View source for Magnesium

{{About|the chemical element|the use of magnesium as a medication|Magnesium (medical use)}}
{{Distinguish|text=[[manganese]] ''(Mn)''}}
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{{Use dmy dates|date=December 2023}}
{{Infobox magnesium}}
'''Magnesium''' is a [[chemical element]]; it has [[Symbol (chemistry)|symbol]] '''Mg''' and [[atomic number]] 12. It is a shiny gray metal having a low density, low melting point and high chemical reactivity. Like the other [[alkaline earth metal]]s (group 2 of the [[periodic table]]), it occurs naturally only in combination with other elements and almost always has an [[oxidation state]] of +2. It reacts readily with air to form a thin [[Passivation (chemistry)|passivation]] coating of [[magnesium oxide]] that inhibits further corrosion of the metal. The free metal burns with a brilliant-white light. The metal is obtained mainly by [[electrolysis]] of magnesium [[Salt (chemistry)|salts]] obtained from [[brine]]. It is less dense than [[aluminium]] and is used primarily as a component in strong and lightweight [[magnesium alloy|alloys]] that contain aluminium.

In the [[cosmos]], magnesium is produced in large, aging [[star]]s by the sequential addition of three [[Helium nucleus|helium nuclei]] to a [[carbon]] nucleus. When such stars explode as [[supernova]]s, much of the magnesium is expelled into the [[interstellar medium]] where it may recycle into new star systems. Magnesium is the eighth most abundant element in the [[Earth's crust]]<ref name="Abundance" /> and the fourth most common element in the Earth (after [[iron]], [[oxygen]] and [[silicon]]), making up 13% of the planet's mass and a large fraction of the planet's [[Mantle (geology)|mantle]]. It is the third most abundant element dissolved in seawater, after [[sodium]] and [[chlorine]].<ref>{{cite news |url=http://www.seafriends.org.nz/oceano/seawater.htm#composition |title=The chemical composition of seawater |author=Anthoni, J. Floor |date=2006 |website=Seafriends}}</ref>

This element is the eleventh most abundant element by mass in the [[human body]] and is essential to all cells and some 300 [[enzymes]].<ref name="nih" /> Magnesium ions interact with [[polyphosphate]] compounds such as [[Adenosine triphosphate|ATP]], [[DNA]], and [[RNA]]. Hundreds of enzymes require magnesium ions to function. Magnesium compounds are used medicinally as common [[laxatives]] and [[antacids]] (such as [[milk of magnesia]]), and to stabilize abnormal nerve excitation or blood vessel spasm in such conditions as [[eclampsia]].<ref name="nih" />
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== Characteristics ==
=== Physical properties ===
Elemental magnesium is a gray-white lightweight metal, two-thirds the density of aluminium. Magnesium has the lowest melting ({{convert|923|K|°C}}) and the lowest boiling point ({{convert|1363|K|°C}}) of all the alkaline earth metals.<ref>{{Cite web |title=alkaline-earth metal – Physical and chemical behaviour |url=https://www.britannica.com/science/alkaline-earth-metal/Physical-and-chemical-behaviour |access-date=27 March 2022 |website=Encyclopædia Britannica |language=en}}</ref>

Pure polycrystalline magnesium is brittle and easily fractures along [[shear band]]s. It becomes much more [[ductility|malleable]] when alloyed with small amounts of other metals, such as 1% aluminium.<ref>{{cite journal |doi=10.1038/s41598-017-10384-0 |pmid=28874798 |pmc=5585333 |title=A rare-earth free magnesium alloy with improved intrinsic ductility |journal=Scientific Reports |volume=7 |issue=1 |pages=10458 |year=2017 |last1=Sandlöbes |first1=S. |last2=Friák |first2=M. |last3=Korte-Kerzel |first3=S. |last4=Pei |first4=Z. |last5=Neugebauer |first5=J. |last6=Raabe |first6=D. |bibcode=2017NatSR...710458S}}</ref> The malleability of polycrystalline magnesium can also be significantly improved by reducing its grain size to about 1&nbsp;[[micrometre|μm]] or less.<ref>{{cite journal |doi=10.1038/s41467-017-01330-9 |pmid=29042555 |pmc=5715137 |title=Super-formable pure magnesium at room temperature |journal=Nature Communications |volume=8 |issue=1 |pages=972 |year=2017 |last1=Zeng |first1=Zhuoran |last2=Nie |first2=Jian-Feng |last3=Xu |first3=Shi-Wei |last4=Davies |first4=Chris H. J. |last5=Birbilis |first5=Nick |bibcode=2017NatCo...8..972Z}}</ref>

=== Chemical properties ===
====Oxidation====
Magnesium is widely used as a [[reducing agent]].<ref name=":3">{{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=2025-10-10 |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> Although it oxidises in air, it does not need an [[inert atmosphere]] for storage; it forms a thin layer of [[magnesium oxide]] that protects the rest of the metal.<ref name=":0">{{Cite web |last=MMTA |title=Magnesium |url=https://mmta.co.uk/metals/mg/ |access-date=8 November 2023 |website=MMTA |language=en-US}}</ref>

Direct reaction of magnesium with air or oxygen at ambient pressure forms only the "normal" oxide MgO. However, this oxide may be combined with hydrogen peroxide to form [[magnesium peroxide]], MgO<sub>2</sub>, and at low temperature the peroxide may be further reacted with ozone to form magnesium superoxide Mg(O<sub>2</sub>)<sub>2</sub>.<ref>{{cite journal |last1=Vol'nov |first1=I. I. |last2=Tokareva |first2=S. A. |last3=Belevskii |first3=V. N. |last4=Latysheva |first4=E. I. |title=The formation of magnesium perperoxide Mg(O2)2 in the reaction of magnesium peroxide with ozone |journal=Bulletin of the Academy of Sciences of the USSR Division of Chemical Science |date=March 1970 |volume=19 |issue=3 |pages=468–471 |doi=10.1007/bf00848959 }}</ref>

Magnesium reacts with nitrogen in the solid state if it is powdered and heated to just below the melting point, forming [[magnesium nitride]] Mg<sub>3</sub>N<sub>2</sub>.<ref>{{Cite journal|last1=Zong|first1=Fujian|last2=Meng|first2=Chunzhan|last3=Guo|first3=Zhiming|last4=Ji|first4=Feng|last5=Xiao|first5=Hongdi|last6=Zhang|first6=Xijian|last7=Ma|first7=Jin|last8=Ma|first8=Honglei|title=Synthesis and characterization of magnesium nitride powder formed by Mg direct reaction with N2|journal=_Journal of Alloys and Compounds|year=2010 |volume=508|issue=1|pages=172–176|doi=10.1016/j.jallcom.2010.07.224}}</ref>

Magnesium reacts with water at room temperature, though it reacts much more slowly than calcium, a similar group 2 metal.<ref name=":0" /> When submerged in water, [[hydrogen]] bubbles form slowly on the surface of the metal; this reaction happens much more rapidly with powdered magnesium.<ref name=":0" /> The reaction also occurs faster with higher temperatures (see {{slink|#Safety precautions}}). Magnesium's reversible reaction with water can be harnessed to store energy and run a [[Magnesium injection cycle|magnesium-based engine]]. Magnesium also reacts exothermically with most acids such as [[hydrochloric acid]] (HCl), producing [[magnesium chloride]] and hydrogen gas, similar to the HCl reaction with aluminium, zinc, and many other metals.<ref>{{Cite web |title=The rate of reaction of magnesium with hydrochloric acid |url=https://edu.rsc.org/experiments/the-rate-of-reaction-of-magnesium-with-hydrochloric-acid/1916.article |access-date=8 November 2023 |website=RSC Education |language=en}}</ref> Although it is difficult to ignite in mass or bulk, magnesium metal will ignite.

Magnesium may also be used as an igniter for [[thermite]], a mixture of aluminium and iron oxide powder that ignites only at a very high temperature.

==== Reaction with water ====
When finely powdered, magnesium reacts with water to produce magnesium hydroxide and hydrogen gas:
: Mg(s) + 2 H<sub>2</sub>O(l) → Mg(OH)<sub>2</sub>(aq) + H<sub>2</sub>(g)
However, this reaction is much less dramatic than the reactions of the alkali metals with water, because the magnesium hydroxide builds up on the surface of the magnesium metal and inhibits further reaction.<ref name=":4">{{Cite web |date=3 October 2013 |title=Reactions of Group 2 Elements with Water |url=https://chem.libretexts.org/Bookshelves/Inorganic_Chemistry/Supplemental_Modules_and_Websites_(Inorganic_Chemistry)/Descriptive_Chemistry/Elements_Organized_by_Block/1_s-Block_Elements/Group__2_Elements%3A_The_Alkaline_Earth_Metals/1Group_2%3A_Chemical_Reactions_of_Alkali_Earth_Metals/Reactions_of_Group_2_Elements_with_Water |access-date=27 March 2022 |website=Chemistry LibreTexts |language=en}}</ref>

In addition, when reacting with steam it produces magnesium oxide and hydrogen:<ref name=":4" />

Mg(s) + H<sub>2</sub>O(g) → MgO(aq) + H<sub>2</sub>(g)

====Organic chemistry====
{{Further|Grignard reagent}}
Organomagnesium compounds are widespread in [[organic chemistry]]. They are commonly found as [[Grignard reagents]], formed by reaction of magnesium with [[haloalkane]]s or [[Aryl halide|aryl halides]] in [[diethyl ether]].<ref name=":3" /> Examples of Grignard reagents are [[phenylmagnesium bromide]] and [[ethylmagnesium bromide]]. The Grignard reagents function as a common [[nucleophile]], attacking the [[electrophilic]] group such as the carbon atom that is present within the polar bond of a [[carbonyl]] group.

A prominent organomagnesium reagent beyond Grignard reagents is [[magnesium anthracene]] or magnesocene, which is used as a source of highly active magnesium. First prepared in 1954 by independent groups, one led by [[Ernst Otto Fischer]], the other by Albert Wilkinson, magnesocene is a white to off-yellow [[Pyrophoricity|pyrophoric]] powder that violently [[Hydrolysis|hydrolyses]] in water.<ref name=":3" /> The related [[butadiene]]-magnesium adduct serves as a source for the butadiene dianion.

Complexes of dimagnesium(I) have been observed.<ref>{{cite journal |last1=Rösch |first1=B. |last2=Gentner |first2=T. X. |last3=Eyselein |first3=J. |last4=Langer |first4=J. |last5=Elsen |first5=H. |last6=Harder |first6=S. |title=Strongly reducing magnesium(0) complexes |journal=Nature |date=29 April 2021 |volume=592 |issue=7856 |pages=717–721 |doi=10.1038/s41586-021-03401-w |pmid=33911274 |bibcode=2021Natur.592..717R |s2cid=233447380 }}</ref>

==== Detection in solution ====

The presence of magnesium ions can be detected by the addition of [[ammonium chloride]], [[ammonium hydroxide]] and [[monosodium phosphate]] to an aqueous or dilute HCl solution of the salt. The formation of a white precipitate indicates the presence of magnesium ions.

[[Azo violet]] dye can also be used, turning deep blue in the presence of an alkaline solution of magnesium salt. The color is due to the [[adsorption]] of azo violet by [[magnesium hydroxide|Mg(OH)<sub>2</sub>]].

== Forms ==
=== Alloys ===
{{Main|Magnesium alloy}}

[[File:Cold rolling of Mg and Mg-1Al-0.1Ca.jpg|thumb|upright=1.4|Magnesium is brittle, and fractures along [[shear band]]s when its thickness is reduced by only 10% by [[cold rolling]] (top). However, after alloying Mg with 1% Al and 0.1% Ca, its thickness could be reduced by 54% using the same process (bottom).]]
As of 2013, consumption of magnesium alloys was less than one million tonnes per year, compared with 50 million tonnes of [[aluminium alloy]]s. Their use has been historically limited by the tendency of Mg alloys to corrode,<ref name="makar13">{{cite journal |doi=10.1179/imr.1993.38.3.138|title=Corrosion of magnesium|year=1993|last1=Makar|first1=G. L.|last2=Kruger|first2=J.|journal=International Materials Reviews|volume=38|issue=3|pages=138–153|bibcode=1993IMRv...38..138M }}</ref> [[Creep (deformation)|creep]] at high temperatures, and combust.<ref name="giz" />

====Corrosion====
In magnesium alloys, the presence of [[iron]], [[nickel]], [[copper]], or [[cobalt]] strongly activates [[corrosion]]. In more than trace amounts, these metals precipitate as [[intermetallic compound]]s, and the precipitate locales function as active [[cathode|cathodic]] sites that reduce water, causing the loss of magnesium.<ref name="giz" /> Controlling the quantity of these metals improves corrosion resistance. Sufficient [[manganese]] overcomes the corrosive effects of iron. This requires precise control over composition, increasing costs.<ref name="giz" /> Adding a cathodic poison captures atomic hydrogen within the structure of a metal. This prevents the formation of free hydrogen gas, an essential factor of corrosive chemical processes. The addition of about one in three hundred parts [[arsenic]] reduces the corrosion rate of magnesium in a salt solution by a factor of nearly ten.<ref name="giz">{{cite web|url=http://www.gizmag.com/stainless-magnesium-corrosion-monash/28856 |title=Stainless magnesium breakthrough bodes well for manufacturing industries |publisher=Gizmag.com |date=29 August 2013|author=Dodson, Brian |access-date=29 August 2013}}</ref><ref>{{Cite journal | last1 = Birbilis | first1 = N. | last2 = Williams | first2 = G. | last3 = Gusieva | first3 = K. | last4 = Samaniego | first4 = A. | last5 = Gibson | first5 = M. A. | last6 = McMurray | first6 = H. N. | doi = 10.1016/j.elecom.2013.07.021 | title = Poisoning the corrosion of magnesium | journal = Electrochemistry Communications | volume = 34 | pages = 295–298 | year = 2013 }}</ref>

====High-temperature creep and flammability====
Magnesium's tendency to [[Creep (deformation)|creep]] (gradually deform) at high temperatures is greatly reduced by alloying with [[zinc]] and [[rare-earth elements]].<ref>{{cite journal |last1=Choudhuri |first1=Deep |last2=Srinivasan |first2=Srivilliputhur G. |last3=Gibson |first3=Mark A. |last4=Zheng |first4=Yufeng |last5=Jaeger |first5=David L. |last6=Fraser |first6=Hamish L. |last7=Banerjee |first7=Rajarshi |title=Exceptional increase in the creep life of magnesium rare-earth alloys due to localized bond stiffening |journal=Nature Communications |date=8 December 2017 |volume=8 |issue=1 |page=2000 |doi=10.1038/s41467-017-02112-z |pmid=29222427 |pmc=5722870 |bibcode=2017NatCo...8.2000C }}</ref> Flammability is significantly reduced by a small amount of [[calcium]] in the alloy.<ref name="giz" /> By using rare-earth elements, it may be possible to manufacture magnesium alloys that are able to not catch fire at higher temperatures compared to magnesium's [[liquidus]] and in some cases potentially pushing it close to magnesium's boiling point.<ref>{{cite journal |last1=Czerwinski |first1=Frank |title=Controlling the ignition and flammability of magnesium for aerospace applications |journal=Corrosion Science |date=September 2014 |volume=86 |pages=1–16 |doi=10.1016/j.corsci.2014.04.047 |bibcode=2014Corro..86....1C }}</ref>

=== Compounds ===
{{Main|Magnesium compounds}}

Magnesium forms a variety of compounds important to industry and biology, including [[magnesium carbonate]], [[magnesium chloride]], [[magnesium citrate]], [[magnesium hydroxide]] (milk of magnesia), [[magnesium oxide]], [[magnesium sulfate]], and magnesium sulfate heptahydrate ([[Epsom salts]]).<ref>{{Cite web |date=23 March 2021 |title=8 Types of magnesium and their benefits |url=https://www.medicalnewstoday.com/articles/types-of-magnesium |access-date=4 May 2024 |website=www.medicalnewstoday.com |language=en}}</ref><ref>{{Cite web |date=2 October 2013 |title=Chemistry of Magnesium (Z=12) |url=https://chem.libretexts.org/Bookshelves/Inorganic_Chemistry/Supplemental_Modules_and_Websites_(Inorganic_Chemistry)/Descriptive_Chemistry/Elements_Organized_by_Block/1_s-Block_Elements/Group__2_Elements%3A_The_Alkaline_Earth_Metals/Z012_Chemistry_of_Magnesium_(Z12) |access-date=4 May 2024 |website=Chemistry LibreTexts |language=en}}</ref>

As recently as 2020, [[magnesium hydride]] was under investigation as a way to store hydrogen.<ref name=ren14>{{cite journal |last1=Ren |first1=Chai |last2=Fang |first2=Z. Zak |last3=Zhou |first3=Chengshang |last4=Lu |first4=Jun |last5=Ren |first5=Yang |last6=Zhang |first6=Xiaoyi |title=Hydrogen Storage Properties of Magnesium Hydride with V-Based Additives |journal=The Journal of Physical Chemistry C |date=25 September 2014 |volume=118 |issue=38 |pages=21778–21784 |doi=10.1021/jp504766b }}</ref><ref name=baran20>{{cite journal |last1=Baran |first1=Agata |last2=Polański |first2=Marek |title=Magnesium-Based Materials for Hydrogen Storage—A Scope Review |journal=Materials |date=9 September 2020 |volume=13 |issue=18 |pages=3993 |doi=10.3390/ma13183993 |doi-access=free |pmid=32916910 |pmc=7559164 |bibcode=2020Mate...13.3993B }}</ref>

=== Isotopes ===
{{Main|Isotopes of magnesium}}

Magnesium has three stable [[isotope]]s: {{chem|24|Mg}}, {{chem|25|Mg}} and {{chem|26|Mg}}. All are present in significant amounts in nature (see table of isotopes above). About 79% of Mg is {{chem|24|Mg}}. The isotope {{chem|28|Mg}} is radioactive and in the 1950s to 1970s was produced by several nuclear power plants for use in scientific experiments. This isotope has a relatively short half-life (21 hours) and its use was limited by shipping times.

The nuclide {{chem|26|Mg}} has found application in [[isotope|isotopic]] [[geology]], similar to that of aluminium. {{chem|26|Mg}} is a [[radiogenic]] daughter product of [[aluminium-26|{{chem|26|Al}}]], which has a [[half-life]] of 717,000 years. Excessive quantities of stable {{chem|26|Mg}} have been observed in the [[Ca-Al-rich inclusions]] of some [[carbonaceous chondrite]] [[meteorite]]s. This anomalous abundance is attributed to the decay of its parent {{chem|26|Al}} in the inclusions, and researchers conclude that such meteorites were formed in the [[solar nebula]] before the {{chem|26|Al}} had decayed. These are among the oldest objects in the [[Solar System]] and contain preserved information about its early history.

It is conventional to plot {{chem|26|Mg}}/{{chem|24|Mg}} against an Al/Mg ratio. In an [[isochron dating]] plot, the Al/Mg ratio plotted is {{chem|27|Al}}/{{chem|24|Mg}}. The slope of the isochron has no age significance, but indicates the initial {{chem|26|Al}}/{{chem|27|Al}} ratio in the sample at the time when the systems were separated from a common reservoir.

== Production ==
{{See also|Magnesium production by country}}
[[File:Mg sheets and ingots.jpg|thumb|Magnesium sheets and ingots]]

=== Occurrence ===
{{Category see also|Magnesium minerals}}
{{See also|Boninite}}
Magnesium is the eighth-most-abundant element in the Earth's crust by mass and tied in seventh place with [[iron]] in [[molarity]].<ref name="Abundance">{{cite web|title=Abundance and form of the most abundant elements in Earth's continental crust|access-date=15 February 2008|url=http://www.gly.uga.edu/railsback/Fundamentals/ElementalAbundanceTableP.pdf|last=Railsback|first=L. Bruce|website=Some Fundamentals of Mineralogy and Geochemistry|archive-date=27 September 2011|archive-url=https://web.archive.org/web/20110927064201/http://www.gly.uga.edu/railsback/Fundamentals/ElementalAbundanceTableP.pdf|url-status=dead}}</ref> It is found in large deposits of [[magnesite]], [[Dolomite (mineral)|dolomite]], and other [[mineral]]s, and in mineral waters, where magnesium ion is soluble.<ref>{{Cite web |date=30 April 2013 |title=Magnesium EA65RS-T4 Alloy |url=https://www.azom.com/article.aspx?ArticleID=8683 |access-date=4 May 2024 |website=AZoM |language=en}}</ref>

Although magnesium is found in more than 60 [[mineral]]s, only dolomite, magnesite, [[brucite]], [[carnallite]], [[talc]], and [[olivine]] are of commercial importance.<ref>{{Cite web |title=Magnesium Statistics and Information {{!}} U.S. Geological Survey |url=https://www.usgs.gov/centers/national-minerals-information-center/magnesium-statistics-and-information |access-date=4 May 2024 |website=www.usgs.gov}}</ref>

The {{chem|Mg|2+}} [[cation]] is the second-most-abundant cation in seawater (about {{frac|1|8}} the mass of sodium ions in a given sample), which makes seawater and sea salt attractive commercial sources for Mg.

===Production quantities===
World production was approximately 1,100 kt in 2017, with the bulk being produced in China (930 kt) and Russia (60 kt).<ref>Bray, E. Lee (February 2019) [https://minerals.usgs.gov/minerals/pubs/commodity/magnesium/mcs-2019-mgmet.pdf Magnesium Metal]. Mineral Commodity Summaries, U.S. Geological Survey</ref> The United States was in the 20th century the major world supplier of this metal, supplying 45% of world production even as recently as 1995. Since the Chinese mastery of the Pidgeon process the US market share is at 7%, with a single US producer left as of 2013: US Magnesium, a [[Renco Group]] company located on the shores of the [[Great Salt Lake#Oil and minerals|Great Salt Lake]].<ref name="vardi">{{Cite web|last=Vardi|first=Nathan|title=Man With Many Enemies |url=https://www.forbes.com/forbes/2002/0722/044.html |date=6 June 2013 |website=Forbes|language=en}}</ref>

In September 2021, China took steps to reduce production of magnesium as a result of a government initiative to reduce energy availability for manufacturing industries, leading to a significant price increase.<ref>{{cite magazine |url=https://www.cips.org/supply-management/analysis/2022/february/what-to-do-about-the-magnesium-shortage/ |title=What to do about the magnesium shortage |magazine=Supply Management|date=17 February 2022 |archive-url=https://web.archive.org/web/20220217211243/https://www.cips.org/supply-management/analysis/2022/february/what-to-do-about-the-magnesium-shortage/ |archive-date=17 February 2022}}</ref>

=== Pidgeon and Bolzano processes===
[[File:محتویات درون ریتورت.jpg|thumb|right|An Iranian worker tends to the Pidgeon process]]
The [[Pidgeon process]] and the [[Bolzano process]] are similar.  In both, magnesium oxide is the precursor to magnesium metal.  The magnesium oxide is produced as a solid solution with calcium oxide by calcining the mineral [[dolomite (mineral)|dolomite]], which is a solid solution of calcium and magnesium carbonates:
:{{chem2|CaCO3*MgCO3 -> MgO*CaO  + 2 CO2}}
Reduction occurs at high temperatures with silicon. A ferrosilicon alloy is used rather than pure silicon as it is more economical. The iron component has no bearing on the reaction, having the simplified equation:{{citation needed|date=July 2024}}
:{{chem2|MgO*CaO +Si -> 2 Mg  + Ca2SiO4}}
The calcium oxide combines with silicon as the oxygen scavenger, yielding the very stable calcium silicate. The Mg/Ca ratio of the precursors can be adjusted by the addition of MgO or CaO.<ref name="AmundsenEtAll2003">{{cite book |doi=10.1002/14356007.a15_559 |chapter=Magnesium |title=Ullmann's Encyclopedia of Industrial Chemistry |date=2003|publisher=Wiley|location=Weinheim, Germany|display-authors=3 |last1=Amundsen |first1=Ketil |last2=Aune |first2=Terje Kr. |last3=Bakke |first3=Per |last4=Eklund |first4=Hans R. |last5=Haagensen |first5=Johanna Ö. |last6=Nicolas |first6=Carlos |last7=Rosenkilde |first7=Christian |last8=Van Den Bremt |first8=Sia |last9=Wallevik |first9=Oddmund |isbn=978-3-527-30385-4 }}</ref>

The Pidgeon and the Bolzano process differ in the details of the heating and the configuration of the reactor. Both generate gaseous Mg that is condensed and collected. The Pidgeon process dominates the worldwide production.<ref name=":1" /><ref name=":2">{{Cite web |title=Magnesium Processing {{!}} Techniques & Methods {{!}} Britannica |url=https://www.britannica.com/technology/magnesium-processing |access-date=16 April 2023 |website=www.britannica.com |language=en}}</ref> The Pidgeon method is less technologically complex and because of distillation/vapour deposition conditions, a high purity product is easily achievable.<ref name=":1">{{Cite book |title=Magnesium and its alloys : technology and applications |date=2020 |vauthors=Bamberger M, Dobrzański LA, Totten GE|isbn=978-1-351-04547-6 |edition=First |location=Boca Raton, FL|publisher=CRC Press, Inc. |oclc=1111577710}}</ref> China is almost completely reliant on the [[Silicothermic reaction|silicothermic]] Pidgeon process.

=== Dow process ===
{{anchor|Dow process}}
{{Redirect|Dow process (magnesium)|other Dow processes|Dow process (disambiguation)}}
Besides the Pidgeon process, the second most used process for magnesium production is [[electrolysis]]. This is a two step process. The first step is to prepare feedstock containing magnesium chloride and the second step is to dissociate the compound in [[electrolytic cell]]s as magnesium metal and [[Chlorine|chlorine gas]].<ref name=":2" />

To extract the magnesium, [[calcium hydroxide]] is added to the [[seawater]] to  [[precipitate]] [[magnesium hydroxide]].<ref>{{cite journal |last1=Battaglia |first1=Giuseppe |last2=Domina |first2=Maria Alda |last3=Lo Brutto |first3=Rita |last4=Lopez Rodriguez |first4=Julio |last5=Fernandez de Labastida |first5=Marc |last6=Cortina |first6=Jose Luis |last7=Pettignano |first7=Alberto |last8=Cipollina |first8=Andrea |last9=Tamburini |first9=Alessandro |last10=Micale |first10=Giorgio |title=Evaluation of the Purity of Magnesium Hydroxide Recovered from Saltwork Bitterns |journal=Water |date=21 December 2022 |volume=15 |issue=1 |pages=29 |doi=10.3390/w15010029 |doi-access=free |bibcode=2022Water..15...29B |hdl=2117/384847 |hdl-access=free }}</ref>
: {{chem|MgCl|2}} + {{chem|Ca(OH)|2}} → {{chem|Mg(OH)|2}} + {{chem|CaCl|2}}

Magnesium hydroxide ([[brucite]]) is poorly soluble in water and can be collected by filtration.  It reacts with [[hydrochloric acid]] to [[magnesium chloride]].<ref name=":2"/>
: {{chem|Mg(OH)|2}} + 2 HCl → {{chem|MgCl|2}} + 2 {{chem|H|2|O}}
From magnesium chloride, [[electrolysis]] produces magnesium.<ref>{{Cite web |title=Magnesium metal is produced by the electrolysis of molten magnesi... {{!}} Channels for Pearson+ |url=https://www.pearson.com/channels/general-chemistry/asset/95590f70/magnesium-metal-is-produced-by-the-electrolysis-of-molten-magnesium-chloride-usi |access-date=4 May 2024 |website=www.pearson.com |language=en}}</ref>

The basic reaction is as follows:
:{{chem2 | MgCl2 -> Mg(g) + Cl2(g) }}

The temperatures at which this reaction is operated is between 680 and 750&nbsp;°C.<ref name=":2" />

The magnesium chloride can be obtained using the [[Dow process (magnesium)|Dow process]], a process that mixes sea water and dolomite in a flocculator or by dehydration of magnesium chloride brines. The electrolytic cells are partially submerged in a molten salt electrolyte to which the produced magnesium chloride is added in concentrations between 6–18%.<ref name=":2" /> This process does have its share of disadvantages including production of harmful [[chlorine gas]] and the overall reaction being very energy intensive, creating environmental risks.<ref name=lee21>{{Cite journal |last1=Lee |first1=Tae-Hyuk |last2=Okabe |first2=Toru H. |last3=Lee |first3=Jin-Young |last4=Kim |first4=Young Min |last5=Kang |first5=Jungshin |date=September 2021 |title=Development of a novel electrolytic process for producing high-purity magnesium metal from magnesium oxide using a liquid tin cathode |journal=Journal of Magnesium and Alloys |language=en |volume=9 |issue=5 |pages=1644–1655 |doi=10.1016/j.jma.2021.01.004|s2cid=233930398 |doi-access=free }}</ref> The Pidgeon process is more advantageous regarding its simplicity, shorter construction period, low power consumption and overall good magnesium quality compared to the electrolysis method.<ref name=":0" />

In the United States, magnesium was once obtained principally with the Dow process in [[Corpus Christi TX]], by [[electrolysis]] of fused magnesium chloride from [[brine]] and [[sea water]]. A saline solution containing {{chem|Mg|2+}} ions is first treated with [[Calcium oxide|lime]] (calcium oxide) and the precipitated [[magnesium hydroxide]] is collected:
:{{chem|Mg|2+}}(aq) + {{chem|CaO}}(s) + {{chem|H|2|O}}(l) → {{chem|Ca|2+}}(aq) + {{chem|Mg(OH)|2}}(s)

The hydroxide is then converted to [[magnesium chloride]] by treatment with [[hydrochloric acid]] and heating of the product to eliminate water:
:{{chem2|Mg(OH)2 + 2 HCl → MgCl2  +  2 H2O}}

The salt is then electrolyzed in the molten state. At the [[cathode]], the {{chem|Mg|2+}} ion is reduced by two [[electron]]s to magnesium metal:
:{{chem|Mg|2+}} + 2{{Subatomic particle|electron}} → Mg

At the [[anode]], each pair of {{chem|Cl|-}} ions is oxidized to [[chlorine]] gas, releasing two electrons to complete the circuit:
:2{{chem|Cl|-}} → {{chem|Cl|2}}(g) + 2{{Subatomic particle|electron}}

===Carbothermic process===
The [[Carbothermic reaction|carbothermic]] route to magnesium has been recognized as a low energy, yet high productivity path to magnesium extraction. The chemistry is as follows:
[[File:Rotary kiln Johannsen patent US1618204.png|thumb|The rotary kiln is used for calcination]]
{{chem2|C + MgO -> CO + Mg}}

A disadvantage of this method is that slow cooling the vapour can cause the reaction to quickly revert. To prevent this from happening, the magnesium can be dissolved directly in a suitable metal solvent before reversion starts happening. Rapid [[quenching]] of the vapour can also be performed to prevent reversion.<ref>{{Cite journal |last1=Brooks |first1=Geoffrey |last2=Trang |first2=Simon |last3=Witt |first3=Peter |last4=Khan |first4=M. N. H. |last5=Nagle |first5=Michael |date=May 2006 |title=The carbothermic route to magnesium |url=http://dx.doi.org/10.1007/s11837-006-0024-x |journal=JOM |volume=58 |issue=5 |pages=51–55 |doi=10.1007/s11837-006-0024-x |bibcode=2006JOM....58e..51B |s2cid=67763716 |issn=1047-4838|url-access=subscription }}</ref>

=== YSZ process ===
{{anchor|YSZ process}}
A newer process, solid oxide membrane technology, involves the electrolytic reduction of MgO. At the cathode, {{chem|Mg|2+}} ion is reduced by two [[electron]]s to magnesium metal. The electrolyte is [[yttria-stabilized zirconia]] (YSZ). The anode is a liquid metal. At the YSZ/liquid metal anode {{chem|O|2-}} is oxidized. A layer of graphite borders the liquid metal anode, and at this interface carbon and oxygen react to form carbon monoxide. When silver is used as the liquid metal anode, there is no reductant carbon or hydrogen needed, and only oxygen gas is evolved at the anode.<ref name="pal07">{{cite journal|last1=Pal|first1=Uday B. |last2=Powell|first2=Adam C.|title=The Use of Solid-Oxide-Membrane Technology for Electrometallurgy|date=2007|bibcode=2007JOM....59e..44P|volume=59|pages=44–49|journal=JOM|doi=10.1007/s11837-007-0064-x|issue=5|s2cid=97971162 }}</ref> It was reported in 2011 that this method provides a 40% reduction in cost per pound over the electrolytic reduction method.<ref>{{cite web|url=http://www1.eere.energy.gov/vehiclesandfuels/pdfs/merit_review_2011/lightweight_materials/lm035_derezinski_2011_o.pdf| archive-url=https://web.archive.org/web/20131113035743/http://www1.eere.energy.gov/vehiclesandfuels/pdfs/merit_review_2011/lightweight_materials/lm035_derezinski_2011_o.pdf| url-status=dead| archive-date=13 November 2013|publisher=MOxST| title=Solid Oxide Membrane (SOM) Electrolysis of Magnesium: Scale-Up Research and Engineering for Light-Weight Vehicles |first=Steve| last=Derezinski |date=12 May 2011| access-date=27 May 2013}}</ref>

=== Rieke process ===
Rieke et al. developed a "general approach for preparing highly reactive metal powders by reducing metal salts in ethereal or hydrocarbon solvents using alkali metals as reducing agents" now known as the [[Rieke process]].<ref name="rieke16">{{cite book |doi=10.1002/9781118929124.ch4 |chapter=Magnesium |title=Chemical Synthesis Using Highly Reactive Metals |date=2017 |pages=161–208 |isbn=978-1-118-92911-7 }}</ref> Rieke finalized the identification of [[Rieke metals]] in 1989,<ref name="rieke95">{{cite book |doi=10.1002/9783527615179.ch01 |chapter=Rieke Metals: Highly Reactive Metal Powders Prepared by Alkali Metal Reduction of Metal Salts |title=Active Metals |date=1995 |last1=Rieke |first1=Reuben D. |last2=Sell |first2=Matthew S. |last3=Klein |first3=Walter R. |last4=Chen |first4=Tian-An |last5=Brown |first5=Jeffrey D. |last6=Hanson |first6=Mark V. |pages=1–59 |isbn=978-3-527-29207-3 }}</ref> one of which was Rieke-magnesium, first produced in 1974.<ref name="rieke74">{{cite journal |doi=10.1002/chin.197421315 |title=ChemInform Abstract: ACTIVATED METALS PART 4, PREPARATION AND REACTIONS OF HIGHLY REACTIVE MAGNESIUM METAL |date=1974 |last1=Rieke |first1=Reuben D. |last2=Bales |first2=Stephen E. |journal=Chemischer Informationsdienst |volume=5 |issue=21 |article-number=chin.197421315 }}</ref>

== History ==
The name magnesium originates from the [[Ancient Greek|Greek]] word for locations related to the tribe of the [[Magnetes]], either a district in [[Thessaly]] called [[Ancient Magnesia|Magnesia]]<ref>{{Greenwood&Earnshaw2nd|page=108}}</ref> or [[Magnesia ad Sipylum]], now in Turkey.<ref name="LanguageHAt">{{cite web |last1=languagehat |title=Magnet |url=http://languagehat.com/magnet/ |website=languagehat.com |access-date=18 June 2020 |language=en |date=28 May 2005}}</ref> It is related to [[magnetite]] and [[manganese]], which also originated from this area, and required differentiation as separate substances. See [[manganese]] for this history.

In 1618, a farmer at Epsom in England attempted to give his cows water from a local well. The cows refused to drink because of the water's bitter taste, but the farmer noticed that the water seemed to heal scratches and rashes. The substance obtained by evaporating the water became known as [[Magnesium sulfate|Epsom salts]] and its fame spread.<ref>{{cite journal|last1=Ainsworth|first1=Steve|title=Epsom's deep bath|journal=Nurse Prescribing|date=1 June 2013|volume=11|issue=6|page=269|doi=10.12968/npre.2013.11.6.269}}</ref> It was eventually recognized as hydrated magnesium sulfate, {{chem|MgSO|4}}·7{{hsp}}{{chem|H|2|O}}.<ref>{{Cite web |last=PubChem |title=Magnesium Sulfate Heptahydrate |url=https://pubchem.ncbi.nlm.nih.gov/compound/24843 |access-date=28 April 2024 |website=pubchem.ncbi.nlm.nih.gov |language=en}}</ref>

The metal itself was first isolated by [[Humphry Davy|Sir Humphry Davy]] in England in 1808. He used electrolysis on a mixture of [[magnesia alba|magnesia]] and [[Mercury(II) oxide|mercuric oxide]].<ref name="Davy1808">{{cite journal| last = Davy | first = H. | date= 1808 | title = Electro-chemical researches on the decomposition of the earths; with observations on the metals obtained from the alkaline earths, and on the amalgam procured from ammonia | journal = Philosophical Transactions of the Royal Society of London | volume = 98 | pages = 333–370|bibcode = 1808RSPT...98..333D | jstor=107302 | doi=10.1098/rstl.1808.0023| s2cid = 96364168 }}</ref> [[Antoine Bussy]] prepared it in coherent form in 1831. Davy's first suggestion for a name was 'magnium',<ref name="Davy1808" /> but the name magnesium is now used in most European languages.<ref>{{Cite web |title=Magnesium (Mg) – Periodic Table |url=https://www.periodictable.one/element/12 |access-date=4 May 2024 |website=www.periodictable.one |language=en}}</ref>

Further discoveries about magnesium were made by the father of [[physical chemistry]] in [[Imperial Russia]], [[Nikolai Beketov]] (1827–1911), who established that magnesium and zinc displaced other metals from their salts under high temperatures.

==Uses==

===Magnesium metal===

[[File:Bundesarchiv Bild 102-12062, Wasserreiter mit Magnesiumfackeln.jpg|thumb|An unusual application of magnesium as an [[Illumination (lighting)|illumination]] source while [[wakeskating]] in 1930]]

Magnesium is the third-most-commonly-used structural metal, following [[iron]] and aluminium.<ref>{{Cite book|url=https://books.google.com/books?id=9DskDwAAQBAJ&pg=PT256|title=Materials for the 21st Century|last=Segal|first=David|date=2017|publisher=Oxford University Press|isbn=978-0192526090}}</ref> The main applications of magnesium are, in order: aluminium alloys, [[die-casting]] (alloyed with [[zinc]]),<ref name="BakerM. M. Avedesian1999">{{cite book|last1=Baker|first1=Hugh D. R.|last2=Avedesian|first2=Michael|title=Magnesium and magnesium alloys|date=1999|publisher=Materials Information Society|location=Materials Park, OH|isbn=978-0871706577|page=4}}</ref> removing [[sulfur]] in the production of iron and steel, and the production of [[titanium]] in the [[Kroll process]].<ref name="AmundsenEtAll2003"/>

Magnesium is used in lightweight materials and alloys. For example, when infused with silicon carbide [[nanoparticle]]s, it has extremely high specific strength.<ref name="ucla">{{cite web|url=http://newsroom.ucla.edu/releases/ucla-researchers-create-exceptionally-strong-and-lightweight-new-metal |title=UCLA researchers create super-strong magnesium metal |publisher=ucla.edu |first=Matthew |last=Chin |date=23 December 2015 }}</ref>

Historically, magnesium was one of the main aerospace construction metals and was used for German military aircraft as early as World War I and extensively for German aircraft in World War II. The Germans coined the name "[[Elektron (alloy)|Elektron]]" for magnesium alloy, a term which is still used today. In the commercial aerospace industry, magnesium was generally restricted to engine-related components, due to fire and corrosion hazards. Magnesium alloy use in aerospace is increasing in the 21st century, driven by the importance of fuel economy.<ref name="aghion00">{{cite journal |doi= 10.4028/www.scientific.net/MSF.350-351.19 |title= Magnesium Alloys Development towards the 21st Century |date= 2000 |last1= Aghion |first1= E. |last2= Bronfin |first2= B. |journal= Materials Science Forum |volume= 350–351 |pages= 19–30|s2cid= 138429749 }}</ref> Magnesium alloys can act as replacements for aluminium and steel alloys in structural applications.<ref name=shu10>{{cite journal |last1=Shu |first1=Dong Wei |last2=Ahmad |first2=Iram Raza |title=Magnesium Alloys: An Alternative for Aluminium in Structural Applications |journal=Advanced Materials Research |date=December 2010 |volume=168–170 |pages=1631–1635 |doi=10.4028/www.scientific.net/amr.168-170.1631 }}</ref><ref name=ma17>{{cite web | title=Magnesium alloy as a lighter alternative to aluminum alloy | website=Phys.org | date=29 November 2017 |url=https://phys.org/news/2017-11-magnesium-alloy-lighter-alternative-aluminum.html }}</ref>

====Aircraft====
* [[Wright Aeronautical]] used a magnesium [[crankcase]] in the WWII-era [[Wright R-3350 Duplex Cyclone]] aviation engine. This presented a serious problem for the earliest models of the [[Boeing B-29 Superfortress]] heavy bomber when an in-flight engine fire ignited the engine crankcase. The resulting combustion was as hot as 5,600&nbsp;°F (3,100&nbsp;°C) and could sever the wing spar from the [[fuselage]].<ref name="Dreizin, Edward L.; Berman, Charles H. and Vicenzi, Edward P. 2000 30"/><ref>{{cite book |url=https://books.google.com/books?id=EBmynsBj2BUC&pg=PA40| pages=40–41 | title = Mission to Tokyo: The American Airmen Who Took the War to the Heart of Japan | isbn = 978-1610586634 | last1 = Dorr | first1 = Robert F. | date = 2012| publisher=Zenith Press }}</ref><ref>{{cite book |url=https://books.google.com/books?id=JEwpAQAAIAAJ | title=AAHS Journal |volume=44–45 | date=1999 |publisher=American Aviation Historical Society }}</ref>

====Automotive====
[[File:Bugatti Aérolithe AV.jpg|thumb|The [[Bugatti Type 57#1935 Bugatti Type 57 Aérolithe Chassis No. 57331 Prototype|Bugatti Type 57 Aérolithe]] featured a lightweight body made of [[Elektron (alloy)|Elektron]], a trademarked magnesium alloy.]]
* [[Mercedes-Benz]] used the alloy [[Elektron (alloy)|Elektron]] in the bodywork of an early model [[Mercedes-Benz 300 SLR]]; these cars competed in the [[1955 World Sportscar Championship]] including a win at the [[1955 Mille Miglia|Mille Miglia]], and at [[24 Hours of Le Mans|Le Mans]] where one was involved in the [[1955 Le Mans disaster]] when spectators were showered with burning fragments of Elektron.<ref>{{cite news |last1=Spurgeon |first1=Brad |title=On Auto Racing's Deadliest Day |url=https://www.nytimes.com/2015/06/12/sports/autoracing/on-auto-racings-deadliest-day.html |work=The New York Times |date=11 June 2015 }}</ref>
* [[Porsche]] used magnesium alloy frames in the [[Porsche 917|917/053]] that won Le Mans in 1971, and continues to use magnesium alloys for its engine blocks due to the weight advantage.<ref>{{Cite web |last=Perkins |first=Chris |date=1 July 2021 |title=The 1971 Porsche 917 KH Had a Chassis Made of Ultra-Flammable Magnesium |url=https://www.roadandtrack.com/car-culture/a36902927/1971-porsche-917-kh-magnesium/ |access-date=7 May 2023 |website=Road & Track |language=en-US}}</ref>
* [[Volkswagen Group]] has used magnesium in its engine components for many years.<ref>{{Cite web|date=18 August 2020|title=1950: The metal is magnesium, the car is the Beetle|url=https://www.hydro.com/en-US/about-hydro/company-history/1946---1977/1950-the-metal-is-magnesium-the-car-is-the-beetle/|access-date=5 April 2021|website=hydro.com|language=en-us}}</ref>
* [[Mitsubishi Motors]] uses magnesium for its [[paddle shifters]].<ref>{{Cite web |date=12 April 2006 |title=2007 Mitsubishi Outlander brings sport sedan dynamics to compact sport-utility vehicle segment; performance credentials include 220 Hp V-6, 6-speed Sportronic(R) transmission and aluminum roof |url=http://media.mitsubishicars.com/en-US/releases/2007-mitsubishi-outlander-brings-sport-sedan-dynamics-to-compact-sport-utility-vehicle-segment-performance-credentials-include-220-hp-v-6-6-speed-sportronicr-transmission-and-aluminum-roof |access-date=7 May 2023 |website=Mitsubishi Newsroom |language=en}}</ref>
* [[BMW]] used magnesium alloy blocks in their [[BMW N52|N52]] engine, including an aluminium alloy insert for the cylinder walls and cooling jackets surrounded by a high-temperature magnesium alloy [[AJ alloys|AJ62A]]. The engine was used worldwide between 2005 and 2011 in various 1, 3, 5, 6, and 7 series models; as well as the Z4, X1, X3, and X5.<ref>{{cite journal |first1=Sachin |last1=Kumar |first2=Chuansong |last2=Wu |title=Review:Mg and Its Alloy——Scope, Future Perspectives and Recent Advancements in Welding and Processing |journal=Journal of Harbin Institute of Technology |date=2017 |volume=24 |issue=6 |pages=1–37 |doi=10.11916/j.issn.1005-9113.17065 }}</ref>
* [[Chevrolet]] used the magnesium alloy AE44 in the 2006 Corvette [[Corvette C6|Z06]].<ref>{{Cite book |last1=Aragones |first1=Jonathon |last2=Goundan |first2=Kasi |last3=Kolp |first3=Scott |last4=Osborne |first4=Richard |last5=Ouimet |first5=Larry |last6=Pinch |first6=William |title=SAE Technical Paper Series |date=11 April 2005 |chapter=Development of the 2006 Corvette Z06 Structural Cast Magnesium Crossmember |volume=1 |article-number=2005-01-0340 |chapter-url=https://www.sae.org/publications/technical-papers/content/2005-01-0340/ |language=English |location=Warrendale, PA|doi=10.4271/2005-01-0340 }}</ref>
Both AJ62A and AE44 are recent developments in high-temperature low-[[Creep (deformation)|creep]] magnesium alloys. The general strategy for such alloys is to form [[intermetallic]] precipitates at the [[crystallite|grain boundaries]], for example by adding [[mischmetal]] or [[calcium]].<ref>{{cite report|title=Tensile and Compressive Creep of Magnesium-Aluminum-Calcium Based Alloys |date=2001 |author=Luo, Alan A. |author2=Powell, Bob R. |name-list-style=amp |publisher=Materials & Processes Laboratory, General Motors Research & Development Center |access-date=21 August 2007 |url=http://doc.tms.org/ezmerchant/prodtms.nsf/productlookupitemid/01-481x-137/%24FILE/01-481X-137F.pdf |archive-url=https://web.archive.org/web/20070928023445/http://doc.tms.org/ezmerchant/prodtms.nsf/productlookupitemid/01-481x-137/%24FILE/01-481X-137F.pdf |archive-date=28 September 2007 |url-status=dead }}</ref>

====Electronics====
Because of low density and good mechanical and electrical properties, magnesium is used for manufacturing of mobile phones, laptop and [[tablet computers]], cameras, and other electronic components.<ref>{{Cite journal |date=2020 |title=Evaluation of Mechanical Properties of Magnesium [AZ91] Reinforced With Carbon Nanotubes And Sic/Al2O3 |url=https://www.ilkogretim-online.org/fulltext/218-1642679175.pdf |journal=Elementary Education Online |volume=19 |issue=4 |page=6907 |access-date=7 May 2023 |archive-date=7 May 2023 |archive-url=https://web.archive.org/web/20230507094851/https://www.ilkogretim-online.org/fulltext/218-1642679175.pdf |url-status=dead }}</ref> It was used as a premium feature because of its light weight in some 2020 laptops.<ref name="bma">{{cite news |last1=Dignan |first1=Larry |title=Blue magnesium alloy laptops: Premium price, plastic feel, but lightweight |url=https://www.zdnet.com/article/blue-magnesium-alloy-laptops-premium-price-plastic-feel-but-lightweight/ |publisher=ZDNet |date=2 January 2020}}</ref>
[[File:Magnesium-products.jpg|thumb|left|Products made of magnesium: firestarter and shavings, sharpener, magnesium ribbon]]

====Source of light====
{{anchor|Flammability}}Magnesium is flammable, burning at a temperature of approximately {{convert|3100|°C|K °F|abbr=on}},<ref name="Dreizin, Edward L.; Berman, Charles H. and Vicenzi, Edward P. 2000 30" /> and the [[autoignition temperature]] of magnesium ribbon is approximately {{convert|473|°C|K °F|abbr=on}}.<ref>{{cite web| title=Magnesium (Powder)| work=International Programme on Chemical Safety (IPCS)| publisher = IPCS INCHEM |date=April 2000 |url=http://www.inchem.org/documents/icsc/icsc/eics0289.htm| access-date=21 December 2011}}</ref> Magnesium's high combustion temperature makes it a useful tool for starting emergency fires. When burning in air, magnesium produces a brilliant white light that includes strong ultraviolet wavelengths.

Magnesium powder ([[flash powder]]) was used for subject illumination in the early days of [[photography]].<ref>{{cite book |last1=Hannavy |first1=John |title=Encyclopedia of Nineteenth-Century Photography |date=2013 |publisher=Routledge |isbn=978-1-135-87327-1 |page=84 }}</ref><ref>{{Cite book|url=https://books.google.com/books?id=H3E3AQAAMAAJ|title=Scientific American: Supplement|year=1899|publisher=Munn and Company|volume=48|page=20035}}</ref> Magnesium filament used in electrically ignited single-use photography [[Flash (photography)#Flashbulbs|flashbulbs]] replaced this usage eventually. Magnesium powder is used in [[fireworks]] and marine [[flare]]s where a brilliant light is required, and in trick self-relighting birthday candles. It was also used for various theatrical effects,<ref>{{Cite book|url=https://archive.org/details/bub_gb_gQkEAAAAMBAJ|title=Billboard|year=1974|publisher=Nielsen Business Media, Inc.|page=[https://archive.org/details/bub_gb_gQkEAAAAMBAJ/page/n19 20]}}</ref> such as lightning,<ref>{{cite book |last1=Altman |first1=Rick |title=Silent Film Sound |date=2004 |publisher=Columbia University Press |isbn=978-0-231-11663-3 |page=41 }}</ref> pistol flashes,<ref>{{cite book |last1=Lindsay |first1=David |title=Madness in the Making: The Triumphant Rise and Untimely Fall of America's Show Inventors |date=2005 |publisher=iUniverse |isbn=978-0-595-34766-7 |page=210 }}</ref> and supernatural appearances.<ref>{{cite book |last1=McCormick |first1=John |last2=Pratasik |first2=Bennie |title=Popular Puppet Theatre in Europe, 1800-1914 |date=2005 |publisher=Cambridge University Press |isbn=978-0-521-61615-7 |page=106 }}</ref>

Magnesium is often used to ignite thermite or other materials that require a high ignition temperature. Magnesium continues to be used as an [[Incendiary device|incendiary]] element in warfare.<ref>{{cite web| title=9N510 (ML-5) Submunition|url=https://cat-uxo.com/explosive-hazards/submunitions/9n510-ml-5-submunition|access-date=22 November 2022|publisher= Collective Awareness to UXO}}</ref>[[File:Magnesium Sparks.jpg|thumb|Magnesium firestarter (in left hand), used with a [[pocket knife]] and [[flint]] to create sparks that ignite the shavings]]

Flame temperatures of magnesium and magnesium alloys can reach {{convert|3100|C|F|abbr=on}},<ref name="Dreizin, Edward L.; Berman, Charles H. and Vicenzi, Edward P. 2000 30">{{cite journal|title=Condensed-phase modifications in magnesium particle combustion in air|author=Dreizin, Edward L.|author2=Berman, Charles H.|author3=Vicenzi, Edward P.|name-list-style=amp|journal=Scripta Materialia|volume=122|issue=1–2|doi=10.1016/S0010-2180(00)00101-2|date=2000|pages=30–42|bibcode=2000CoFl..122...30D |citeseerx=10.1.1.488.2456}}</ref> although flame height above the burning metal is usually less than {{convert|300|mm|in|abbr=on}}.<ref name="DOE">{{cite book |title=DOE Handbook – Primer on Spontaneous Heating and Pyrophoricity |publisher=[[United States Department of Energy]] |id=DOE-HDBK-1081-94 |date=December 1994 |page=20 |url=http://www.hss.doe.gov/nuclearsafety/techstds/docs/handbook/hbk1081c.html#ZZ22  |access-date   = 21 December 2011 |archive-url=https://web.archive.org/web/20120415172328/http://www.hss.doe.gov/nuclearsafety/techstds/docs/handbook/hbk1081c.html#ZZ22 |archive-date=15 April 2012 |url-status=dead
}}</ref> Once ignited, such fires are difficult to extinguish because they resist several substances commonly used to put out fires; combustion continues in [[nitrogen]] (forming [[magnesium nitride]]),<ref name="Brauer">{{cite book |last1=Ehrlich |first1=P. |editor1-last=Brauer |editor1-first=Georg |title=Handbook of Preparative Inorganic Chemistry 1 |date=1 December 1963 |publisher=Academic Press |location=New York, London |isbn=978-0121266011 |pages=916–917 |edition=Second |chapter-url=https://archive.org/details/Handbook_of_Preparative_Inorganic_Chemistry_1_2_Brauer/page/n939/mode/2up |access-date=29 March 2025 |language=en |chapter=Section 17: Alkaline Earth Metals}}</ref> in [[carbon dioxide]] (forming [[magnesium oxide]] and [[carbon]]),<ref name=CO2/> and in water (forming magnesium oxide and hydrogen, which also combusts due to heat in the presence of additional oxygen). This property{{which|reason=Were there giant swimming pools, CO2 pits, and Nitrogen refineries everywhere?|date=March 2025}}  was used in incendiary weapons during the [[firebombing]] of cities in [[World War II]], where the only practical [[civil defense]] was to smother a burning flare under dry sand{{why|reason=Magnesium exothermically reacts with sand to produce the silicide;  proper extinguishers are salt based|date=March 2025}} to exclude atmosphere from the combustion.{{citation needed|date=March 2025}}

====Chemical reagent====
In the form of turnings or ribbons, to prepare [[Grignard reagent]]s, which are useful in [[organic synthesis]].<ref>{{Cite web |last=Ashenhurst |first=James |date=14 October 2011 |title=Grignard Reagents For Addition To Aldehydes and Ketones |url=https://www.masterorganicchemistry.com/2011/10/14/reagent-friday-grignard-reagents/ |access-date=4 May 2024 |website=Master Organic Chemistry |language=en-US}}</ref>

====Other====
* In the production of [[Ductile iron|nodular graphite in cast iron]].<ref name=LANL_Mg>{{Cite web |title=Periodic Table of Elements: Los Alamos National Laboratory |url=https://periodic.lanl.gov/12.shtml |access-date=4 May 2024 |website=periodic.lanl.gov}}</ref>
* As an additive agent in conventional propellants.<ref name=LANL_Mg/>
* As a reducing agent to separate [[uranium]] and other metals from their [[Salt (chemistry)|salts]].<ref>{{cite journal |last1=Ainscough |first1=J.B. |last2=Rigby |first2=F |title=Magnesium reduction of uranium oxide |journal=Journal of Inorganic and Nuclear Chemistry |date=July 1974 |volume=36 |issue=7 |pages=1531–1534 |doi=10.1016/0022-1902(74)80618-4 }}</ref>
* As a [[Sacrificial anode|sacrificial (galvanic) anode]] to protect boats, underground tanks, pipelines, buried structures, and water heaters.<ref>{{Cite web |date=2 October 2013 |title=Sacrificial Anode |url=https://chem.libretexts.org/Bookshelves/Analytical_Chemistry/Supplemental_Modules_(Analytical_Chemistry)/Electrochemistry/Exemplars/Corrosion/Sacrificial_Anode |access-date=4 May 2024 |website=Chemistry LibreTexts |language=en}}</ref>
* Alloyed with zinc to produce the zinc sheet used in [[photoengraving]] plates in the printing industry, [[Dry cell|dry-cell battery]] walls, and [[Flashing (weatherproofing)|roofing]].<ref name="BakerM. M. Avedesian1999" />
* Alloyed with aluminium with aluminium-magnesium alloys being used mainly for [[beverage can]]s,<ref>{{Cite web |last=Multiview |date=17 December 2019 |title=Strong and Ductile: Magnesium Adds Benefits to Aluminum Alloys |url=https://www.belmontmetals.com/strong-and-ductile-magnesium-added-to-aluminum-alloys-provides-amazing-benefits/ |access-date=4 May 2024 |website=Belmont Metals |language=en-US}}</ref> sports equipment such as golf clubs,<ref>{{Cite web|url=https://www.hirekogolf.com/clubheads-material-differences|title=Golf Clubheads: Material Differences|website=www.hirekogolf.com}}</ref> fishing reels,<ref>{{Cite web |last=Purnell |first=Ross |title=How Aluminum Changed Fly Fishing Forever |url=https://www.flyfisherman.com/editorial/how-aluminum-changed-fly-fishing/152036 |access-date=4 May 2024 |website=Fly Fisherman |language=en}}</ref> and [[archery|bows and arrows]].<ref>{{Cite web |title=Compound Bow – Facts and History of Modern Bows |url=http://www.historyofarchery.com/archery-history/compound-bow/ |access-date=4 May 2024 |website=www.historyofarchery.com}}</ref>
* Many car and aircraft manufacturers have made engine and body parts from magnesium.<ref>{{Cite web |title=Automotive Applications – International Magnesium Association |url=https://www.intlmag.org/page/app_automotive_ima |access-date=4 May 2024 |website=www.intlmag.org }}{{Dead link|date=July 2025 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>
* [[Magnesium battery|Magnesium batteries]] have been commercialized as [[primary battery|primary batteries]], and are an active topic of research for [[Rechargeable battery|rechargeable batteries]], such as [[Magnesium sulfur battery|magnesium sulfur batteries]].<ref>{{cite journal |last1=Leong |first1=Kee Wa |last2=Pan |first2=Wending |last3=Wang |first3=Yifei |title=Reversibility of a High-Voltage, Cl – Regulated, Aqueous Mg Metal Battery Enabled by a Water-in-Salt Electrolyte |journal=ACS Energy Lett. |date=21 July 2022 |volume=7 |issue=8 |pages=2657–2666 |doi=10.1021/acsenergylett.2c01255 |bibcode=2022ACSEL...7.2657L |s2cid=250965568 |url=https://pubs.acs.org/doi/10.1021/acsenergylett.2c01255 |access-date=25 June 2023|url-access=subscription }}</ref><ref>{{cite journal |last1=Wang |first1=Fei |last2=Fan |first2=Xiulin |last3=Gao |first3=Tao |last4=Sun |first4=Wei |last5=Ma |first5=Zhaohui |last6=Yang |first6=Chongyin |last7=Han |first7=Fudong |last8=Xu |first8=Kang |last9=Wang |first9=Chunsheng |title=High-Voltage Aqueous Magnesium Ion Batteries |journal=ACS Central Science |date=25 October 2017 |volume=3 |issue=10 |pages=1121–1128 |doi=10.1021/acscentsci.7b00361 |pmid=29104929 |pmc=5658756 }}</ref>

===Compounds===
Magnesium compounds, primarily [[magnesium oxide]] (MgO), are used as a [[refractory]] material in [[Metallurgical furnace|furnace]] linings for producing [[iron]], [[steel]], [[nonferrous metal]]s, [[glass]], and [[cement]]. Magnesium oxide and other magnesium compounds are also used in the agricultural, chemical, and construction industries. Magnesium oxide from [[calcination]] is used as an electrical insulator in [[Mineral-insulated copper-clad cable|fire-resistant cables]].<ref>{{cite book|last=Linsley|first=Trevor|title=Basic Electrical Installation Work|isbn=978-0080966281|page=362|date=2011|chapter=Properties of conductors and insulators|publisher=Taylor & Francis }}</ref>

Magnesium reacts with [[haloalkane]]s to give [[Grignard reagent]]s, which are used for a wide variety of [[organic reaction]]s forming [[carbon–carbon bond]]s.<ref>{{cite book |last=Wade Jr. |first=L. G. |year=2012 |edition=8th |title=Organic Chemistry |publisher=Pearson |page=441 |isbn=978-0321768414}}</ref>

Magnesium salts are included in various [[food]]s,<ref>{{Cite web |title=Magnesium-Rich Food Information |url=https://my.clevelandclinic.org/health/articles/15650-magnesium-rich-food |access-date=4 May 2024 |website=Cleveland Clinic |language=en}}</ref> [[fertilizer]]s<ref>{{Cite web |title=Magnesium for crop production |url=https://extension.umn.edu/micro-and-secondary-macronutrients/magnesium-crop-production |access-date=4 May 2024 |website=extension.umn.edu |language=en}}</ref> (magnesium is a component of [[chlorophyll]]<ref>{{cite journal |last1=Ishfaq |first1=Muhammad |last2=Wang |first2=Yongqi |last3=Yan |first3=Minwen |last4=Wang |first4=Zheng |last5=Wu |first5=Liangquan |last6=Li |first6=Chunjian |last7=Li |first7=Xuexian |title=Physiological Essence of Magnesium in Plants and Its Widespread Deficiency in the Farming System of China |journal=Frontiers in Plant Science |date=25 April 2022 |volume=13 |article-number=802274 |doi=10.3389/fpls.2022.802274 |doi-access=free |pmid=35548291 |pmc=9085447 |bibcode=2022FrPS...1302274I }}</ref>), and [[culture medium|microbe culture media]].<ref>{{cite journal |last1=Christensen |first1=David G. |last2=Orr |first2=James S. |last3=Rao |first3=Christopher V. |last4=Wolfe |first4=Alan J. |title=Increasing Growth Yield and Decreasing Acetylation in Escherichia coli by Optimizing the Carbon-to-Magnesium Ratio in Peptide-Based Media |journal=Applied and Environmental Microbiology |date=15 March 2017 |volume=83 |issue=6 |article-number=e03034-16 |doi=10.1128/AEM.03034-16 |pmid=28062462 |pmc=5335519 |bibcode=2017ApEnM..83E3034C }}</ref>

[[Magnesium sulfite]] is used in the manufacture of [[paper]] ([[sulfite process]]).<ref>{{Cite web |title=Magnesium sulfite - Hazardous Agents {{!}} Haz-Map |url=https://haz-map.com/Agents/20720 |access-date=4 May 2024 |website=haz-map.com}}</ref>

[[Magnesium phosphate]] is used to fireproof wood used in construction.<ref>{{cite journal |last1=Yan |first1=Long |last2=Xu |first2=Zhisheng |last3=Liu |first3=Dingli |title=Synthesis and application of novel magnesium phosphate ester flame retardants for transparent intumescent fire-retardant coatings applied on wood substrates |journal=Progress in Organic Coatings |date=April 2019 |volume=129 |pages=327–337 |doi=10.1016/j.porgcoat.2019.01.013 }}</ref>

Magnesium hexafluorosilicate is used for moth-proofing [[textile]]s.<ref>{{Cite web |title=NCATS Inxight Drugs — MAGNESIUM HEXAFLUOROSILICATE |url=https://drugs.ncats.io/substance/H37V80D2JS |access-date=4 May 2024 |website=drugs.ncats.io |language=en}}</ref>

== Biological roles ==
{{Main|Magnesium in biology|Magnesium (medical use)}}

===Mechanism of action===
The important interaction between [[phosphate]] and magnesium ions makes magnesium essential to the basic [[nucleic acid]] chemistry of all cells of all known living organisms. More than 300 [[enzyme]]s require magnesium ions for their catalytic action, including all enzymes using or synthesizing [[Adenosine triphosphate|ATP]] and those that use other [[nucleotides]] to synthesize [[DNA]] and [[RNA]]. The ATP molecule is normally found in a [[Chelation|chelate]] with a magnesium ion.<ref>
{{cite book
| first1=Andrea, M.P.
| last1=Romani
| chapter=Magnesium in Health and Disease
|editor=Astrid Sigel
|editor2=Helmut Sigel
|editor3=Roland K. O. Sigel
|title=Interrelations between Essential Metal Ions and Human Diseases
|series=Metal Ions in Life Sciences
|volume=13
|date=2013
|publisher=Springer
|pages=49–79
|doi=10.1007/978-94-007-7500-8_3
| pmid=24470089
| isbn=978-94-007-7499-5
}}
</ref>

=== Nutrition ===
Magnesium intake—especially from diet—may modestly lower [[blood pressure]] and reduce risks of [[stroke]] and [[Cardiac arrest|sudden cardiac death]], but evidence is mixed, effects are small, and more robust [[clinical trial]]s are needed to clarify its role in [[cardiovascular disease]] prevention.<ref>{{Cite web |title=Office of Dietary Supplements – Magnesium |url=https://ods.od.nih.gov/factsheets/Magnesium-HealthProfessional/ |access-date=15 June 2025 |website=ods.od.nih.gov |language=en}}</ref>

====Diet====
[[File:FoodSourcesOfMagnesium.jpg|thumb|alt=refer to caption; follow link for complete description|Examples of food sources of magnesium (clockwise from top left): bran muffins, pumpkin seeds, barley, buckwheat flour, low-fat vanilla yogurt, trail mix, halibut steaks, garbanzo beans, lima beans, soybeans, and spinach]] 
Spices, nuts, cereals, cocoa and vegetables are good sources of magnesium.<ref name="nih">{{cite web|url=https://ods.od.nih.gov/factsheets/magnesium-HealthProfessional/|title = Dietary Supplement Fact Sheet: Magnesium| publisher = Office of Dietary Supplements, US National Institutes of Health|date=11 February 2016|access-date=13 October 2016}}</ref> Green leafy vegetables such as spinach are also rich in magnesium.<ref name="mlp">{{cite web |url=https://medlineplus.gov/ency/article/002423.htm | title=Magnesium in diet | publisher=MedlinePlus, U.S. National Library of Medicine, National Institutes of Health | date=2 February 2016 | access-date=13 October 2016}}</ref>

====Dietary recommendations ====
In the [[United Kingdom|UK]], the recommended daily values by the [[Dietary Reference Intake]] for magnesium are {{val|300|u=mg}} for men and {{val|270|u=mg}} for women.<ref>{{cite web |url=http://www.nhs.uk/Conditions/vitamins-minerals/Pages/Other-vitamins-minerals.aspx |title=Vitamins and minerals – Others – NHS Choices |publisher=Nhs.uk |date=26 November 2012 |access-date=19 September 2013 |archive-date=7 April 2011 |archive-url=https://web.archive.org/web/20110407015806/http://www.nhs.uk/Conditions/vitamins-minerals/Pages/Other-vitamins-minerals.aspx |url-status=dead }}</ref>

In the U.S. the [[Recommended Dietary Allowances]] (RDAs) are {{val|400|u=mg}} for men ages 19–30 and {{val|420|u=mg}} for older; for women {{val|310|u=mg}} for ages 19–30 and {{val|320|u=mg}} for older.<ref>{{cite book |chapter-url=https://www.ncbi.nlm.nih.gov/books/NBK109816/ |chapter=6, Magnesium |pages=190–249 |title=Dietary Reference Intakes for Calcium, Phosphorus, Magnesium, Vitamin D, and Fluoride |publisher=National Academy Press |year=1997}}</ref>

====Supplementation====
Numerous [[Magnesium (pharmaceutical preparation)|pharmaceutical preparations of magnesium]] and [[dietary supplement]]s are available. Most people get enough magnesium through a [[healthy diet]], though supplements may help in specific conditions like magnesium deficiency, pregnancy complications, or certain chronic health issues.<ref>{{Cite web |last=MD |first=Robert H. Shmerling |date=3 June 2025 |title=What can magnesium do for you and how much do you need? |url=https://www.health.harvard.edu/blog/what-can-magnesium-do-for-you-and-how-much-do-you-need-202506033100 |access-date=15 June 2025 |website=Harvard Health |language=en}}</ref>

A 2014 [[literature review]] found limited evidence supporting oral magnesium supplementation for [[migraine]] prevention, suggesting that increasing dietary magnesium intake may be a more effective option for patients open to lifestyle changes.<ref name="migraine" />

===Metabolism===
An adult body contains {{val|22|–|26|u=grams}} of magnesium,<ref name="nih" /><ref>{{cite journal | pmid = 10727669 | volume=294 | title=Magnesium. An update on physiological, clinical and analytical aspects | date=April 2000 | pages=1–26 |issue=1–2 |vauthors=Saris NE, Mervaala E, Karppanen H, Khawaja JA, Lewenstam A |journal=Clin Chim Acta| doi=10.1016/S0009-8981(99)00258-2 }}</ref> with 60% in the [[skeleton]], 39% intracellular (20% in skeletal muscle), and 1% extracellular.<ref name="nih" /> Serum levels are typically {{val|0.7|–|1.0|u=mmol/L}} or {{val|1.8|–|2.4|u= [[Equivalent (chemistry)|mEq]]/L}}. Serum magnesium levels may be normal even when intracellular magnesium is deficient. The mechanisms for maintaining the magnesium level in the serum are varying [[Gastrointestinal tract|gastrointestinal]] absorption and [[renal]] excretion. Intracellular magnesium is correlated with intracellular [[potassium]]. Increased magnesium lowers [[calcium]]<ref name="ummedu">{{cite web|url=http://umm.edu/health/medical/altmed/supplement/magnesium|archive-url=https://web.archive.org/web/20170216071418/http://umm.edu/health/medical/altmed/supplement/magnesium|url-status=dead|archive-date=16 February 2017|title=Magnesium |publisher= University of Maryland Medical Center |website=Umm.edu |date=7 May 2013 |access-date=19 September 2013}}</ref> and can either prevent hypercalcemia or cause hypocalcemia depending on the initial level.<ref name="ummedu" /> Both low and high protein intake conditions inhibit magnesium absorption, as does the amount of [[phosphate]], [[phytate]], and [[fat]] in the gut. Unabsorbed dietary magnesium is excreted in feces; absorbed magnesium is excreted in urine and sweat.<ref name="Wester1987">{{cite journal |author=Wester PO |title=Magnesium |journal=Am. J. Clin. Nutr. |volume=45 |issue=5 Suppl |pages=1305–1312 |date=1987 |pmid=3578120|doi=10.1093/ajcn/45.5.1305 }}</ref>

=== Detection in serum and plasma ===
Magnesium status may be assessed by measuring serum and erythrocyte magnesium concentrations coupled with [[Urinary system|urinary]] and [[Feces|fecal]] magnesium content, but intravenous magnesium loading tests are more accurate and practical.<ref>{{cite journal |author=Arnaud MJ |title=Update on the assessment of magnesium status |journal=Br. J. Nutr. |volume=99 |pages=S24–S36 |date=2008|issue=Suppl 3 |pmid=18598586 |doi=10.1017/S000711450800682X |doi-access=free }}</ref> A retention of 20% or more of the injected amount indicates deficiency.<ref>{{cite journal |display-authors=6|author=Rob PM|author2=Dick K|author3=Bley N|author4=Seyfert T|author5=Brinckmann C|author6=Höllriegel V|author7=Friedrich HJ|author8=Dibbelt L|author9=Seelig MS|title=Can one really measure magnesium deficiency using the short-term magnesium loading test? |journal=J. Intern. Med. |volume=246 |issue=4 |pages=373–378 |date=1999 |pmid=10583708 |doi= 10.1046/j.1365-2796.1999.00580.x |s2cid=6734801|doi-access=free}}</ref> As of 2004, no [[biomarker]] has been established for magnesium.<ref>{{cite journal |author=Franz KB |title=A functional biological marker is needed for diagnosing magnesium deficiency |journal=J Am Coll Nutr |volume=23 |issue=6 |pages=738S–741S |date=2004|pmid=15637224 |doi=10.1080/07315724.2004.10719418|s2cid=37427458 }}</ref>

Magnesium concentrations in plasma or serum may be monitored for efficacy and safety in those receiving the drug [[Therapy|therapeutically]], to confirm the diagnosis in potential poisoning victims. The newborn children of mothers who received [[Parenteral nutrition|parenteral]] magnesium sulfate during labor may exhibit toxicity with normal serum magnesium levels.<ref>{{cite book |author=Baselt, R. |title=Disposition of Toxic Drugs and Chemicals in Man |publisher=Biomedical Publications |edition=8th |year=2008 |isbn=978-0962652370 |pages=875–877 }}</ref>

===Deficiency===
Low plasma magnesium ([[hypomagnesemia]]) is common: it is found in 2.5–15% of the general population.<ref name="Ayuk">{{cite journal |author1=Ayuk J. |author2=Gittoes N.J. | date = Mar 2014 | title = Contemporary view of the clinical relevance of magnesium homeostasis | journal = Annals of Clinical Biochemistry | volume = 51 | issue = 2| pages = 179–188 | doi = 10.1177/0004563213517628 |pmid=24402002 |s2cid=21441840 | doi-access = free }}</ref> From 2005 to 2006, 48 percent of the United States population consumed less magnesium than recommended in the [[Dietary Reference Intake]].<ref>{{cite journal |last1=Rosanoff |first1=Andrea |last2=Weaver |first2=Connie M |last3=Rude |first3=Robert K |title=Suboptimal magnesium status in the United States: are the health consequences underestimated? |journal=Nutrition Reviews |date=March 2012 |volume=70 |issue=3 |pages=153–164 |doi=10.1111/j.1753-4887.2011.00465.x |pmid=22364157 |url=http://www.nutritionalmagnesium.org/images/stories/pdf/Suboptimalmagnesium.pdf |archive-date=13 February 2021 |access-date=7 August 2018 |archive-url=https://web.archive.org/web/20210213220135/http://nutritionalmagnesium.org/images/stories/pdf/Suboptimalmagnesium.pdf |url-status=dead }}</ref> Other causes are increased renal or gastrointestinal loss, an increased intracellular shift, and proton-pump inhibitor antacid therapy. Most are asymptomatic, but symptoms referable to [[Neuromuscular medicine|neuromuscular]], [[Circulatory system|cardiovascular]], and metabolic dysfunction may occur.<ref name="Ayuk" /> [[Alcoholism]] is often associated with magnesium deficiency. Chronically low serum magnesium levels are associated with [[metabolic syndrome]], [[diabetes mellitus type 2]], [[fasciculation]], and hypertension.<ref name="Geiger2012">{{cite journal |author= Geiger H|author2= Wanner C |title= Magnesium in disease |journal= Clin Kidney J |volume=5 |issue= Suppl 1 |pages= i25–i38 |date=2012|doi= 10.1093/ndtplus/sfr165|pmid= 26069818 |pmc= 4455821 }}</ref>

===Therapy===
* Intravenous magnesium is recommended by the ACC/AHA/ESC 2006 Guidelines for Management of Patients With Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death for patients with ventricular [[Heart arrhythmia|arrhythmia]] associated with [[torsades de pointes]] who present with [[long QT syndrome]]; and for the treatment of patients with digoxin induced arrhythmias.<ref name="Zipes2006">{{cite journal |author= Zipes DP|author2= Camm AJ|author3= Borggrefe M|display-authors= etal |title= ACC/AHA/ESC 2006 Guidelines for Management of Patients With Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death: a report of the American College of Cardiology/American Heart Association Task Force and the European Society of Cardiology Committee for Practice Guidelines (writing committee to develop Guidelines for Management of Patients With Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death): developed in collaboration with the European Heart Rhythm Association and the Heart Rhythm Society |journal= Circulation |volume=114 |pages= e385–e484|date=2012 |doi= 10.1161/CIRCULATIONAHA.106.178233 |issue= 10 |pmid=16935995|doi-access= free }}</ref>
* Intravenous magnesium sulfate is used for the management of [[pre-eclampsia]] and [[eclampsia]].<ref name="James2010">{{cite journal |author= James MF |title= Magnesium in obstetrics |journal= Best Pract Res Clin Obstet Gynaecol |volume=24 |pages=327–337|date=2010 |doi=10.1016/j.bpobgyn.2009.11.004 |pmid= 20005782 |issue= 3}}</ref><ref name="Euser2009">{{Cite journal | last1 = Euser | first1 = A. G. | last2 = Cipolla | first2 = M. J. | doi = 10.1161/STROKEAHA.108.527788 | title = Magnesium Sulfate for the Treatment of Eclampsia: A Brief Review | journal = Stroke | volume = 40 | issue = 4 | pages = 1169–1175 | year = 2009 | pmid = 19211496| pmc =2663594 }}</ref>
* Hypomagnesemia, including that caused by alcoholism, is reversible by oral or parenteral magnesium administration depending on the degree of deficiency.<ref>{{cite book|author=Giannini, A. J.|title=Drugs of Abuse|edition=Second|location=Los Angeles|publisher=Physicians Management Information Co.|date=1997|isbn=978-0874894998}}</ref>
* There is limited evidence that magnesium supplementation may play a role in the prevention and treatment of [[migraine]].<ref name="migraine">{{cite journal |vauthors=Teigen L, Boes CJ |title=An evidence-based review of oral magnesium supplementation in the preventive treatment of migraine |journal=Cephalalgia |volume= 35|issue= 10|pages= 912–922|year=2014 |pmid=25533715 |doi=10.1177/0333102414564891 |s2cid=25398410 |type=Review |quote=There is a strong body of evidence demonstrating a relationship between magnesium status and migraine. Magnesium likely plays a role in migraine development at a biochemical level, but the role of oral magnesium supplementation in migraine prophylaxis and treatment remains to be fully elucidated. The strength of evidence supporting oral magnesium supplementation is limited at this time. }}</ref>

====Other medical applications====

Sorted by type of magnesium salt, other therapeutic applications include:

* [[Magnesium sulfate]], as the [[hydrate|heptahydrate]], also known as [[epsom salts]] from its source mineral, is used as bath salts, a laxative, and a highly soluble fertilizer.<ref>{{cite book |url=https://books.google.com/books?id=GP1caeWDUWkC&pg=PA224 | page=224 | title = The Fertilizer Encyclopedia | isbn = 978-0470431764 | last1 = Gowariker | first1 = Vasant | last2 = Krishnamurthy |first2=V. P. |first3=Sudha |last3=Gowariker |first4=Manik |last4=Dhanorkar |first5=Kalyani |last5=Paranjape | date = 8 April 2009| publisher=John Wiley & Sons }}</ref>
* [[Magnesium hydroxide]], suspended in water, is used in [[milk of magnesia]] antacids and laxatives.
* [[Magnesium chloride]], [[magnesium oxide|oxide]], [[magnesium gluconate|gluconate]], [[magnesium malate|malate]], [[magnesium orotate|orotate]], [[Magnesium glycinate|glycinate]], [[magnesium ascorbate|ascorbate]] and [[magnesium citrate|citrate]] are all used as oral magnesium supplements. 
* Magnesium [[borate]], [[magnesium salicylate|salicylate]], and [[magnesium sulfate|sulfate]] are used as [[antiseptic]]s.
* [[Magnesium stearate]] is a slightly flammable white powder with lubricating properties. In [[pharmacology|pharmaceutical]] technology, it is used in pharmacological manufacture to prevent [[Tablet (pharmacy)|tablets]] from sticking to the equipment while compressing the ingredients into tablet form.
* [[Magnesium carbonate]] powder is used by athletes such as gymnasts, weightlifters, and climbers to eliminate palm sweat, prevent sticking, and improve the grip on gymnastic apparatus, lifting bars, and climbing rocks.

===Overdose===
Overdose from dietary sources alone is unlikely because excess magnesium in the blood is promptly filtered by the [[kidney]]s. Overdose is more likely in the presence of impaired renal function.<ref name="Ayuk" />  Overdose is likely in cases of excessive intake of supplements. [[Megavitamin therapy]] has caused death in a child,<ref>{{cite journal |last1=McGuire |first1=John K. |last2=Kulkarni |first2=Mona Shah |last3=Baden |first3=Harris P. |title=Fatal Hypermagnesemia in a Child Treated with Megavitamin/Megamineral Therapy |journal=Pediatrics |date=1 February 2000 |volume=105 |issue=2 |pages=e18 |doi=10.1542/peds.105.2.e18 |pmid=10654978 }}</ref> and severe [[hypermagnesemia]] in a woman and a young girl who had healthy kidneys.<ref name="Kontani M, Hara A, Ohta S, Ikeda T 2005 448–452">{{cite journal |author=Kontani M|author2=Hara A|author3=Ohta S|author4= Ikeda T |title=Hypermagnesemia induced by massive cathartic ingestion in an elderly woman without pre-existing renal dysfunction |journal=Intern. Med. |volume=44 |issue=5 |pages=448–452 |date=2005 |pmid=15942092| doi = 10.2169/internalmedicine.44.448|doi-access=free |hdl=2297/16751 |hdl-access=free }}</ref><ref>{{cite journal|last1=Kutsal|first1=Ebru|last2=Aydemir|first2=Cumhur|last3=Eldes|first3=Nilufer|last4=Demirel|first4=Fatma|last5=Polat|first5=Recep|last6=Taspınar|first6=Ozan|last7=Kulah|first7=Eyup|title=Severe Hypermagnesemia as a Result of Excessive Cathartic Ingestion in a Child Without Renal Failure|journal=Pediatrics|date=February 2000|volume=205|issue=2|pages=570–572|doi=10.1097/PEC.0b013e31812eef1c|pmid=17726419}}</ref> The most common symptoms of overdose are nausea, vomiting, and diarrhea; other symptoms include [[hypotension]], confusion, slowed heart and [[Respiratory system|respiratory]] rates, deficiencies of other minerals, [[coma]], [[Cardiac arrhythmia/bradycardia|cardiac arrhythmia]], and death from [[cardiac arrest]].<ref name="ummedu" />

===Function in plants===
Plants require magnesium to synthesize [[chlorophyll]], essential for [[photosynthesis]].<ref>{{Cite web |title=Magnesium |url=https://www.tfi.org/sites/default/files/tfi-magnesium.pdf |access-date=14 July 2023 |publisher=The Fertilizer Institute |archive-date=18 March 2023 |archive-url=https://web.archive.org/web/20230318010641/https://www.tfi.org/sites/default/files/tfi-magnesium.pdf |url-status=dead }}</ref> Magnesium in the center of the [[porphyrin ring]] in chlorophyll functions in a manner similar to the iron in the center of the porphyrin ring in [[heme]]. [[Magnesium deficiency (plants)|Magnesium deficiency]] in plants causes late-season yellowing between leaf veins,<ref>{{Cite web |date=12 June 2023 |title=What Is the Connection between Chlorophyll and Magnesium? |url=http://www.allthingsnature.org/what-is-the-connection-between-chlorophyll-and-magnesium.htm |access-date=14 July 2023 |website=All Things Nature |language=en-US}}</ref> especially in older leaves, and can be corrected by either applying epsom salts (which is rapidly leached), or crushed dolomitic limestone, to the soil.

==Safety precautions==
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[[File:Burning Magnesium Block!.ogv|thumb|right|Magnesium block heated with blow torch to self-combustion, emitting intense white light|start=2:40|thumbtime=4:00]]

Magnesium metal and its alloys can be explosive hazards; they are highly flammable in their pure form when molten or in powder or ribbon form. Burning or molten magnesium reacts violently with water. When working with powdered magnesium, [[safety glasses]] with [[eye protection]] and UV filters (such as welders use) are employed because burning magnesium produces [[ultraviolet]] light that can permanently damage the [[retina]] of a human eye.<ref>{{cite web |url=http://www.edu.gov.mb.ca/k12/docs/support/scisafe/chapter8.html |title=Science Safety: Chapter 8 |publisher=Government of Manitoba |access-date=21 August 2007}}</ref>

Magnesium is capable of reducing [[water (molecule)|water]] and releasing highly flammable [[hydrogen]] gas:<ref>{{Greenwood&Earnshaw2nd}}</ref>

:Mg(s) + 2 {{chem|H|2|O}}(l) → [[Magnesium hydroxide|{{chem|Mg(OH)|2}}]](s) + {{chem|H|2}}(g)

Therefore, water cannot extinguish magnesium fires. The hydrogen gas produced intensifies the fire. Dry sand is an effective smothering agent, but only on relatively level and flat surfaces.

Magnesium reacts with [[carbon dioxide]] exothermically to form [[magnesium oxide]] and [[carbon]]:<ref name=CO2>{{multiref|{{cite web |url=http://chemed.chem.purdue.edu/demos/main_pages/9.8.html |title=The Reaction Between Magnesium and CO<sub>2</sub>|publisher=Purdue University|access-date=15 June 2016}}|{{cite video|first1=David|last1=Whisnant|first2=David|last2=Phillips|first3=Kelly|last3=Houston&nbsp;Jetzer|orig-date=6 March 2012|year=2022|title=Reaction of magnesium with carbon dioxide|url=https://www.chemedx.org/video/reaction-magnesium-carbon-dioxide|type=web video|publisher=American Chemical Society, Division of Chemical Education|via=ChemEdX}}}}</ref>

:2 Mg(s) + {{chem|CO|2}}(g) → 2 MgO(s) + C(s)

Hence, carbon dioxide fuels rather than extinguishes magnesium fires.

Burning magnesium can be quenched by using a [[Fire extinguisher#Class D dry powder and other agents for metal fires|Class D]] dry chemical fire extinguisher, or by covering the fire with [[sand]] or magnesium foundry flux to remove its air source.<ref>{{cite book |last=Cote |first=Arthur E. |date=2003 |title=Operation of Fire Protection Systems |publisher= Jones & Bartlett Learning |page=667 |isbn= 978-0877655848}}</ref>

== See also ==
* [[List of countries by magnesium production]]
* [[Magnesium oil]]

==Notes==
{{Notelist}}

== References ==
{{Reflist}}

==Cited sources==
*{{RubberBible99th}}

== External links ==
* [http://www.periodicvideos.com/videos/012.htm Magnesium] at ''[[The Periodic Table of Videos]]'' (University of Nottingham)
* [http://www.rsc.org/chemistryworld/podcast/element.asp Chemistry in its element podcast] (MP3) from the [[Royal Society of Chemistry]]'s [[Chemistry World]]: [http://www.rsc.org/images/CIIE_Magnesium_48kbps_tcm18-128524.mp3 Magnesium]
* {{cite journal |title=Magnesium – a versatile and often overlooked element: New perspectives with a focus on chronic kidney disease |journal=Clinical Kidney Journal |date=February 2012 |volume=5 |issue=Suppl 1 |pages=NP |doi=10.1093/ndtplus/sfs035 |pmid=26069823 |pmc=4455823 }}
* [[usgs.gov]]: [https://pubs.usgs.gov/periodicals/mcs2025/mcs2025.pdf#page=112 Magnesium compounds and Magnesium Metal] (Mineral Commodity Summaries 2025, p112-115)

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