Magnesium | Description, Properties, & Compounds

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class="md-content"> <div class="md-article-container template-desktop"> <div class="infinite-scroll-container article last"> <article class="article-content container-lg qa-content px-0 pt-0 pb-40 py-lg-20 content md-expanded" data-topic-id="356899"> <div class="grid gx-0"> <div class="col-auto"> <div class="topic-left-rail md-article-drawer position-relative d-flex border-right-sm border-left-sm open"> <div class="drawer d-flex flex-column open"> <div class="left-rail-section-content"> <div class="topic-left-rail-header text-truncate bg-gray-50 position-relative text-right d-flex align-items-center"> <div class="tlr-title px-20 py-15 text-left"> <em class="material-icons text-gray-400 d-lg-none" data-icon="toc"></em> <a class="font-serif font-weight-bold text-black link-blue" href="https://www.britannica.com/science/magnesium">magnesium</a> </div> <button aria-label="Close" class="js-sections-close-button btn-link btn-sm btn d-lg-none position-absolute top-0 p-10 right-0" > <em class="material-icons font-26" data-icon="close"></em> </button> </div> <div class="section-content pl-10 pr-20 pl-sm-50 pr-sm-60 pl-lg-5 pr-lg-10 pt-10 pt-lg-0 bg-gray-50 clear-catfish-ad"> <div class="toc mb-20"> <div class="font-serif font-14 font-weight-bold mx-15 mb-15 mt-20"> Table of Contents </div> <ul class="list-unstyled my-0" data-level="h1"><li data-target="#ref1"><div class="pl-25"><a class="link-gray-900 w-100" href="/science/magnesium">Introduction</a></div><div class="ml-40 toc-drawer sub-toc-drawer"></div></li><li data-target="#ref4445"><div class="d-flex align-items-center"><div class="ml-25"></div><a class="w-100 link-gray-900" href="/science/magnesium#ref4445">Occurrence, properties, and uses</a></div><div class="ml-40 toc-drawer sub-toc-drawer"></div></li><li data-target="#ref4446"><div class="d-flex align-items-center"><div class="ml-25"></div><a class="w-100 link-gray-900" href="/science/magnesium#ref4446">Principal compounds</a></div><div class="ml-40 toc-drawer sub-toc-drawer"></div></li></ul> <a class="toc-extra-link link-gray-900" href="https://www.britannica.com/science/magnesium/additional-info">References & Edit History</a> <a class="toc-extra-link link-gray-900" href="/facts/magnesium">Quick Facts & Related Topics</a> </div> <div class="tlr-media-slider pb-10 mb-30"> <a class="section-header link-gray-900 font-serif font-14 font-weight-bold mb-10 mx-10" href="https://www.britannica.com/science/magnesium/images-videos">Images</a> <div class="slider js-slider position-relative d-inline-flex align-items-center mw-100 "> <div class="slider-container js-slider-container overflow-hidden d-flex overflow-hidden text-nowrap ml-15"> <a href="https://cdn.britannica.com/88/22388-050-66BFFDB1/Magnesium-magnesium-symbol-square-Mg-properties-some.jpg" data-href="/media/1/356899/64455" class="media-overlay-link d-inline-block mr-5"> <img loading="lazy" 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Let us know if you have suggestions to improve this article (requires login). </div> <div class="type-menu"> <label for="feedback-type" class="label mb-10">Feedback Type</label> <select id="feedback-type" class="form-select mb-30" name="feedbackTypeId" required> <option value="" selected="selected">Select a type (Required)</option> <option value="1">Factual Correction</option> <option value="2">Spelling/Grammar Correction</option> <option value="3">Link Correction</option> <option value="4">Additional Information</option> <option value="5">Other</option> </select> </div> <label for="feedback" class="label mb-10">Your Feedback</label> <textarea id="feedback" class="form-control mb-30" name="feedback" maxlength="3000" rows="7" required></textarea> <button class="btn btn-blue" type="submit">Submit Feedback</button> </form> <div class="success-messaging d-none mt-30"> <div class="title">Thank you for your feedback</div> <p>Our editors will review what you’ve submitted and determine whether to revise the article.</p> </div> </div> </div> <div class="md-websites-modal size-lg d-none"> <div class="md-modal-body"> <div class="h2 font-serif pb-15 border-bottom font-weight-bold"> External Websites </div> <div class="pb-20"> <ul class="list-unstyled mt-20 lh-lg"> <li><a class="external" href="https://ods.od.nih.gov/factsheets/Magnesium-HealthProfessional" target="_blank" rel="noopener ">U.S. Department of Health & Human Services - National Institutes of Health - Magnesium</a></li> <li><a class="external" href="https://www.healthline.com/nutrition/magnesium-benefits" target="_blank" rel="noopener ">Healthline - 12 Evidence-Based Health Benefits of Magnesium</a></li> <li><a class="external" href="https://www.ncbi.nlm.nih.gov/books/NBK519036/" target="_blank" rel="noopener ">National Center for Biotechnology Information - Magnesium</a></li> <li><a class="external" href="https://cameochemicals.noaa.gov/chemical/6949" target="_blank" rel="noopener ">CAMEO Chemicals - Magnesium</a></li> <li><a class="external" href="https://www.lenntech.com/periodic/elements/mg.htm" target="_blank" rel="noopener ">Lenntech - Magnesium - Mg</a></li> <li><a class="external" href="https://lpi.oregonstate.edu/mic/minerals/magnesium" target="_blank" rel="noopener ">Oregon State University - Linus Pauling Institute - Magnesium</a></li> <li><a class="external" href="https://www.mountsinai.org/health-library/supplement/magnesium" target="_blank" rel="noopener ">Mount Sinai - Magnesium</a></li> <li><a class="external" href="https://www.webmd.com/vitamins/ai/ingredientmono-998/magnesium" target="_blank" rel="noopener ">WebMD - Magnesium - Uses, side effects, and more</a></li> <li><a class="external" href="https://www.rsc.org/periodic-table/element/12/magnesium" target="_blank" rel="noopener ">Royal Society of Chemistry - Magnesium</a></li> <li><a class="external" href="https://www.aafp.org/pubs/afp/issues/2009/0715/p157.html" target="_blank" rel="noopener ">American Academy of Family Physicians - Therapeutic Uses of Magnesium</a></li> <li><a class="external" href="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)" target="_blank" rel="noopener ">Chemistry LibreTexts - Chemistry of Magnesium</a></li> <li><a class="external" href="https://www.hsph.harvard.edu/nutritionsource/magnesium/" target="_blank" rel="noopener ">Harvard T.H. Chan School of Public Health - Magnesium</a></li> </ul> </div> <div class="md-websites-ebk-title">Britannica Websites</div> <div class="md-websites-ebk-subtitle">Articles from Britannica Encyclopedias for elementary and high school students.</div> <ul class="list-unstyled bps-topic-web-sites lh-lg"> <li><a class="external" href="https://kids.britannica.com/kids/article/magnesium/353410" target="_blank" rel="noopener">magnesium - Children's Encyclopedia (Ages 8-11)</a></li> <li><a class="external" href="https://kids.britannica.com/students/article/magnesium/275611" target="_blank" rel="noopener">magnesium - Student Encyclopedia (Ages 11 and up)</a></li> </ul> </div> </div> </div> </div> <div class="toc-header-marker"></div> <button class="ai-ask-button btn border-2 js-header-ai-ask-button d-none btn-sm btn-outline-red-400 border-red-400 mr-0 mr-lg-10 ml-5 ml-sm-10 ml-lg-0 p-10"> Ask the Chatbot a Question </button> <div class="caption alternate-titles">Also known as: Mg</div> <div class="md-byline module-spacing "> <div class="font-serif font-12"> <span class="written-by text-gray-700"> Written by </span> <div class="editor-popover popover p-0"> <a class="d-block p-20 gtm-byline font-12 byline-contributor" href="/contributor/Timothy-P-Hanusa/9263015" > <div class="editor-title font-16 font-weight-bold">Timothy P. Hanusa</div> <div class="editor-description font-12 font-serif mt-5 clamp-description text-black">Professor, Department of Chemistry, Vanderbilt University, Nashville, Tennessee.</div> </a> <div data-popper-arrow></div> </div> <span class="btn btn-link editor-link p-0 qa-byline-link gtm-byline font-12 byline-contributor text-decoration-underline"> Timothy P. Hanusa</span></div> <div class="font-serif font-12 text-gray-700"> <span class="qa-fact-checked-by">Fact-checked by</span> <div class="editor-popover popover p-0"> <a class="d-block p-20 font-12" href="/editor/The-Editors-of-Encyclopaedia-Britannica/4419" > <div class="editor-title font-16 font-weight-bold">The Editors of Encyclopaedia Britannica</div> <div class="editor-description font-12 font-serif mt-5 text-black">Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree. They write new content and verify and edit content received from contributors.</div> </a> <div data-popper-arrow></div> </div> <span class="btn btn-link editor-link p-0 qa-byline-link font-12 "> The Editors of Encyclopaedia Britannica</span></div> <div class="last-updated font-12 font-serif"> <span class="text-gray-700"> Last Updated: <time datetime="2024-10-24T00:00:00CDT" >Oct 24, 2024</time> •</span> <a class="byline-edit-history" href="https://www.britannica.com/science/magnesium/additional-info#history" rel="nofollow">Article History</a> </div></div> </div> <button class="d-flex d-lg-none btn btn-outline-blue border rounded-sm shadow-sm mobile-toc-button gtm-mobile-toc-inline-button d-none d-sm-block js-sections-inline-button module-spacing btn d-lg-none"> <em class="material-icons mr-5 ml-n10 my-n5 md-icon" data-icon="toc"></em> Table of Contents </button> <div class="d-flex d-sm-none flex-row"> <button class="d-flex d-lg-none btn btn-outline-blue border rounded-sm shadow-sm mobile-toc-button gtm-mobile-toc-inline-button js-sections-inline-button module-spacing"> <em class="material-icons mr-5 ml-n10 my-n5 md-icon" data-icon="toc"></em> Table of Contents </button> <button class="ai-ask-button btn border-2 ai-ask-button btn border-2 module-spacing btn-sm js-inline-ai-ask-button btn-outline-red-400 border-red-400 p-10 ml-5"> Ask the Chatbot a Question </button> </div> <div class="js-qf-module qf-module px-40 px-sm-20 py-15 mx-auto module-spacing font-14 bg-gray-50 rounded"> <div class="facts-list mt-10"> <div class=""> <div class="js-fact mb-10 line-clamp clamp-3"> <dl> <dt>Key People: </dt> <dd><a href="/biography/Sir-Humphry-Davy-Baronet" topicid="152896">Sir Humphry Davy</a></dd> <dd><a href="/biography/Johann-Wolfgang-Dobereiner" topicid="167249">Johann Wolfgang Döbereiner</a></dd> </dl> <button class="js-more-btn d-none btn btn-unstyled font-12 bg-gray-50" aria-label="Toggle more/less fact data"> <em class="js-content link-blue">(Show more)</em> </button> </div> </div> <div class=""> <div class="js-fact mb-10 line-clamp clamp-3"> <dl> <dt>Related Topics: </dt> <dd><a href="/science/chemical-element" topicid="108636">chemical element</a></dd> <dd><a href="/science/human-nutrition" topicid="422896">human nutrition</a></dd> <dd><a href="/technology/magnesium-processing" topicid="356969">magnesium processing</a></dd> <dd><a href="/science/magnesium-deficiency" topicid="356946">magnesium deficiency</a></dd> <dd><a href="/science/magnesite" topicid="356886">magnesite</a></dd> </dl> <button class="js-more-btn d-none btn btn-unstyled font-12 bg-gray-50" aria-label="Toggle more/less fact data"> <em class="js-content link-blue">(Show more)</em> </button> </div> <div class="text-center"> <a class="btn btn-sm btn-link p-0" href="/facts/magnesium"> See all related content </a> </div> </div> </div> </div><span class="marker before-article"></span><section data-level="1" id="ref1"><span class="marker PREMOD1 mod-inline"></span><p class="topic-paragraph"><strong><span id="ref268346"></span>magnesium (Mg)</strong>, <a href="https://www.britannica.com/science/chemical-element" class="md-crosslink " data-show-preview="true">chemical element</a>, one of the <a href="https://www.britannica.com/science/alkaline-earth-metal" class="md-crosslink " data-show-preview="true">alkaline-earth metals</a> of Group 2 (IIa) of the <a href="https://www.britannica.com/science/periodic-table" class="md-crosslink " data-show-preview="true">periodic table</a>, and the lightest structural <a href="https://www.britannica.com/science/metal-chemistry" class="md-crosslink " data-show-preview="true">metal</a>. Its <a class="md-dictionary-link md-dictionary-tt-off mw" data-term="compounds" href="https://www.merriam-webster.com/dictionary/compounds" data-type="MW">compounds</a> are widely used in <a href="https://www.britannica.com/technology/construction" class="md-crosslink " data-show-preview="true">construction</a> and <a href="https://www.britannica.com/science/medicine" class="md-crosslink " data-show-preview="true">medicine</a>, and magnesium is one of the elements essential to all cellular <a href="https://www.britannica.com/science/life" class="md-crosslink " data-show-preview="true">life</a>.</p><span class="marker MOD1 mod-inline"></span><div class="text-center pb-20"><div class="md-table-wrapper"><table class="md-element-table"><caption>Element Properties</caption><tbody><tr><th scope="row">atomic number</th><td>12</td></tr><tr><th scope="row">atomic weight</th><td>24.305 </td></tr><tr><th scope="row">melting point</th><td>650 °C (1,202 °F)</td></tr><tr><th scope="row">boiling point</th><td>1,090 °C (1,994 °F)</td></tr><tr><th scope="row">specific gravity</th><td>1.74 at 20° C (68 °F)</td></tr><tr><th scope="row">oxidation state</th><td>+2</td></tr><tr><th scope="row">electron configuration</th><td>1<em>s</em><sup>2</sup>2<em>s</em><sup>2</sup>2<em>p</em><sup>6</sup>3<em>s</em><sup>2</sup></td></tr></tbody></table></div></div></section> <span class="marker h2"></span><section data-level="1" id="ref4445"> <h2 class="h1">Occurrence, properties, and uses</h2> <span class="marker PREMOD2 mod-inline"></span><p class="topic-paragraph">Known originally through <a href="https://www.britannica.com/science/chemical-compound" class="md-crosslink " data-show-preview="true">compounds</a> such as Epsom salts (the sulfate), magnesia or magnesia alba (the oxide), and <a href="https://www.britannica.com/science/magnesite" class="md-crosslink " data-show-preview="true">magnesite</a> (the carbonate), the silvery white element itself does not occur free in nature. It was first isolated in 1808 by <span id="ref268347"></span><a href="https://www.britannica.com/biography/Sir-Humphry-Davy-Baronet" class="md-crosslink " data-show-preview="true">Sir Humphry Davy</a>, who evaporated the <a href="https://www.britannica.com/science/mercury-chemical-element" class="md-crosslink " data-show-preview="true">mercury</a> from a magnesium <a href="https://www.britannica.com/technology/amalgam" class="md-crosslink " data-show-preview="true">amalgam</a> made by <a href="https://www.britannica.com/science/electrolysis" class="md-crosslink " data-show-preview="true">electrolyzing</a> a mixture of moist magnesia and mercuric oxide. The name <em>magnesium</em> comes from Magnesia, a district of <a href="https://www.britannica.com/place/Thessaly" class="md-crosslink " data-show-preview="true">Thessaly</a> (Greece) where the <a href="https://www.britannica.com/science/mineral-chemical-compound" class="md-crosslink " data-show-preview="true">mineral</a> magnesia alba was first found.</p><span class="marker MOD2 mod-inline"></span> <span class="marker PREMOD3 mod-inline"></span><p class="topic-paragraph">Magnesium is the eighth most <a class="md-dictionary-link md-dictionary-tt-off eb" data-term="abundant" href="https://www.britannica.com/dictionary/abundant" data-type="EB">abundant</a> <a href="https://www.britannica.com/science/chemical-element" class="md-crosslink " data-show-preview="true">element</a> in <a href="https://www.britannica.com/place/Earth" class="md-crosslink " data-show-preview="true">Earth</a>’s crust (about 2.5 percent) and is, after <a href="https://www.britannica.com/science/aluminum" class="md-crosslink " data-show-preview="true">aluminum</a> and <a href="https://www.britannica.com/science/iron-chemical-element" class="md-crosslink " data-show-preview="true">iron</a>, the third most plentiful structural <a href="https://www.britannica.com/science/metal-chemistry" class="md-crosslink " data-show-preview="true">metal</a>. Its cosmic abundance is estimated as 9.1 × 10<sup>5</sup> <a href="https://www.britannica.com/science/atom" class="md-crosslink " data-show-preview="true">atoms</a> (on a scale where the abundance of <a href="https://www.britannica.com/science/silicon" class="md-crosslink " data-show-preview="true">silicon</a> = 10<sup>6</sup> atoms). It occurs as carbonates—<a href="https://www.britannica.com/science/magnesite" class="md-crosslink " data-show-preview="true">magnesite</a>, MgCO<sub>3</sub>, and <a href="https://www.britannica.com/science/dolomite-mineral" class="md-crosslink " data-show-preview="true">dolomite</a>, CaMg(CO<sub>3</sub>)<sub>2</sub>—and in many common silicates, including <a href="https://www.britannica.com/science/talc" class="md-crosslink " data-show-preview="true">talc</a>, <a href="https://www.britannica.com/science/olivine" class="md-crosslink " data-show-preview="true">olivine</a>, and most kinds of <a href="https://www.britannica.com/science/asbestos-mineral" class="md-crosslink " data-show-preview="true">asbestos</a>. It also is found as hydroxide (<a href="https://www.britannica.com/science/brucite" class="md-crosslink " data-show-preview="true">brucite</a>), chloride (<a href="https://www.britannica.com/science/carnallite" class="md-crosslink " data-show-preview="true">carnallite</a>, KMgCl<sub>3</sub>∙6H<sub>2</sub>O), and sulfate (<a href="https://www.britannica.com/science/kieserite" class="md-crosslink " data-show-preview="true">kieserite</a>). It is distributed in minerals such as <a href="https://www.britannica.com/science/serpentine-mineral" class="md-crosslink " data-show-preview="true">serpentine</a>, chrysolite, and meerschaum. <span id="ref1030679"></span><a href="https://www.britannica.com/science/seawater" class="md-crosslink " data-show-preview="true">Seawater</a> contains about 0.13 percent magnesium, mostly as the <a class="md-dictionary-link md-dictionary-tt-off eb" data-term="dissolved" href="https://www.britannica.com/dictionary/dissolved" data-type="EB">dissolved</a> chloride, which imparts its characteristic bitter taste.</p><a class="link-module shadow-sm d-block qa-quiz-module" href="/quiz/facts-you-should-know-the-periodic-table-quiz" data-link-module-iframe-link=""> <img loading="lazy" src="https://cdn.britannica.com/58/203458-131-D94E9327/periodic-table-concept.jpg" alt="Periodic Table of the elements concept image (chemistry)" class="rounded-sm mr-15" width="70" /> <div class="line-clamp clamp-5"> <div class="module-title bg-green">Britannica Quiz</div> <div class="font-weight-semi-bold mt-5">Facts You Should Know: The Periodic Table Quiz</div> </div> </a><span class="marker MOD3 mod-inline"></span> <span class="marker PREMOD4 mod-inline"></span><p class="topic-paragraph">Magnesium is commercially produced by <a href="https://www.britannica.com/science/electrolysis" class="md-crosslink autoxref " data-show-preview="true">electrolysis</a> of molten magnesium chloride (MgCl<sub>2</sub>), processed mainly from seawater and by the direct reduction of its compounds with suitable reducing agents—e.g., from the reaction of magnesium oxide or calcined dolomite with ferrosilicon (the Pidgeon process). (<em>See</em> <a href="https://www.britannica.com/technology/magnesium-processing" class="md-crosslink " data-show-preview="true">magnesium processing</a>.) </p><span class="marker MOD4 mod-inline"></span> <span class="marker PREMOD5 mod-inline"></span><p class="topic-paragraph">At one time, magnesium was used for photographic flash ribbon and powder, because in finely divided form it burns in <a href="https://www.britannica.com/science/air" class="md-crosslink " data-show-preview="true">air</a> with an intense white light; it still finds application in explosive and pyrotechnic devices. Because of its low <a href="https://www.britannica.com/science/density" class="md-crosslink " data-show-preview="true">density</a> (only two-thirds that of aluminum), it has found <a class="md-dictionary-link md-dictionary-tt-off eb" data-term="extensive" href="https://www.britannica.com/dictionary/extensive" data-type="EB">extensive</a> use in the <a href="https://www.britannica.com/technology/aerospace-industry" class="md-crosslink autoxref " data-show-preview="true">aerospace industry</a>. However, because the pure metal has low structural strength, magnesium is mainly used in the form of <a href="https://www.britannica.com/technology/alloy" class="md-crosslink " data-show-preview="true">alloys</a>—principally with 10 percent or less of aluminum, <a href="https://www.britannica.com/science/zinc" class="md-crosslink " data-show-preview="true">zinc</a>, and <a href="https://www.britannica.com/science/manganese" class="md-crosslink " data-show-preview="true">manganese</a>—to improve its hardness, <a href="https://www.britannica.com/science/tensile-strength" class="md-crosslink autoxref " data-show-preview="true">tensile strength</a>, and ability to be cast, welded, and machined. Casting, rolling, extruding, and forging techniques are all employed with the alloys, and further fabrication of the resulting sheet, <a href="https://www.britannica.com/technology/anode" class="md-crosslink autoxref " data-show-preview="true">plate</a>, or extrusion is carried out by normal forming, joining, and machining operations. Magnesium is the easiest structural metal to machine and has often been used when a large number of machining operations are required. Magnesium <a class="md-dictionary-link md-dictionary-tt-off eb" data-term="alloys" href="https://www.britannica.com/dictionary/alloys" data-type="EB">alloys</a> have a number of applications: they are used for parts of aircraft, spacecraft, machinery, <a href="https://www.britannica.com/technology/automobile" class="md-crosslink " data-show-preview="true">automobiles</a>, portable tools, and household appliances.</p><span class="marker MOD5 mod-inline"></span> <span class="marker PREMOD6 mod-inline"></span><p class="topic-paragraph">The thermal and electrical conductivity of magnesium and its <a href="https://www.britannica.com/science/melting-point" class="md-crosslink autoxref " data-show-preview="true">melting point</a> are very similar to those of aluminum. Whereas aluminum is attacked by <a href="https://www.britannica.com/science/alkali" class="md-crosslink " data-show-preview="true">alkalies</a> but is resistant to most <a href="https://www.britannica.com/science/acid" class="md-crosslink " data-show-preview="true">acids</a>, magnesium is resistant to most alkalies but is readily attacked by most acids to liberate <a href="https://www.britannica.com/science/hydrogen" class="md-crosslink " data-show-preview="true">hydrogen</a> (chromic and hydrofluoric acids are important exceptions). At normal <a href="https://www.britannica.com/science/temperature" class="md-crosslink " data-show-preview="true">temperatures</a> it is stable in air and <a href="https://www.britannica.com/science/water" class="md-crosslink " data-show-preview="true">water</a> because of the formation of a thin protective skin of oxide, but it is attacked by steam. Magnesium is a powerful reducing agent and is used to produce other metals from their compounds (e.g., <a href="https://www.britannica.com/science/titanium" class="md-crosslink " data-show-preview="true">titanium</a>, <a href="https://www.britannica.com/science/zirconium" class="md-crosslink " data-show-preview="true">zirconium</a>, and <a href="https://www.britannica.com/science/hafnium" class="md-crosslink " data-show-preview="true">hafnium</a>). It reacts directly with many elements.</p><span class="marker MOD6 mod-inline"></span> <span class="marker PREMOD7 mod-inline"></span><p class="topic-paragraph">Magnesium occurs in nature as a mixture of three <a href="https://www.britannica.com/science/isotope" class="md-crosslink " data-show-preview="true">isotopes</a>: magnesium-24 (79.0 percent), magnesium-26 (11.0 percent), and magnesium-25 (10.0 percent). Nineteen <a href="https://www.britannica.com/science/radioactive-isotope" class="md-crosslink " data-show-preview="true">radioactive isotopes</a> have been prepared; magnesium-28 has the longest <a href="https://www.britannica.com/science/half-life-radioactivity" class="md-crosslink " data-show-preview="true">half-life</a>, at 20.9 hours, and is a <a href="https://www.britannica.com/science/beta-particle" class="md-crosslink " data-show-preview="true">beta</a> emitter. Although magnesium-26 is not radioactive, it is the daughter nuclide of aluminum-26, which has a half-life of 7.2 × 10<sup>5</sup> years. Elevated levels of magnesium-26 have been found in some <a href="https://www.britannica.com/science/meteorite" class="md-crosslink " data-show-preview="true">meteorites</a>, and the ratio of magnesium-26 to magnesium-24 has been used in determining their age.</p><div class="module-spacing"> <DIV class="marketing-INLINE_SUBSCRIPTION marketing-content" data-marketing-id="INLINE_SUBSCRIPTION"><style> .student-promo-banner-wrapper { container-type: inline-size; margin-bottom: 15px; } @container (min-width: 475px) { .student-promo-banner { flex-direction: row; } .student-promo-banner-img-wrapper { margin-bottom: 0; margin-right: 10px; justify-content: flex-start; } .student-promo-banner-text-wrapper { text-align: left; margin-bottom: 0px; margin-left: 10px; } .student-promo-banner-button-wrapper { margin-right: 0; } }</style> <div class="student-promo-banner-wrapper"> <div class="student-promo-banner d-flex flex-column align-items-center bg-blue rounded p-20"> <div class="student-promo-banner-img-wrapper mb-20 mr-0 d-flex justify-content-center"> <img class="rounded" style="max-width: 100px; min-width: 80px" src="https://cdn.britannica.com/marketing/BlueThistle.webp" /> </div> <div class="student-promo-banner-text-wrapper ml-0 mb-10 text-center text-white"> <div class="h2 mb-10">Get Unlimited Access</div> <div class="h4 font-weight-semi-bold">Try Britannica Premium for free and discover more.</div> </div> <div class="student-promo-banner-button-wrapper d-flex justify-content-center align-items-center ml-auto mr-auto"> <a class="btn btn-m btn-orange" href="https://premium.britannica.com/premium-membership/?utm_source=premium&utm_medium=inline-cta&utm_campaign=black-friday-2024">Subscribe</a> </div> </div> </div> </DIV></div><span class="marker MOD7 mod-inline"></span> <span class="marker PREMOD8 mod-inline"></span><p class="topic-paragraph">The top producers of magnesium by the second decade of the 21st century included China, Russia, Turkey, and Austria.</p><span class="marker MOD8 mod-inline"></span> <div class="mb-20"><div class="w-100"><figure class="md-assembly m-0 mb-md-0 card card-borderless print-false" data-assembly-id="299687" data-asm-type="infogram"><div class="md-assembly-wrapper card-media " data-type="infogram"><script id="infogram_0__/z8pqlTWwRHqAnaNwFRkn" src="https://e.infogram.com/js/dist/embed.js?Itp" type="text/javascript" title="Explore an interactive periodic table of the elements"></script></div></figure></div></div> </section> <span class="marker h3"></span><section data-level="1" id="ref4446"> <h2 class="h1">Principal compounds</h2> <span class="marker PREMOD10 mod-inline"></span><div class="assemblies"><div class="w-100"><figure class="md-assembly m-0 mb-md-0 card card-borderless print-false" data-assembly-id="151686" data-asm-type="image"><div class="md-assembly-wrapper card-media " data-type="image"><a href="https://cdn.britannica.com/05/146905-050-ED124110/Magnesium-magnesium-Products-fire-starter-shavings-ribbon.jpg" class="gtm-assembly-link position-relative d-flex align-items-center justify-content-center media-overlay-link card-media" data-href="/media/1/356899/151686"><picture><source media="(min-width: 680px)" srcset="https://cdn.britannica.com/05/146905-050-ED124110/Magnesium-magnesium-Products-fire-starter-shavings-ribbon.jpg?w=300"><img src="https://cdn.britannica.com/05/146905-050-ED124110/Magnesium-magnesium-Products-fire-starter-shavings-ribbon.jpg?w=300" alt="magnesium processing" data-width="1600" data-height="1069" loading="eager"></picture><button class="magnifying-glass btn btn-circle position-absolute shadow btn-white top-10 right-10" aria-label="Zoom in"><em class="material-icons link-blue" data-icon="zoom_in"></em></button></a></div><figcaption class="card-body"><div class="md-assembly-caption text-muted font-14 font-serif line-clamp"><span><a class="gtm-assembly-link md-assembly-title font-weight-bold d-inline font-sans-serif mr-5 media-overlay-link" href="https://cdn.britannica.com/05/146905-050-ED124110/Magnesium-magnesium-Products-fire-starter-shavings-ribbon.jpg" data-href="/media/1/356899/151686">magnesium processing</a><span>Products made of magnesium: fire starter and shavings, sharpener, and magnesium ribbon.</span><button class="js-more-btn d-none btn btn-unstyled font-12 bg-white js-content" aria-label="Toggle more/less fact data"><span class="link-blue">(more)</span></button></span></div></figcaption></figure></div></div><p class="topic-paragraph">In <a href="https://www.britannica.com/science/chemical-compound" class="md-crosslink " data-show-preview="true">compounds</a>, magnesium virtually always exhibits a +2 <a href="https://www.britannica.com/science/oxidation-number" class="md-crosslink autoxref " data-show-preview="true">oxidation state</a> because of the loss or sharing of its two 3<em>s</em> <a href="https://www.britannica.com/science/electron" class="md-crosslink " data-show-preview="true">electrons</a>. There are, however, a small number of <a href="https://www.britannica.com/science/coordination-compound" class="md-crosslink " data-show-preview="true">coordination compounds</a> known with magnesium-magnesium bonds, LMg―MgL, in which the magnesium centres have a formal +1 oxidation state. <span id="ref268348"></span><a href="https://www.britannica.com/science/magnesium-carbonate" class="md-crosslink ">Magnesium carbonate</a>, MgCO<sub>3</sub>, occurs in nature as the <a href="https://www.britannica.com/science/mineral-chemical-compound" class="md-crosslink " data-show-preview="true">mineral</a> <a href="https://www.britannica.com/science/magnesite" class="md-crosslink " data-show-preview="true">magnesite</a> and is an important source of elemental magnesium. It can be produced artificially by the action of <a href="https://www.britannica.com/science/carbon-dioxide" class="md-crosslink " data-show-preview="true">carbon dioxide</a> on a variety of magnesium compounds. The odourless white powder has many industrial uses—e.g., as a heat insulator for boilers and pipes and as an additive in <a href="https://www.britannica.com/topic/food" class="md-crosslink autoxref " data-show-preview="true">food</a>, <a class="md-dictionary-link md-dictionary-tt-off eb" data-term="pharmaceuticals" href="https://www.britannica.com/dictionary/pharmaceuticals" data-type="EB">pharmaceuticals</a>, cosmetics, rubbers, inks, and <a href="https://www.britannica.com/technology/glass" class="md-crosslink autoxref " data-show-preview="true">glass</a>. As magnesium carbonate is both hygroscopic and insoluble in <a href="https://www.britannica.com/science/water" class="md-crosslink " data-show-preview="true">water</a>, it was the original additive used to make table <a href="https://www.britannica.com/science/salt" class="md-crosslink " data-show-preview="true">salt</a> free-flowing even in high-humidity conditions.</p><span class="marker MOD10 mod-inline"></span> <span class="marker PREMOD11 mod-inline"></span><p class="topic-paragraph"><span id="ref268349"></span><a href="https://www.britannica.com/science/magnesium-hydroxide" class="md-crosslink ">Magnesium hydroxide</a>, Mg(OH)<sub>2</sub>, is a white powder produced in large quantities from seawater by the addition of milk of lime (calcium hydroxide). It is the primary raw material in the production of magnesium <a href="https://www.britannica.com/science/metal-chemistry" class="md-crosslink " data-show-preview="true">metal</a> and has been used as a fire-retardant additive. In water it forms a suspension known as milk of magnesia, which has long been used as an <a href="https://www.britannica.com/science/antacid" class="md-crosslink autoxref " data-show-preview="true">antacid</a> and a <a href="https://www.britannica.com/science/laxative" class="md-crosslink autoxref " data-show-preview="true">laxative</a>.</p><span class="marker MOD11 mod-inline"></span> <span class="marker PREMOD12 mod-inline"></span><p class="topic-paragraph">The action of <a href="https://www.britannica.com/science/hydrochloric-acid" class="md-crosslink " data-show-preview="true">hydrochloric acid</a> on magnesium hydroxide produces <span id="ref268350"></span><a href="https://www.britannica.com/science/magnesium-chloride" class="md-crosslink ">magnesium chloride</a>, MgCl<sub>2</sub>, a colourless, deliquescent (water-absorbing) substance employed in magnesium metal production, in the manufacture of a <a href="https://www.britannica.com/technology/cement-building-material" class="md-crosslink " data-show-preview="true">cement</a> for heavy-duty flooring, and as an additive in <a href="https://www.britannica.com/topic/textile" class="md-crosslink " data-show-preview="true">textile</a> manufacture. It is also used to coagulate soy milk in the production of <a href="https://www.britannica.com/topic/tofu" class="md-crosslink " data-show-preview="true">tofu</a>.</p><span class="marker MOD12 mod-inline"></span> <span class="marker PREMOD13 mod-inline"></span><p class="topic-paragraph">Roasting either magnesium carbonate or magnesium hydroxide produces the <a href="https://www.britannica.com/science/oxygen" class="md-crosslink " data-show-preview="true">oxygen</a> <a class="md-dictionary-link md-dictionary-tt-off mw" data-term="compound" href="https://www.merriam-webster.com/dictionary/compound" data-type="MW">compound</a> <span id="ref268351"></span><a href="https://www.britannica.com/science/magnesium-oxide" class="md-crosslink ">magnesium oxide</a>, commonly called magnesia, MgO. It is a white <a href="https://www.britannica.com/science/solid-state-of-matter" class="md-crosslink autoxref " data-show-preview="true">solid</a> used in the manufacture of high-temperature <a href="https://www.britannica.com/technology/refractory" class="md-crosslink autoxref " data-show-preview="true">refractory</a> bricks, electrical and thermal insulators, cements, <a href="https://www.britannica.com/topic/fertilizer" class="md-crosslink " data-show-preview="true">fertilizer</a>, <a href="https://www.britannica.com/science/rubber-chemical-compound" class="md-crosslink " data-show-preview="true">rubber</a>, and <a href="https://www.britannica.com/science/plastic" class="md-crosslink " data-show-preview="true">plastics</a>. It is also used medically as a laxative and antacid.</p><span class="marker MOD13 mod-inline"></span> <span class="marker PREMOD14 mod-inline"></span><p class="topic-paragraph"><span id="ref268352"></span><a href="https://www.britannica.com/science/magnesium-sulfate" class="md-crosslink ">Magnesium sulfate</a>, MgSO<sub>4</sub>, is a colourless crystalline substance formed by the reaction of magnesium hydroxide with <a href="https://www.britannica.com/science/sulfur-dioxide" class="md-crosslink " data-show-preview="true">sulfur dioxide</a> and air. A <a href="https://www.britannica.com/science/hydrate" class="md-crosslink autoxref " data-show-preview="true">hydrate</a> form of magnesium sulfate called <span id="ref137377"></span><a href="https://www.britannica.com/science/kieserite" class="md-crosslink " data-show-preview="true">kieserite</a>, MgSO<sub>4</sub>∙H<sub>2</sub>O, occurs as a <a href="https://www.britannica.com/science/mineral-deposit" class="md-crosslink autoxref " data-show-preview="true">mineral deposit</a>. Synthetically prepared magnesium sulfate is sold as Epsom <a href="https://www.britannica.com/science/salt-acid-base-reactions" class="md-crosslink autoxref " data-show-preview="true">salt</a>, MgSO<sub>4</sub>∙7H<sub>2</sub>O. In industry, magnesium sulfate is used in the manufacture of cements and fertilizers and in tanning and dyeing; in medicine it serves as a purgative. Because of its ability to absorb water readily, the anhydrous form is used as a desiccant (drying agent).</p><span class="marker MOD14 mod-inline"></span> <span class="marker PREMOD15 mod-inline"></span><p class="topic-paragraph">Among the <a href="https://www.britannica.com/science/organometallic-compound" class="md-crosslink " data-show-preview="true">organometallic compounds</a> of magnesium are the important <span id="ref137378"></span><a href="https://www.britannica.com/science/Grignard-reagent" class="md-crosslink " data-show-preview="true">Grignard reagents</a>, composed of an organic <a href="https://www.britannica.com/science/group-periodic-table" class="md-crosslink autoxref " data-show-preview="true">group</a> (e.g., alkyls and aryls), a <a href="https://www.britannica.com/science/halogen" class="md-crosslink " data-show-preview="true">halogen</a> <a href="https://www.britannica.com/science/atom" class="md-crosslink " data-show-preview="true">atom</a> other than <a href="https://www.britannica.com/science/fluorine" class="md-crosslink " data-show-preview="true">fluorine</a>, and magnesium. These are used in the production of many other kinds of organic and organometallic compounds.</p><div class="one-good-fact-module"> </div><span class="marker MOD15 mod-inline"></span> <span class="marker PREMOD16 mod-inline"></span><p class="topic-paragraph">Magnesium is essential to all living <a href="https://www.britannica.com/science/cell-biology" class="md-crosslink " data-show-preview="true">cells</a>, as the Mg<sup>2+</sup> ion is involved with the critically important biological polyphosphate compounds <a href="https://www.britannica.com/science/DNA" class="md-crosslink " data-show-preview="true">DNA</a>, <a href="https://www.britannica.com/science/RNA" class="md-crosslink " data-show-preview="true">RNA</a>, and <a href="https://www.britannica.com/science/adenosine-triphosphate" class="md-crosslink " data-show-preview="true">adenosine triphosphate</a> (ATP). Many <a href="https://www.britannica.com/science/enzyme" class="md-crosslink " data-show-preview="true">enzymes</a> depend on magnesium for their functioning. About one-sixth as plentiful as <a href="https://www.britannica.com/science/potassium" class="md-crosslink " data-show-preview="true">potassium</a> in <a href="https://www.britannica.com/science/human-body" class="md-crosslink autoxref " data-show-preview="true">human body</a> cells, magnesium is required as a <a href="https://www.britannica.com/science/catalyst" class="md-crosslink " data-show-preview="true">catalyst</a> for <a href="https://www.britannica.com/science/enzyme" class="md-crosslink autoxref " data-show-preview="true">enzyme</a> reactions in <a href="https://www.britannica.com/science/carbohydrate" class="md-crosslink " data-show-preview="true">carbohydrate</a> <a href="https://www.britannica.com/science/metabolism" class="md-crosslink " data-show-preview="true">metabolism</a>. Magnesium also is an essential <a class="md-dictionary-link md-dictionary-tt-off mw" data-term="constituent" href="https://www.merriam-webster.com/dictionary/constituent" data-type="MW">constituent</a> of the green pigment <a href="https://www.britannica.com/science/chlorophyll" class="md-crosslink " data-show-preview="true">chlorophyll</a>, found in virtually all <a href="https://www.britannica.com/plant/plant" class="md-crosslink " data-show-preview="true">plants</a>, <a href="https://www.britannica.com/science/algae" class="md-crosslink " data-show-preview="true">algae</a>, and <a href="https://www.britannica.com/science/blue-green-algae" class="md-crosslink " data-show-preview="true">cyanobacteria</a>. The <span id="ref1030680"></span><a href="https://www.britannica.com/science/photosynthesis" class="md-crosslink " data-show-preview="true">photosynthetic</a> function of plants depends upon the action of chlorophyll <a href="https://www.britannica.com/technology/pigment" class="md-crosslink " data-show-preview="true">pigments</a>, which contain magnesium at the centre of a complex, <a href="https://www.britannica.com/science/nitrogen" class="md-crosslink " data-show-preview="true">nitrogen</a>-containing <a href="https://www.britannica.com/science/ring-system" class="md-crosslink autoxref " data-show-preview="true">ring system</a> (<a href="https://www.britannica.com/science/porphyrin" class="md-crosslink " data-show-preview="true">porphyrin</a>). These magnesium compounds enable <a href="https://www.britannica.com/science/light" class="md-crosslink " data-show-preview="true">light</a> energy to drive the conversion of <a href="https://www.britannica.com/science/carbon-dioxide" class="md-crosslink " data-show-preview="true">carbon dioxide</a> and water to carbohydrates and oxygen and thus directly or indirectly provide the key to nearly all living processes.</p><span class="marker MOD16 mod-inline"></span> <span class="md-signature"><a href="/contributor/Timothy-P-Hanusa/9263015">Timothy P. 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Magnesium | Description, Properties, & Compounds | Britannica