et de physique]]'' named the new earth "glucine" for the sweet taste of some of its compounds.<ref>In a footnote on [https://books.google.com/books?id=dB8AAAAAMAAJ&pg=RA1-PA169 page 169] {{webarchive |url=https://web.archive.org/web/20160623233202/https://books.google.com/books?id=dB8AAAAAMAAJ&pg=RA1-PA169 |date=23 June 2016 }} of (Vauquelin, 1798), the editors write: "(1) La propriété la plus caractéristique de cette terre, confirmée par les dernières expériences de notre collègue, étant de former des sels d'une saveur sucrée, nous proposons de l'appeler ''glucine'', de γλυκυς, ''doux'', γλυκύ, ''vin doux'', γλυκαιτω, ''rendre doux'' ... ''Note des Rédacteurs''." ((1) The most characteristic property of this earth, confirmed by the recent experiments of our colleague [Vauquelin], being to form salts with a sweet taste, we propose to call it ''glucine'' from γλυκυς, ''sweet'', γλυκύ, ''sweet wine'', γλυκαιτω, ''to make sweet'' ... ''Note of the editors''.)</ref>{{Sfn|Weeks|1968|p=538}} The name ''beryllium'' was first used by [[Friedrich Wöhler]] in 1828.<ref name=NameGame-2023>{{cite journal |last=Miśkowiec |first=Paweł |date=April 2023 |title=Name game: the naming history of the chemical elements—part 1—from antiquity till the end of 18th century |journal=Foundations of Chemistry |language=en |volume=25 |issue=1 |pages=29–51 |doi=10.1007/s10698-022-09448-5 |issn=1386-4238 |doi-access=free }}</ref><ref name="Wöhler"/> Both beryllium and glucinum were used concurrently until 1949, when the [[IUPAC]] adopted beryllium as the standard name of the element.<ref>{{cite journal |last=Robinson |first=Ann E. |date=2019-12-06 |title=Order From Confusion: International Chemical Standardization and the Elements, 1947-1990 |url=https://riviste.fupress.net/index.php/subs/article/view/498 |journal=Substantia |language=en |pages=83–99 Pages |doi=10.13128/SUBSTANTIA-498 }}</ref><ref>Holden, N. E. (2019). History of the origin of the chemical elements and their discoverers (No. BNL-211891-2019-COPA). Brookhaven National Lab.(BNL), Upton, NY (United States).</ref>

[[File:Friedrich Wöhler Stich.jpg|thumb|left|upright|[[Friedrich Wöhler]] was one of the men who independently isolated beryllium]]
[[Friedrich Wöhler]]<ref name="Wöhler">{{cite journal |journal=Annalen der Physik und Chemie |date=1828 |title=Ueber das Beryllium und Yttrium |trans-title=On beryllium and yttrium |first=Friedrich |last=Wöhler |author-link=Friedrich Wöhler |volume=89 |issue=8 |pages=577–582 |url=https://books.google.com/books?id=YW0EAAAAYAAJ&pg=PA577 |doi=10.1002/andp.18280890805 |bibcode=1828AnP....89..577W |access-date=5 January 2016 |archive-date=27 May 2016 |archive-url=https://web.archive.org/web/20160527114751/https://books.google.com/books?id=YW0EAAAAYAAJ&pg=PA577 |url-status=live }}</ref> and [[Antoine Bussy]]<ref>{{cite journal |journal=Journal de Chimie Médicale |url=https://books.google.com/books?id=pwUFAAAAQAAJ&pg=PA456 |pages=456–457 |first=Antoine |last=Bussy |title=D'une travail qu'il a entrepris sur le glucinium |date=1828 |issue=4 |access-date=5 January 2016 |archive-date=22 May 2016 |archive-url=https://web.archive.org/web/20160522013803/https://books.google.com/books?id=pwUFAAAAQAAJ&pg=PA456 |url-status=live }}</ref> independently isolated beryllium in 1828 by the [[chemical reaction]] of metallic [[potassium]] with [[beryllium chloride]], as follows:
: {{chem2|BeCl2 + 2 K -> 2 KCl + Be}}

Using an alcohol lamp, Wöhler heated alternating layers of beryllium chloride and potassium in a wired-shut platinum crucible. The above reaction immediately took place and caused the crucible to become white hot. Upon cooling and washing the resulting gray-black powder, he saw that it was made of fine particles with a dark metallic luster.{{sfn|Weeks|1968|p=539}} The highly reactive potassium had been produced by the [[electrolysis]] of its compounds.<ref name="Enghag2004">{{cite book |last=Enghag |first= P. |date=2004 |url=https://archive.org/details/encyclopediaofel0000engh | title=Encyclopedia of the elements | publisher=Wiley-VCH Weinheim | isbn=978-3-527-30666-4 | chapter=11. Sodium and Potassium }}</ref> He did not succeed to melt the beryllium particles.{{sfn|Weeks|1968|p=539}}

The direct electrolysis of a molten mixture of [[beryllium fluoride]] and [[sodium fluoride]] by [[Paul Lebeau]] in 1898 resulted in the first pure (99.5 to 99.8%) samples of beryllium.{{sfn|Weeks|1968|p=539}} However, industrial production started only after the First World War. The original industrial involvement included subsidiaries and scientists related to the [[Union Carbide|Union Carbide and Carbon Corporation]] in Cleveland, Ohio, and [[Siemens & Halske]] AG in Berlin. In the US, the process was ruled by Hugh S. Cooper, director of The Kemet Laboratories Company. In Germany, the first commercially successful process for producing beryllium was developed in 1921 by [[Alfred Stock]] and [[Hans Goldschmidt]].<ref>{{cite conference |last=Boillat |first=Johann |date=27 August 2016 |title=From Raw Material to Strategic Alloys. The Case of the International Beryllium Industry (1919–1939) |url=https://www.researchgate.net/publication/309154800|conference=1st World Congress on Business History, At Bergen – Norway |doi=10.13140/rg.2.2.35545.11363 |access-date=30 October 2021 |archive-date=30 October 2021 |archive-url=https://web.archive.org/web/20211030014300/https://www.researchgate.net/publication/309154800_From_Raw_Material_to_Strategic_Alloys_The_Case_of_the_International_Beryllium_Industry_1919-1939 |url-status=live }}</ref>

A sample of beryllium was bombarded with [[alpha ray]]s from the decay of [[radium]] in a 1932 experiment by [[James Chadwick]] that uncovered the existence of the [[neutron]].{{sfn|Emsley|2001|p=58}} This same method is used in one class of radioisotope-based laboratory [[neutron source]]s that produce 30 neutrons for every million α particles.<ref name="Merck" />

Beryllium production saw a rapid increase during World War II due to the rising demand for hard beryllium-copper alloys and [[phosphor]]s for [[fluorescent light]]s. Most early fluorescent lamps used [[zinc orthosilicate]] with varying content of beryllium to emit greenish light. Small additions of magnesium [[tungstate]] improved the blue part of the spectrum to yield an acceptable white light. Halophosphate-based phosphors replaced beryllium-based phosphors after beryllium was found to be toxic.<ref>{{cite book |chapter=A Review of Early Inorganic Phosphors |chapter-url=https://books.google.com/books?id=klE5qGAltjAC&pg=PA98 |page=98 |title=Revolution in lamps: a chronicle of 50 years of progress |isbn=978-0-88173-378-5 |author1=Kane, Raymond |author2=Sell, Heinz |date=2001 |publisher=Fairmont Press |access-date=5 January 2016 |archive-date=7 May 2016 |archive-url=https://web.archive.org/web/20160507023648/https://books.google.com/books?id=klE5qGAltjAC&pg=PA98 |url-status=live }}</ref>

Electrolysis of a mixture of [[beryllium fluoride]] and [[sodium fluoride]] was used to isolate beryllium during the 19th century. The metal's high melting point makes this process more energy-consuming than corresponding processes used for the [[alkali metals]]. Early in the 20th century, the production of beryllium by the thermal decomposition of [[beryllium iodide]] was investigated following the success of a similar process for the production of [[zirconium]], but this process proved to be uneconomical for volume production.<ref>{{cite journal |doi=10.1080/08827508808952633 |title=Beryllium Extraction&nbsp;– A Review |date=1988 |author=Babu, R. S. |journal=Mineral Processing and Extractive Metallurgy Review |volume=4 |pages=39–94 |last2=Gupta |first2=C. K.}}</ref>

Pure beryllium metal did not become readily available until 1957, even though it had been used as an alloying metal to harden and toughen copper much earlier.{{sfn|Emsley|2001|p=58}} Beryllium could be produced by reducing beryllium compounds such as [[beryllium chloride]] with metallic potassium or sodium. Currently, most beryllium is produced by reducing beryllium fluoride with [[magnesium]].<ref name="crc84hammond">{{cite book |last=Hammond |first=C.R. |title=CRC handbook of chemistry and physics |url=https://books.google.com/books?id=q2qJId5TKOkC&pg=PP9 |access-date=18 July 2019 |edition=84th |year=2003 |publisher=CRC Press |location=Boca Raton, FL |isbn=978-0-8493-0595-5|pages=4–5 |contribution=The Elements |archive-date=13 March 2020 |archive-url=https://web.archive.org/web/20200313124136/https://books.google.com/books?id=q2qJId5TKOkC&pg=PP9 |url-status=live }}</ref> The price on the American market for [[Casting (metalworking)|vacuum-cast]] beryllium ingots was about $338 per pound ($745 per kilogram) in 2001.<ref name="USGS">{{cite web |url=https://minerals.usgs.gov/minerals/pubs/commodity/beryllium/|title=Beryllium Statistics and Information |publisher=United States Geological Survey |access-date=18 September 2008 |archive-date=16 September 2008 |archive-url=https://web.archive.org/web/20080916114659/http://minerals.usgs.gov/minerals/pubs/commodity/beryllium/ |url-status=live }}</ref>

Between 1998 and 2008, the world's production of beryllium had decreased from 343 to about 200 [[tonne]]s. It then increased to 230 metric tons by 2018, of which 170 tonnes came from the United States.<ref name="USGSMCS2000">{{cite web |url=https://minerals.usgs.gov/minerals/pubs/commodity/beryllium/100300.pdf |title=Commodity Summary: Beryllium |publisher=United States Geological Survey |access-date=16 May 2010 |archive-date=1 June 2010 |archive-url=https://web.archive.org/web/20100601210148/http://minerals.usgs.gov/minerals/pubs/commodity/beryllium/100300.pdf |url-status=live }}</ref><ref name="USGSMCS2010">{{cite web |url=https://minerals.usgs.gov/minerals/pubs/commodity/beryllium/mcs-2010-beryl.pdf |title=Commodity Summary 2000: Beryllium|publisher=United States Geological Survey|access-date=16 May 2010|archive-date=16 July 2010|archive-url=https://web.archive.org/web/20100716091446/http://minerals.usgs.gov/minerals/pubs/commodity/beryllium/mcs-2010-beryl.pdf |url-status=live }}</ref>

=== Etymology ===
Beryllium was named for the semiprecious mineral [[beryl]], from which it was first isolated.<ref>{{cite web |url=https://www.etymonline.com/word/beryllium |title=etymology online |access-date=30 October 2021 |archive-date=30 October 2020 |archive-url=https://web.archive.org/web/20201030044456/https://www.etymonline.com/word/beryllium |url-status=live }}</ref><ref>{{cite encyclopedia |url=https://www.britannica.com/science/beryllium |title=Encyclopædia Britannica |encyclopedia=Encyclopedia Britannica |access-date=30 October 2021 |archive-date=23 October 2021 |archive-url=https://web.archive.org/web/20211023084814/https://www.britannica.com/science/beryllium |url-status=live }}</ref><ref>{{cite web |url=http://www.elementalmatter.info/element-beryllium.htm |title=Elemental Matter |access-date=30 October 2021 |archive-date=29 November 2020 |archive-url=https://web.archive.org/web/20201129001922/http://www.elementalmatter.info/element-beryllium.htm |url-status=live }}</ref> Martin Klaproth, having independently determined that beryl and emerald share an element, preferred the name "beryllina" due to the fact that [[yttria]] also formed sweet salts.<ref>Klaproth, Martin Heinrich, ''Beitrage zur Chemischen Kenntniss der Mineralkörper'' (Contribution to the chemical knowledge of mineral substances), vol. 3, (Berlin, (Germany): Heinrich August Rottmann, 1802), [https://books.google.com/books?id=8A8KAAAAIAAJ&pg=PA78 pages 78–79] {{webarchive |url=https://web.archive.org/web/20160426233710/https://books.google.com/books?id=8A8KAAAAIAAJ&pg=PA78 |date=26 April 2016 }}: "Als Vauquelin der von ihm im Beryll und Smaragd entdeckten neuen Erde, wegen ihrer Eigenschaft, süsse Mittelsalze zu bilden, den Namen ''Glykine'', ''Süsserde'', beilegte, erwartete er wohl nicht, dass sich bald nachher eine anderweitige Erde finden würde, welche mit völlig gleichem Rechte Anspruch an diesen Namen machen können. Um daher keine Verwechselung derselben mit der Yttererde zu veranlassen, würde es vielleicht gerathen seyn, jenen Namen ''Glykine'' aufzugeben, und durch Beryllerde (''Beryllina'') zu ersetzen; welche Namensveränderung auch bereits vom Hrn. Prof. Link, und zwar aus dem Grunde empfohlen worden, weil schon ein Pflanzengeschlecht ''Glycine'' vorhanden ist." (When Vauquelin conferred – on account of its property of forming sweet salts – the name ''glycine'', ''sweet-earth'', on the new earth that had been found by him in beryl and smaragd, he certainly didn't expect that soon thereafter another earth would be found which with fully equal right could claim this name. Therefore, in order to avoid confusion of it with yttria-earth, it would perhaps be advisable to abandon this name ''glycine'' and replace it with beryl-earth (''beryllina''); which name change was also recommended by Prof. Link, and for the reason that a genus of plants, ''Glycine'', already exists.)</ref><ref name=NameGame-2023/>

Although [[Humphry Davy]] failed to isolate it, he proposed the name ''glucium'' for the new metal, derived from the name ''glucina'' for the earth it was found in; altered forms of this name, ''glucinium'' or ''glucinum'' (symbol Gl) continued to be used into the 20th century.<ref>{{cite web |title=4. Beryllium - Elementymology & Elements Multidict |url=https://elements.vanderkrogt.net/element.php?sym=Be |access-date=2024-10-15 |website=elements.vanderkrogt.net }}</ref>

== Applications ==

=== Radiation windows ===
[[File:Beryllium target.jpg|thumb|Beryllium target which converts a proton beam into a neutron beam<ref>{{cite journal |last1=D K Bewley |last2=J -P Meulders |last3=M Octave-Prignot |last4=B C Page |date=1980-09-01 |title=Neutron beams from protons on beryllium |url=https://iopscience.iop.org/article/10.1088/0031-9155/25/5/005 |journal=Physics in Medicine & Biology |volume=25 |issue=5 |pages=887–892 |doi=10.1088/0031-9155/25/5/005 |pmid=6256782 |bibcode=1980PMB....25..887B |issn=0031-9155 }}</ref>]]
[[File:Be foil square.jpg|thumb|right|A square beryllium foil mounted in a steel case to be used as a window between a vacuum chamber and an [[X-ray microscope]]. Beryllium is highly transparent to X-rays owing to its low [[atomic number]].]]
Because of its low atomic number and very low absorption for X-rays, the oldest and still one of the most important applications of beryllium is in radiation windows for [[X-ray tube]]s.{{sfn|Emsley|2001|p=58}} Extreme demands are placed on purity and cleanliness of beryllium to avoid artifacts in the X-ray images. Beryllium is used in X-ray windows because it is transparent to X-rays, allowing for clearer and more efficient imaging.<ref>{{cite web |url=https://www.esrf.fr/home/UsersAndScience/Experiments/StructMaterials/BM05/BeamlineGuide/OpticsHutch/Be_windows.html#:~:text=The%20purpose%20of%20the%20beryllium,small%20way%20by%20passing%20through. |title=Beryllium Windows |website=European Synchrotron Radiation Facility |access-date=Sep 15, 2024 }}</ref> Thin beryllium foils are used as radiation windows for X-ray detectors, and their extremely low absorption minimizes the heating effects caused by high-intensity, low energy X-rays typical of [[synchrotron]] radiation. Vacuum-tight windows and beam-tubes for radiation experiments on synchrotrons are manufactured exclusively from beryllium. In scientific setups for various X-ray emission studies (e.g., [[energy-dispersive X-ray spectroscopy]]) the sample holder is usually made of beryllium because its emitted X-rays have much lower energies (≈100&nbsp;eV) than X-rays from most studied materials.<ref name="Behrens-2003" />

Low [[atomic number]] also makes beryllium relatively transparent to energetic [[Elementary particle|particles]]. Therefore, it is used to build the [[beamline|beam pipe]] around the collision region in [[particle physics]] setups, such as all four main detector experiments at the [[Large Hadron Collider]] ([[A Large Ion Collider Experiment|ALICE]], [[ATLAS experiment|ATLAS]], [[Compact Muon Solenoid|CMS]], [[LHCb]]),<ref>{{cite web |title=Installation and commissioning of vacuum systems for the LHC particle detectors |publisher =CERN |first1 =R. |last1 =Veness |first2 =D. |last2 =Ramos |first3 =P. |last3 =Lepeule |first4 =A. |last4 =Rossi |first5 =G. |last5 =Schneider |first6 =S. |last6 =Blanchard |url =http://accelconf.web.cern.ch/accelconf/PAC2009/papers/mo6rfp010.pdf |access-date =13 January 2012|archive-date =14 November 2011|archive-url =https://web.archive.org/web/20111114063409/http://accelconf.web.cern.ch/accelconf/PAC2009/papers/mo6rfp010.pdf |url-status =live }}</ref> the [[Tevatron]] and at [[SLAC]]. The low density of beryllium allows collision products to reach the surrounding detectors without significant interaction, its stiffness allows a powerful vacuum to be produced within the pipe to minimize interaction with gases, its thermal stability allows it to function correctly at temperatures of only a few degrees above [[absolute zero]], and its [[diamagnetic]] nature keeps it from interfering with the complex multipole magnet systems used to steer and [[strong focusing|focus]] the [[particle beam]]s.<ref>{{cite journal |doi=10.1016/S0168-9002(01)01149-4 |title=A new inner vertex detector for STAR |date=2001 |author=Wieman, H |journal=Nuclear Instruments and Methods in Physics Research Section A |volume=473 |issue=1–2 |page=205 |bibcode=2001NIMPA.473..205W |last2=Bieser |first2=F. |last3=Kleinfelder |first3=S. |last4=Matis |first4=H. S. |last5=Nevski |first5=P. |last6=Rai |first6=G. |last7=Smirnov |first7=N. |s2cid=39909027 |url=https://digital.library.unt.edu/ark:/67531/metadc786424/m2/1/high_res_d/860449.pdf |access-date=30 October 2021 |archive-date=17 October 2020 |archive-url=https://web.archive.org/web/20201017190110/https://digital.library.unt.edu/ark:/67531/metadc786424/m2/1/high_res_d/860449.pdf |url-status=live}}</ref>

=== Mechanical applications ===
Because of its stiffness, light weight and dimensional stability over a wide temperature range, beryllium metal is used for lightweight structural components in the defense and [[aerospace]] industries in high-speed [[aircraft]], [[guided missile]]s, [[spacecraft]], and [[satellite]]s, including the [[James Webb Space Telescope]]. Several [[liquid-fuel rocket]]s have used [[rocket engine nozzle|rocket nozzles]] made of pure beryllium.<ref>{{cite book |chapter-url=https://books.google.com/books?id=IpEnvBtSfPQC&pg=PA690 |title=Metals handbook|chapter=Beryllium |first=Joseph R. |last=Davis |publisher=ASM International |date=1998 |isbn=978-0-87170-654-6 |pages=690–691 |access-date=30 October 2021 |archive-date=27 July 2020 |archive-url=https://web.archive.org/web/20200727094719/https://books.google.com/books?id=IpEnvBtSfPQC&pg=PA690 |url-status=live }}</ref><ref>{{cite book |url=https://books.google.com/books?id=6fdmMuj0rNEC&pg=PA62 |page=62 |title=Encyclopedia of materials, parts, and finishes |author=Schwartz, Mel M. |publisher=CRC Press |date=2002 |isbn=978-1-56676-661-6 |access-date=30 October 2021 |archive-date=27 July 2020 |archive-url=https://web.archive.org/web/20200727094919/https://books.google.com/books?id=6fdmMuj0rNEC&pg=PA62 |url-status=live }}</ref> The high elastic stiffness of beryllium has led to its extensive use in precision instrumentation, e.g. in [[inertial guidance]] systems and in the support mechanisms for optical systems.<ref name="Behrens-2003" /> Beryllium powder was itself studied as a [[rocket fuel]], but this use has never materialized.{{sfn|Emsley|2001|p=58}} A small number of extreme high-end [[bicycle frame]]s have been built with beryllium.<ref name="museum">{{cite web |url=http://mombat.org/American.htm |title=Museum of Mountain Bike Art & Technology: American Bicycle Manufacturing |access-date=26 September 2011 |archive-url=https://web.archive.org/web/20110720022521/http://mombat.org/American.htm |archive-date=20 July 2011 }}</ref> From 1998 to 2000, the [[McLaren]] [[Formula One]] team used [[Mercedes-Benz]] engines with [[beryllium-aluminium alloy|beryllium–aluminium alloy]] pistons.<ref>{{cite web |last=Ward |first=Wayne |title=Aluminium-Beryllium |url=http://www.ret-monitor.com/articles/967/aluminium-beryllium/? |archive-url=https://web.archive.org/web/20100801083918/http://www.ret-monitor.com/articles/967/aluminium-beryllium/ |archive-date=1 August 2010 |publisher=Ret-Monitor |access-date=18 July 2012 }}</ref> The use of beryllium engine components was banned following a protest by [[Scuderia Ferrari]].<ref>{{cite web |last=Collantine |first=Keith |title=Banned! – Beryllium |url=http://www.f1fanatic.co.uk/2007/02/08/banned-beryllium/ |access-date=18 July 2012 |date=8 February 2007 |archive-date=21 July 2012 |archive-url=https://web.archive.org/web/20120721090504/http://www.f1fanatic.co.uk/2007/02/08/banned-beryllium/ |url-status=live }}</ref> An earlier major application of beryllium was in [[brake]]s for military [[airplane]]s because of its hardness, high melting point, and exceptional ability to [[heat dissipation|dissipate heat]]. Environmental considerations have led to substitution by other materials.<ref name="Behrens-2003" />

==== Alloys ====

Mixing about 2.0% beryllium into [[copper]] forms an [[alloy]] called [[beryllium copper]] that is six times stronger than copper alone.<ref name="McGraw-Hill2004">{{cite book |title=Concise Encyclopedia of Chemistry |editor=Geller, Elizabeth |publisher=McGraw-Hill |location=New York City |date=2004 |isbn=978-0-07-143953-4}}</ref> Beryllium alloys are used in many applications because of their combination of elasticity, high [[electrical conductivity]] and [[thermal conductivity]], high strength and [[hardness (materials science)|hardness]], nonmagnetic properties, as well as good [[corrosion]] and [[fatigue (material)|fatigue resistance]].{{sfn|Emsley|2001|p=58}}<ref name="deGruyter" /> These applications include<!-- the making of [[spot welding]] electrodes,--> non-sparking tools that are used near flammable gases ([[beryllium nickel]]), [[spring (device)|springs]], membranes (beryllium nickel and [[beryllium iron]]) used in surgical instruments, and high temperature devices<!-- and [[electrical contact]]s-->.{{sfn|Emsley|2001|p=58}}<ref name="deGruyter" /> As little as 50 parts per million of beryllium alloyed with liquid [[magnesium]] leads to a significant increase in oxidation resistance and decrease in flammability.<ref name="deGruyter" />
[[File:Beryllium Copper Adjustable Wrench.jpg|thumb|Beryllium copper adjustable wrench]]

Beryllium-copper alloys were also applied as a hardening agent in "[[Needlegun scaler|Jason pistols]]", which were used to strip the paint from the hulls of ships.<ref>{{cite news |date=1 February 2005 |access-date=8 August 2009 |url=http://www.smh.com.au/news/National/Defence-forces-face-rare-toxic-metal-exposure-risk/2005/02/01/1107228681666.html |title=Defence forces face rare toxic metal exposure risk|work=The Sydney Morning Herald |archive-date=30 December 2007 |archive-url=https://web.archive.org/web/20071230001424/http://www.smh.com.au/news/National/Defence-forces-face-rare-toxic-metal-exposure-risk/2005/02/01/1107228681666.html |url-status=live }}</ref>

Beryllium–copper alloys are also widely used in modern aerospace and defense applications, particularly in high-performance electrical connectors, battery safety fuses, and microswitches that require a balance of conductivity, corrosion resistance, and fatigue strength.<ref>{{cite web |last=hemanth |date=2025-05-25 |title=Beryllium Applications in Modern Technology: From Aerospace to X-Rays |url=https://minetometal.com/beryllium-uses-in-modern-technology/ |access-date=2025-06-22 |language=en-US }}</ref>

A metal matrix composite material combining beryllium with [[aluminium]] developed under the trade name [[AlBeMet]] for the high performance aerospace industry has low weight but four times the stiffness of aluminum alone.<ref>Parsonage, T. (2000). Beryllium metal matrix composites for aerospace and commercial applications. Materials science and technology, 16(7-8), 732-738.</ref>

=== Mirrors ===
Large-area beryllium [[mirror]]s, frequently with a [[honeycomb mirror|honeycomb support structure]], are used, for example, in [[meteorological satellite]]s where low weight and long-term dimensional stability are critical. Smaller beryllium mirrors are used in [[optical guidance]] systems and in [[fire-control system]]s, e.g. in the German-made [[Leopard 1]] and [[Leopard 2]] [[main battle tank]]s. In these systems, very rapid movement of the mirror is required, which again dictates low mass and high rigidity. Usually the beryllium mirror is coated with hard [[electroless nickel plating]] which can be more easily polished to a finer optical finish than beryllium. In some applications, the beryllium blank is polished without any coating. This is particularly applicable to [[cryogenic]] operation where thermal expansion mismatch can cause the coating to buckle.<ref name="Behrens-2003" />

The [[James Webb Space Telescope]] has 18 hexagonal beryllium sections for its mirrors, each plated with a thin layer of gold.<ref>{{cite web |url=https://www.quantamagazine.org/why-nasas-james-webb-space-telescope-matters-so-much-20211203 |title=The Webb Space Telescope Will Rewrite Cosmic History. If It Works |date=3 December 2021 |access-date=5 December 2021 |publisher=Quanta Magazine |archive-date=5 December 2021 |archive-url=https://web.archive.org/web/20211205004057/https://www.quantamagazine.org/why-nasas-james-webb-space-telescope-matters-so-much-20211203/ |url-status=live }}</ref> Because JWST will face a temperature of 33 K, the mirror is made of gold-plated beryllium, which is capable of handling extreme cold better than glass. Beryllium contracts and deforms less than glass and remains more uniform in such temperatures.<ref>{{cite journal |title=The James Webb Space Telescope |first=Jonathan P. |last=Gardner |date=2007 |journal=Proceedings of Science |volume=52 |url=http://pos.sissa.it/archive/conferences/052/005/MRU_005.pdf |bibcode=2007mru..confE...5G |page=5 |doi=10.22323/1.052.0005 |s2cid=261976160 |access-date=15 January 2009 |archive-date=4 June 2016 |archive-url=https://web.archive.org/web/20160604034944/http://pos.sissa.it/archive/conferences/052/005/MRU_005.pdf |url-status=live |doi-access=free }}</ref> For the same reason, the optics of the [[Spitzer Space Telescope]] are entirely built of beryllium metal.<ref>{{cite journal |title=The Spitzer Space Telescope Mission |arxiv=astro-ph/0406223 |journal=Astrophysical Journal Supplement |date=2004 |doi=10.1086/422992 |volume=154 |issue=1 |pages=1–9 |last1=Werner |first1=M. W. |last2=Roellig |first2=T. L. |last3=Low |first3=F. J. |last4=Rieke |first4=G. H. |last5=Rieke |first5=M. |last6=Hoffmann |first6=W. F. |last7=Young |first7=E. |last8=Houck |first8=J. R. |last9=Brandl |first9=B. |bibcode=2004ApJS..154....1W |s2cid=119379934 |display-authors=8 }}</ref>

=== Magnetic applications ===
[[File:BERYLLIUM - KUGEL 1.JPG|thumb|A hollow beryllium sphere used in a [[gyrocompass]] of the [[Boeing B-52 Stratofortress]] aircraft<ref>[[Theodore Gray|Gray, Theodore]]. [https://periodictable.com/Items/004.7/index.html Gyroscope sphere. An example of the element Beryllium] {{Webarchive|url=https://web.archive.org/web/20210414085028/https://periodictable.com/Items/004.7/index.html |date=14 April 2021 }}. periodictable.com</ref>]]

Beryllium is non-magnetic. Therefore, tools fabricated out of beryllium-based materials are used by naval or military [[explosive ordnance disposal]] teams for work on or near [[naval mine]]s, since these mines commonly have [[fuze|magnetic fuzes]].<ref>{{cite news |url=http://oai.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identifier=AD0263919 |title=The selection of low-magnetic alloys for EOD tools |publisher=Naval Weapons Plant Washington DC |author=Kojola, Kenneth |author2=Lurie, William |date=9 August 1961 |access-date=28 February 2010 |archive-url=https://web.archive.org/web/20110823130608/http://oai.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identifier=AD0263919 |archive-date=23 August 2011 }}</ref> They are also found in maintenance and construction materials near [[magnetic resonance imaging]] (MRI) machines because of the high magnetic fields generated.<ref>{{cite book |url=https://books.google.com/books?id=EqtlqFNkWwQC&pg=PT891 |page=891 |title=Understanding anesthesia equipment |author=Dorsch, Jerry A. |author2=Dorsch, Susan E. |name-list-style=amp |publisher=Lippincott Williams & Wilkins |date=2007 |isbn=978-0-7817-7603-5 |access-date=30 October 2021 |archive-date=27 July 2020 |archive-url=https://web.archive.org/web/20200727101243/https://books.google.com/books?id=EqtlqFNkWwQC&pg=PT891 |url-status=live }}</ref>

=== Nuclear applications ===
High purity beryllium can be used in nuclear reactors as a moderator,<ref>{{citation |last=Sicius |first=Hermann |title=Alkaline Earth Metals: Elements of the Second Main Group |date=2024 |work=Handbook of the Chemical Elements |pages=77–139 |url=https://link.springer.com/10.1007/978-3-662-68921-9_2 |access-date=2025-03-05 |place=Berlin, Heidelberg |publisher=Springer Berlin Heidelberg |language=en |doi=10.1007/978-3-662-68921-9_2 |isbn=978-3-662-68920-2 }}</ref> reflector, or as cladding on fuel elements.<ref>Beeston, J. M. (1971). Beryllium metal as a neutron moderator and reflector material. Nuclear engineering and design, 14(3), 445-474.</ref><ref>A. Tomberlin T. (2004). Beryllium-a unique material in nuclear applications. Idaho Falls, ID: Idaho National Laboratory.</ref>
Thin plates or foils of beryllium are sometimes used in [[nuclear weapon design]]s as the very outer layer of the [[plutonium pit]]s in the primary stages of [[thermonuclear bomb]]s, placed to surround the [[fissile]] material. These layers of beryllium are good "pushers" for the [[implosion (mechanical process)|implosion]] of the [[plutonium-239]], and they are good [[neutron reflector]]s, just as in beryllium-moderated [[nuclear reactors]].<ref name="weapons" />

Beryllium is commonly used in some [[neutron source]]s in laboratory devices in which relatively few neutrons are needed (rather than having to use a nuclear reactor or a [[particle accelerator]]-powered [[neutron generator]]). For this purpose, beryllium-9 is mixed with a source of alpha particles such as [[polonium]]-210, [[radium]]-226, [[plutonium]]-238, or [[americium]]-241.<ref name=NRC-2010/> In the nuclear reaction that occurs, a beryllium nucleus is [[Nuclear transmutation|transmuted]] into carbon-12, and one free neutron is emitted, traveling in about the same direction as the alpha particle was heading. Such [[alpha decay]]-driven beryllium neutron sources, named [[Modulated neutron initiator|"urchin"]] neutron initiators, were used in some early [[atomic bomb]]s.<ref name="weapons">{{cite book |url=https://books.google.com/books?id=yTIOAAAAQAAJ&pg=PA35 |page=35 |title=How nuclear weapons spread |author=Barnaby, Frank |publisher=Routledge |date=1993 |isbn=978-0-415-07674-6 |access-date=30 October 2021 |archive-date=27 July 2020 |archive-url=https://web.archive.org/web/20200727094353/https://books.google.com/books?id=yTIOAAAAQAAJ&pg=PA35 |url-status=live }}</ref> Neutron sources in which beryllium is bombarded with [[gamma ray]]s from a [[gamma decay]] radioisotope are also used to produce laboratory neutrons.<ref name="Byrne-2011">Byrne, J. ''Neutrons, Nuclei, and Matter'', Dover Publications, Mineola, NY, 2011, {{ISBN|0-486-48238-3}}, pp. 32–33.</ref>

[[File:CANDU fuel bundles.jpg|right|thumb|upright=1.6|Two CANDU fuel bundles: Each about 50&nbsp;cm in length and 10&nbsp;cm in diameter. Notice the small appendages on the fuel clad surfaces]]

Beryllium is used in fuel fabrication for [[CANDU]] reactors. The fuel elements have small appendages that are resistance brazed to the fuel cladding using an induction brazing process with Be as the braze filler material. Bearing pads are brazed in place to prevent contact between the fuel bundle and the pressure tube containing it, and inter-element spacer pads are brazed on to prevent element to element contact.<ref>Harmsen, J. G., Lewis, B. J., Pant, A., & Thompson, W. T. (2010, October). Beryllium brazing considerations in CANDU fuel bundle manufacture. In Proceedings of the Eleventh Conference on CANDU Fuel, Niagara Falls, ON (pp. 1-12).</ref>

Beryllium is used at the [[Joint European Torus]] [[nuclear fusion|nuclear-fusion research laboratory]], and it will be used in the more advanced [[ITER]] to condition the components which face the plasma.<ref>{{cite book |url=https://books.google.com/books?id=9ngHTkC8hG8C&pg=PA15 |page=15 |title=Nuclear fusion research |author=Clark, R. E. H. |author2=Reiter, D. |publisher=Springer |date=2005 |isbn=978-3-540-23038-0 |access-date=30 October 2021 |archive-date=27 July 2020 |archive-url=https://web.archive.org/web/20200727091926/https://books.google.com/books?id=9ngHTkC8hG8C&pg=PA15 |url-status=live }}</ref> Beryllium has been proposed as a [[Cladding (nuclear fuel)|cladding]] material for [[nuclear fuel rod]]s, because of its good combination of mechanical, chemical, and nuclear properties.<ref name="Behrens-2003" /> [[Beryllium fluoride]] is one of the constituent salts of the eutectic salt mixture [[FLiBe]], which is used as a solvent, moderator and coolant in many hypothetical [[molten salt reactor]] designs, including the [[liquid fluoride thorium reactor]] (LFTR).<ref>{{cite journal |doi=10.1016/j.fusengdes.2005.08.101 |title=JUPITER-II molten salt Flibe research: An update on tritium, mobilization and redox chemistry experiments |date=2006 |last1=Petti |first1=D. |last2=Smolik |first2=G. |last3=Simpson|first3=M. |last4=Sharpe |first4=J.|last5=Anderl |first5=R.|last6=Fukada |first6=S. |last7=Hatano|first7=Y. |last8=Hara |first8=M. |last9=Oya |first9=Y. |journal=[[Fusion Engineering and Design]] |volume=81 |page=1439 |issue=8–14|bibcode=2006FusED..81.1439P |osti=911741|display-authors=8|url=https://digital.library.unt.edu/ark:/67531/metadc885108/ |access-date=30 October 2021 |archive-date=26 April 2021 |archive-url=https://web.archive.org/web/20210426171553/https://digital.library.unt.edu/ark:/67531/metadc885108/ |url-status=live }}</ref>

=== Acoustics ===
The low weight and high rigidity of beryllium make it useful as a material for high-frequency [[speaker driver]]s. Because beryllium is expensive (many times more than [[titanium]]), hard to shape due to its brittleness, and toxic if mishandled, beryllium [[tweeter]]s are limited to high-end home,<ref>{{cite web |url=http://www.scan-speak.dk/news/20100429a.pdf |archive-url=https://web.archive.org/web/20160303192100/http://www.scan-speak.dk/news/20100429a.pdf |archive-date=3 March 2016 |publisher=Scan Speak|date=May 2010 |title=Scan Speak offers Be tweeters to OEMs and Do-It-Yourselfers }}</ref><ref>{{cite web |url=http://www.hometheaterhifi.com/speakers/232-usher-be-718-bookshelf-speakers-with-beryllium-tweeters.html |archive-url=https://web.archive.org/web/20110613202401/http://www.hometheaterhifi.com/speakers/232-usher-be-718-bookshelf-speakers-with-beryllium-tweeters.html |archive-date=13 June 2011 |first=John E. Jr. |last=Johnson |date=12 November 2007 |access-date=18 September 2008 |title=Usher Be-718 Bookshelf Speakers with Beryllium Tweeters }}</ref><ref>{{cite web |url=http://www.krksys.com/krk-studio-monitor-speakers/expose.html |publisher=KRK Systems |access-date=12 February 2009 |title=Exposé E8B studio monitor |archive-date=10 April 2011 |archive-url=https://web.archive.org/web/20110410205303/http://www.krksys.com/krk-studio-monitor-speakers/expose.html |url-status=live }}</ref> [[pro audio]], and [[public address]] applications.<ref>{{cite web |url=http://www.focalprofessional.com/en/technologies/index.php#tabs-2 |archive-url=https://web.archive.org/web/20121231000340/http://www.focalprofessional.com/en/technologies/index.php#tabs-2 |archive-date=31 December 2012 |title=Beryllium use in pro audio Focal speakers}}</ref><ref>{{cite web |work=VUE Audiotechnik |url=http://www.vueaudio.com/press/ |access-date=21 May 2012 |title=VUE Audio announces use of Be in Pro Audio loudspeakers |archive-url=https://web.archive.org/web/20120510155255/http://www.vueaudio.com/press/ |archive-date=10 May 2012 }}</ref> Some high-fidelity products have been fraudulently claimed to be made of the material.<ref>{{cite web |url=http://www.docstoc.com/docs/45957370/BRUSH-WELLMAN |first=Mark |last=Svilar |date=8 January 2004 |access-date=13 February 2009 |title=Analysis of "Beryllium" Speaker Dome and Cone Obtained from China |archive-url=https://web.archive.org/web/20130517084140/http://www.docstoc.com/docs/45957370/BRUSH-WELLMAN |archive-date=17 May 2013 }}</ref>

Beryllium was used for [[cantilever]]s in high-performance [[Magnetic cartridge|phonograph cartridge]] styli, where its extreme stiffness and low density allowed for tracking weights to be reduced to 1 gram while still tracking high frequency passages with minimal distortion.<ref>{{cite web |url=https://pubs.shure.com/guide/V15VxMR/en-US |title=Shure V15VxMR User's Guide |page=2 |website=[[Shure]] |archive-url=https://web.archive.org/web/20170110184904/http://cdn.shure.com/user_guide/upload/2221/v15vxmr-user-guide-english.pdf |archive-date=10 January 2017}}</ref>

In sound amplification systems, the speed at which sound travels directly affects the resonant frequency of the [[amplifier]], thereby influencing the range of audible high-frequency sounds. Beryllium stands out due to its exceptionally high speed of sound propagation compared to other metals.<ref>{{cite report |title=Reactor Material Specifications |publisher=Oak Ridge National Laboratory |date=1958 |page=227 |url=https://books.google.com/books?id=uSA1xJaSZO4C&dq=Beryllium+sound+propagation+compared+to+other+metals.&pg=PA227 |access-date=July 14, 2024 }}</ref> This unique property allows beryllium to achieve higher resonant frequencies, making it an ideal material for use as a [[Diaphragm (acoustics)|diaphragm]] in high-quality loudspeakers.<ref>{{cite web |url=https://www.refractorymetal.org/6-common-uses-of-beryllium/ |title=6 Common Uses Of Beryllium |website=Refractory Metals |date=28 April 2020 |access-date=July 14, 2024}}</ref>

=== Electronics ===
Beryllium is a [[p-type semiconductor|p-type]] [[dopant]] in [[List of semiconductor materials|III-V compound semiconductors]]. It is widely used in materials such as [[gallium arsenide|GaAs]], [[AlGaAs]], [[InGaAs]] and [[InAlAs]] grown by [[molecular-beam epitaxy]] (MBE).<ref>{{cite book |url=https://books.google.com/books?id=oJs6nK3TZrwC&pg=PA104 |page=104 |title=High-power diode lasers |author=Diehl, Roland |publisher=Springer |date=2000 |isbn=978-3-540-66693-6 |access-date=30 October 2021 |archive-date=27 July 2020 |archive-url=https://web.archive.org/web/20200727094835/https://books.google.com/books?id=oJs6nK3TZrwC&pg=PA104 |url-status=live }}</ref> Cross-rolled beryllium sheet is an excellent structural support for [[printed circuit board]]s in [[surface-mount technology]]. In critical electronic applications, beryllium is both a structural support and [[heat sink]]. The application also requires a coefficient of [[thermal expansion]] that is well matched to the alumina and [[glass-reinforced plastic|polyimide-glass]] [[Substrate (materials science)|substrates]]. The beryllium-beryllium oxide [[metal matrix composite|composite]] "[[E-Material]]s" have been specially designed for these electronic applications and have the additional advantage that the thermal expansion coefficient can be tailored to match diverse substrate materials.<ref name="Behrens-2003" />

[[Beryllium oxide]] is useful for many applications that require the combined properties of an [[electrical insulator]] and an excellent heat conductor, with high strength and hardness and a very high melting point. Beryllium oxide is frequently used as an insulator base plate in [[power semiconductor device|high-power]] [[transistor]]s in [[radio frequency]] [[transmitter]]s for telecommunications. Beryllium oxide is being studied for use in increasing the [[thermal conductivity]] of [[uranium dioxide]] [[nuclear fuel]] pellets.<ref>{{cite web |url=http://www.purdue.edu/uns/html4ever/2005/050927.Solomon.nuclear.html |date=27 September 2005 |title=Purdue engineers create safer, more efficient nuclear fuel, model its performance |publisher=Purdue University |access-date=18 September 2008 |archive-date=27 May 2012 |archive-url=https://web.archive.org/web/20120527141643/http://www.purdue.edu/uns/html4ever/2005/050927.Solomon.nuclear.html |url-status=live }}</ref> Beryllium compounds were used in [[fluorescent light]]ing tubes, but this use was discontinued because of the disease [[berylliosis]] which developed in the workers who were making the tubes.<ref>{{cite book |pages=30–33 |author=Breslin AJ |chapter=Ch. 3. Exposures and Patterns of Disease in the Beryllium Industry |isbn=978-0-12-671850-8 |title=Beryllium: Its Industrial Hygiene Aspects |editor=Stokinger, HE |publisher=Academic Press, New York |date=1966 }}</ref>

=== Medical applications ===
Beryllium is a component of several [[Dental material|dental alloys]].<ref>OSHA Hazard Information Bulletin HIB 02-04-19 (rev. 05-14-02) [https://web.archive.org/web/20161012071826/https://www.osha.gov/dts/hib/hib_data/hib20020419.html Preventing Adverse Health Effects From Exposure to Beryllium in Dental Laboratories]</ref><ref name="ElshahawyWatanabe2014">{{cite journal |last1=Elshahawy |first1=W. |last2=Watanabe |first2=I. |title=Biocompatibility of dental alloys used in dental fixed prosthodontics |journal=Tanta Dental Journal |volume=11 |issue=2 |year=2014 |pages=150–159 |doi=10.1016/j.tdj.2014.07.005 |doi-access=free }}</ref> In addition to standard X-ray equipment mentioned in {{slink|Beryllium#Radiation_windows}}, in medical imaging equipment, such as CT scanners and mammography machines, beryllium's strength and light weight enhance durability and performance.<ref>{{cite journal |last1=Zheng |first1=Li |last2=Wang |first2=Xiao |year=2020 |title=Progress in the Application of Rare Light Metal Beryllium |journal=Materials Science Forum |volume=977 |pages=261–271 |doi=10.4028/www.scientific.net/MSF.977.261}}</ref> Beryllium is used in analytical equipment for blood, HIV, and other diseases.<ref>{{cite web |url=https://www.refractorymetal.org/beryllium-foil/ |title=Beryllium Foil |website=Refractory Metals |access-date=Sep 15, 2024}}</ref> Beryllium alloys are used in surgical instruments, optical mirrors, and laser systems for medical treatments.<ref>{{cite book |last=Minnath |first=Mehar |year=2018 |title=Fundamental Biomaterials: Metals |publisher=Woodhead Publishing |editor-last=Balakrishnan |editor-first=Preetha |edition=1st |isbn=978-0-08-102205-4 |chapter=7 - Metals and alloys for biomedical applications |pages=167–174 |doi=10.1016/B978-0-08-102205-4.00007-6}}</ref><ref>{{cite journal |last=Maksimov |first=O. |year=2005 |title=Berryllium chalogenide alloys for visible light emitting and laser diode |journal=Rev.Adv.Mater.Sc |volume=9 |pages=178–183 |url=https://www.ipme.ru/e-journals/RAMS/no_2905/maksimov.pdf |access-date=Sep 15, 2024}}</ref>

== Toxicity and safety ==
{{Main|Acute beryllium poisoning|Berylliosis}}
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=== Biological effects ===
Approximately 35&nbsp;micrograms of beryllium is found in the average human body, an amount not considered harmful.{{sfn|Emsley|2001|p=57}} Beryllium is chemically similar to [[magnesium]] and therefore can displace it from [[enzyme]]s, which causes them to malfunction.{{sfn|Emsley|2001|p=57}} Because Be<sup>2+</sup> is a highly charged and small ion, it can easily get into many tissues and cells, where it specifically targets cell nuclei, inhibiting many enzymes, including those used for synthesizing DNA. Its toxicity is exacerbated by the fact that the body has no means to control beryllium levels, and once inside the body, beryllium cannot be removed.<ref name="Venugopal">{{cite book |last=Venugopal |first=B. |date=14 March 2013 |title=Physiologic and Chemical Basis for Metal Toxicity |publisher=Springer |pages=167–8 |isbn=978-1-4684-2952-7}}</ref>

=== Inhalation ===
Chronic beryllium disease (CBD), or [[berylliosis]], is a [[pulmonary]] and [[systemic circulation|systemic]] [[granuloma]]tous disease caused by inhalation of dust or fumes contaminated with beryllium; either large amounts over a short time or small amounts over a long time can lead to this ailment. Symptoms of the disease can take up to five years to develop; about a third of patients with it die and the survivors are left disabled.{{sfn|Emsley|2001|p=57}} The [[International Agency for Research on Cancer]] (IARC) lists beryllium and beryllium compounds as [[List of IARC Group 1 carcinogens|Category 1 carcinogens]].<ref>{{cite book |chapter=Beryllium and Beryllium Compounds |chapter-url=http://www.inchem.org/documents/iarc/vol58/mono58-1.html |publisher=International Agency for Research on Cancer |title=IARC Monograph |volume=58 |date=1993 |access-date=18 September 2008 |archive-date=26 May 2024 |archive-url=https://archive.today/20240526025522/https://www.webcitation.org/69YsDBNKb?url=http://www.inchem.org/documents/iarc/vol58/mono58-1.html |url-status=live }}</ref>

=== Occupational exposure ===
In the US, the [[Occupational Safety and Health Administration]] (OSHA) has designated a [[permissible exposure limit]] (PEL) for beryllium and beryllium compounds of 0.2&nbsp;μg/m<sup>3</sup> as an 8-hour time-weighted average (TWA) and 2.0&nbsp;μg/m<sup>3</sup> as a [[short-term exposure limit]] over a sampling period of 15 minutes. The [[National Institute for Occupational Safety and Health]] (NIOSH) has set a [[recommended exposure limit]] (REL) upper-bound threshold of 0.5&nbsp;μg/m<sup>3</sup>. The [[IDLH]] (immediately dangerous to life and health) value is 4&nbsp;mg/m<sup>3</sup>.<ref>{{PGCH|0054}}</ref> The toxicity of beryllium is on par with other toxic metalloids/metals, such as [[arsenic]] and [[mercury (element)|mercury]].<ref>{{cite web |url=https://www.cdc.gov/niosh/npg/npgd0038.html |title=CDC - NIOSH Pocket Guide to Chemical Hazards - Arsenic (inorganic compounds, as As)<!-- Bot generated title --> |access-date=30 October 2021 |archive-date=11 May 2017 |archive-url=https://web.archive.org/web/20170511073321/https://www.cdc.gov/niosh/npg/npgd0038.html |url-status=live }}</ref><ref>[https://www.cdc.gov/niosh/npg/npgd0383.html NIOSH Pocket Guide to Chemical Hazards - Mercury compounds]. The National Institute for Occupational Safety and Health (NIOSH). {{webarchive |url=https://web.archive.org/web/20210507085512/https://www.cdc.gov/niosh/npg/npgd0383.html |date=7 May 2021 }}</ref>

Exposure to beryllium in the workplace can lead to a sensitized immune response, and over time development of [[berylliosis]].<ref name="cdc.gov">{{cite web |url=https://www.cdc.gov/niosh/topics/beryllium/be-sensitization-drds.html |title=CDC – Beryllium Research- NIOSH Workplace Safety and Health Topic |website=www.cdc.gov |access-date=30 January 2017 |archive-date=8 March 2013 |archive-url=https://archive.today/20130308164753/http://www.cdc.gov/niosh/topics/beryllium/be-sensitization-drds.html |url-status=live}}</ref> NIOSH in the United States researches these effects in collaboration with a major manufacturer of beryllium products. NIOSH also conducts genetic research on sensitization and CBD, independently of this collaboration.<ref name="cdc.gov" />

Acute beryllium disease in the form of [[chemical pneumonitis]] was first reported in Europe in 1933 and in the United States in 1943. A survey found that about 5% of workers in plants manufacturing [[fluorescent lamp]]s in 1949 in the United States had beryllium-related lung diseases.{{sfn|Emsley|2001|p=5}} Chronic berylliosis resembles [[sarcoidosis]] in many respects, and the [[differential diagnosis]] is often difficult. It killed some early workers in nuclear weapons design, such as [[Herbert L. Anderson]].<ref>{{cite web |url=http://www.atomicarchive.com/Photos/CP1/image5.shtml |title=Photograph of Chicago Pile One Scientists 1946 |date=19 June 2006 |publisher=Office of Public Affairs, Argonne National Laboratory |access-date=18 September 2008 |archive-date=11 December 2008 |archive-url=https://web.archive.org/web/20081211195616/http://www.atomicarchive.com/Photos/CP1/image5.shtml |url-status=live}}</ref>

Beryllium may be found in coal slag. When the slag is formulated into an abrasive agent for blasting paint and rust from hard surfaces, the beryllium can become airborne and become a source of exposure.<ref name="shapiro">[https://www.dailypress.com/2013/08/31/newport-news-shipbuilding-workers-face-a-hidden-toxin/ Newport News Shipbuilding Workers Face a Hidden Toxin], [[Daily Press (Virginia)]], Michael Welles Shapiro, 31 August 2013</ref>

Although the use of beryllium compounds in fluorescent lighting tubes was discontinued in 1949, potential for exposure to beryllium exists in the nuclear and aerospace industries, in the refining of beryllium metal and the melting of beryllium-containing alloys, in the manufacturing of electronic devices, and in the handling of other beryllium-containing material.<ref>{{cite web |url=http://www.inchem.org/documents/ehc/ehc/ehc106.htm |title=Beryllium: ENVIRONMENTAL HEALTH CRITERIA 106 |author=International Programme on Chemical Safety |date=1990 |publisher=World Health Organization |access-date=10 April 2011 |archive-date=9 June 2011 |archive-url=https://web.archive.org/web/20110609023121/http://www.inchem.org/documents/ehc/ehc/ehc106.htm |url-status=live }}</ref>

=== Detection ===
Early researchers undertook the highly hazardous practice of identifying beryllium and its various compounds from its sweet taste. A modern test for beryllium in air and on surfaces has been developed and published as an international voluntary consensus standard, ASTM D7202. The procedure uses dilute [[ammonium bifluoride]] for dissolution and fluorescence detection with beryllium bound to sulfonated hydroxybenzoquinoline, allowing up to 100 times more sensitive detection than the recommended limit for beryllium concentration in the workplace. Fluorescence increases with increasing beryllium concentration. The new procedure has been successfully tested on a variety of surfaces and is effective for the dissolution and detection of refractory beryllium oxide and siliceous beryllium in minute concentrations (ASTM D7458).<ref>{{cite web |url=http://www.astm.org/Standards/D7458.htm |title=ASTM D7458&nbsp;–08 |access-date=8 August 2009 |publisher=American Society for Testing and Materials |archive-date=12 July 2010 |archive-url=https://web.archive.org/web/20100712085740/http://www.astm.org/Standards/D7458.htm |url-status=live }}</ref><ref>{{cite journal |doi=10.1520/JAI13168 |title=Development of a New Fluorescence Method for the Detection of Beryllium on Surfaces |date=2005 |last1=Minogue |first1 =E. M. |last2=Ehler |first2=D. S. |last3=Burrell |first3=A. K. |last4= McCleskey |first4=T. M. |last5=Taylor |first5=T. P. |journal=Journal of ASTM International |volume=2 |article-number=13168 |issue=9 }}</ref> The NIOSH Manual of Analytical Methods contains methods for measuring occupational exposures to beryllium.<ref>{{cite web |url=https://www.cdc.gov/niosh/nmam/method-b.html |title=CDC – NIOSH Publications and Products – NIOSH Manual of Analytical Methods (2003–154) – Alpha List B |website=www.cdc.gov |access-date=30 January 2017 |archive-date=16 December 2016 |archive-url=https://web.archive.org/web/20161216223432/https://www.cdc.gov/niosh/nmam/method-b.html |url-status=live }}</ref>

== Notes ==
{{notelist}}
{{reflist|group=n}}

== References ==
{{reflist|30em}}

== Cited sources ==
* <!-- Ems -->{{cite book
 | title=Nature's Building Blocks: An A–Z Guide to the Elements
 | url=https://archive.org/details/naturesbuildingb0000emsl
 | url-access=registration
 | last=Emsley | first=John
 | publisher=Oxford University Press
 | year=2001
 | location=Oxford, England, UK
 | isbn=978-0-19-850340-8
 }}
* <!-- We -->{{cite book
 | last=Weeks | first=Mary Elvira | author-link=Mary Elvira Weeks
 | author2=Leichester, Henry M.
 | year=1968
 | title=Discovery of the Elements
 | url=https://archive.org/details/discoveryoftheel002045mbp
 | url-access=registration
 | publisher=Journal of Chemical Education
 | location=Easton, PA
 | id=LCCCN 68-15217
 | ref=CITEREFWeeks1968
 }}

== Further reading ==
* {{cite journal |author=Newman LS|date=2003|title=Beryllium|journal=Chemical & Engineering News|volume=81|page=38|doi=10.1021/cen-v081n036.p038|issue=36}}
* Mroz MM, Balkissoon R, and Newman LS. "Beryllium". In: Bingham E, Cohrssen B, Powell C (eds.) ''Patty's Toxicology'', Fifth Edition. New York: John Wiley & Sons 2001, 177–220.
* Walsh, KA, [https://books.google.com/books?id=3-GbhmSfyeYC ''Beryllium Chemistry and Processing'']. Vidal, EE. et al. Eds. 2009, Materials Park, OH:ASM International.
* [https://web.archive.org/web/20190207015758/http://www.bjorklundnutrition.net/2011/11/belpt/ Beryllium Lymphocyte Proliferation Testing (BeLPT).] DOE Specification 1142–2001. Washington, DC: U.S. Department of Energy, 2001.

== External links ==
{{sister project links |wikt=Beryllium |auto=1}}
* [https://www.atsdr.cdc.gov/csem/csem.html ATSDR Case Studies in Environmental Medicine: Beryllium Toxicity] {{webarchive|url=https://web.archive.org/web/20160204174821/http://www.atsdr.cdc.gov/csem/csem.asp?csem=7&po=7 |date=4 February 2016 }} U.S. [[Department of Health and Human Services]]
* [http://education.jlab.org/itselemental/ele004.html It's Elemental&nbsp;– Beryllium] {{Webarchive|url=https://web.archive.org/web/20160604035053/http://education.jlab.org/itselemental/ele004.html |date=4 June 2016 }}
* [[MSDS]]: [https://web.archive.org/web/20070928003708/http://espi-metals.com/msds%27s/beryllium.pdf ESPI Metals]
* [http://www.periodicvideos.com/videos/004.htm Beryllium] at ''[[The Periodic Table of Videos]]'' (University of Nottingham)
* [https://www.cdc.gov/niosh/topics/beryllium/ National Institute for Occupational Safety and Health&nbsp;– Beryllium Page]
* [http://www.orau.org/nssp/ National Supplemental Screening Program (Oak Ridge Associated Universities)]
* [https://minerals.usgs.gov/minerals/pubs/commodity/beryllium/100798.pdf Historic Price of Beryllium in USA] {{Webarchive|url=https://web.archive.org/web/20160303222240/http://minerals.usgs.gov/minerals/pubs/commodity/beryllium/100798.pdf |date=3 March 2016 }}
* [[usgs.gov]] (Mineral Commodity Summaries 2025): [https://pubs.usgs.gov/periodicals/mcs2025/mcs2025.pdf#page=44 Beryllium] 

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[[Category:Beryllium| ]]
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