Magnesium
Encyclopedia
Magnesium is a chemical element
with the symbol Mg, atomic number
12, and common oxidation number +2. It is an alkaline earth metal
and the eighth most abundant element
in the Earth's crust and ninth in the known universe
as a whole. Magnesium is the fourth most common element in the Earth as a whole (behind iron, oxygen and silicon), making up 13% of the planet's mass and a large fraction of planet's mantle. The relative abundance of magnesium is related to the fact that it is easily built up in supernova
stars from a sequential addition of three helium nuclei to carbon (which in turn is made from three helium nuclei). Due to magnesium ion's high solubility
in water, it is the third most abundant element dissolved in seawater
.
The free element (metal) is not found naturally on Earth, as it is highly reactive (though once produced, it is coated in a thin layer of oxide [see passivation
], which partly masks this reactivity). The free metal burns with a characteristic brilliant white light, making it a useful ingredient in flares. The metal is now mainly obtained by electrolysis
of magnesium salts obtained from brine
. Commercially, the chief use for the metal is as an alloy
ing agent to make aluminium
-magnesium alloys, sometimes called "magnalium
" or "magnelium". Since magnesium is less dense than aluminium, these alloys are prized for their relative lightness and strength.
Magnesium ions are sour to the taste, and in low concentrations help to impart a natural tartness to fresh mineral water
s.
Magnesium is the 11th most abundant element by mass in the human body
; its ions are essential to all living cells
, where they play a major role in manipulating important biological polyphosphate
compounds like ATP
, DNA
, and RNA
. Hundreds of enzyme
s thus require magnesium ions to function. Magnesium is also the metallic ion at the center of chlorophyll
, and is thus a common additive to fertilizer
s. Magnesium compounds are used medicinally as common laxative
s, antacids (e.g., milk of magnesia), and in a number of situations where stabilization of abnormal nerve
excitation and blood vessel spasm is required (e.g., to treat eclampsia
).
es slightly when exposed to air, although unlike the alkali metal
s, storage in an oxygen-free environment is unnecessary because magnesium is protected by a thin layer of oxide that is fairly impermeable and difficult to remove. Like its lower periodic table group
neighbor calcium
, magnesium reacts with water at room temperature, though it reacts much more slowly than calcium. When submerged in water, hydrogen
bubbles will almost unnoticeably begin to form on the surface of the metal, though if powdered it will react much more rapidly. The reaction will occur faster with higher temperatures (see precautions). Magnesium's ability to react with water can be harnessed to produce energy and run a magnesium-based engine
. Magnesium also reacts exothermically with most acids, such as hydrochloric acid
(HCl). As with aluminium, zinc and many other metals, the reaction with hydrochloric acid produces the chloride of the metal and releases hydrogen gas.
Magnesium is a highly flammable
metal, but while it is easy to ignite when powdered or shaved into thin strips, it is difficult to ignite in mass or bulk. Once ignited, it is difficult to extinguish, being able to burn in nitrogen
(forming magnesium nitride
), carbon dioxide
(forming magnesium oxide
and carbon
) and water (forming magnesium oxide and hydrogen). This property was used in incendiary weapons used in the firebombing
of cities in World War II
, the only practical civil defense
being to smother a burning flare under dry sand to exclude the atmosphere. On burning in air, magnesium produces a brilliant white light which includes strong ultraviolet. Thus magnesium powder (flash powder
) was used as a source of illumination in the early days of photography
. Later, magnesium ribbon was used in electrically ignited flash bulbs. Magnesium powder is used in the manufacture of fireworks
and marine flares
where a brilliant white light is required. Flame temperatures of magnesium and magnesium alloys can reach 3100 °C (3,373.2 K; 5,612 °F), although flame height above the burning metal is usually less than 300 mm (11.8 in). Magnesium may be used as an ignition source for thermite
, an otherwise difficult to ignite mixture of aluminium and iron oxide powder.
Magnesium compounds are typically white crystals. Most are soluble in water, providing the sour-tasting magnesium ion Mg2+. Small amounts of dissolved magnesium ion contribute to the tartness and taste of natural waters. Magnesium ion in large amounts is an ionic laxative, and magnesium sulfate
(common name: Epsom salt) is sometimes used for this purpose. So-called "milk of magnesia" is a water suspension of one of the few insoluble magnesium compounds, magnesium hydroxide
. The undissolved particles give rise to its appearance and name. Milk of magnesia is a mild base
commonly used as an antacid
, which has some laxative side effect.
s: 24Mg, 25Mg and 26Mg. All are present in significant amounts (see table of isotopes above). About 79% of Mg is 24Mg. The isotope 28Mg is radioactive and in the 1950s to 1970s was made commercially by several nuclear power plants for use in scientific experiments. This isotope has a relatively short half-life (21 hours) and so its use was limited by shipping times.
26Mg has found application in isotopic
geology
, similar to that of aluminium. 26Mg is a radiogenic daughter product of 26Al, which has a half-life
of 717,000 years. Large enrichments of stable 26Mg have been observed in the Ca-Al-rich inclusions
of some carbonaceous chondrite
meteorite
s. The anomalous abundance of 26Mg is attributed to the decay of its parent 26Al in the inclusions. Therefore, the meteorite must have formed in the solar nebula
before the 26Al had decayed. Hence, these fragments are among the oldest objects in the solar system
and have preserved information about its early history.
It is conventional to plot 26Mg/24Mg against an Al/Mg ratio. In an isochron dating
plot, the Al/Mg ratio plotted is27Al/24Mg. The slope of the isochron has no age significance, but indicates the initial 26Al/27Al ratio in the sample at the time when the systems were separated from a common reservoir.
and neon
, in the so-called alpha process. Creation requires temperatures above 600 megakelvins and masses greater than 3 solar masses.
Although magnesium is found in over 60 mineral
s, only dolomite
, magnesite
, brucite
, carnallite
, talc
, and olivine
are of commercial importance.
The cation is the second most abundant cation in seawater (occurring at about 12% of the mass of sodium there), which makes seawater and sea-salt an attractive commercial source of Mg. To extract the magnesium, calcium hydroxide
is added to seawater
to form magnesium hydroxide
precipitate.
Magnesium hydroxide (brucite
) is insoluble in water so it can be filtered out, and reacted with hydrochloric acid
to obtain concentrated magnesium chloride
.
From magnesium chloride, electrolysis
produces magnesium.
In the United States
, magnesium is principally obtained by electrolysis
of fused magnesium chloride from brine
s, wells, and sea water. At the cathode
, the ion is reduced by two electron
s to magnesium metal:
At the anode
, each pair of ions is oxidized to chlorine
gas, releasing two electrons to complete the circuit:
The United States has traditionally been the major world supplier of this metal, supplying 45% of world production even as recently as 1995. Today, the US market share is at 7%, with a single domestic producer left, US Magnesium, a Renco Group
company in Utah
born from now-defunct Magcorp.
As of 2005, China
has taken over as the dominant supplier, pegged at 60% world market share, which increased from 4% in 1995. Unlike the above-described electrolytic
process, China is almost completely reliant on a different method of obtaining the metal from its ores, the silicothermic
Pidgeon process
(the reduction of the oxide at high temperatures with silicon).
word for a district in Thessaly
called Magnesia
. It is related to magnetite
and manganese
, which also originated from this area, and required differentiation as separate substances. See manganese
for this history.
Magnesium is the seventh most abundant element in the Earth's crust by mass or molarity. It is found in large deposits of magnesite
, dolomite
, and other mineral
s, and in mineral waters, where magnesium ion is soluble. In 1618, a farmer at Epsom in England attempted to give his cows water from a well there. 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 became known as Epsom salts
and its fame spread; it was eventually recognized to be hydrated magnesium sulfate, MgSO4.
The metal itself was first produced by Sir Humphry Davy
in England in 1808 using electrolysis of a mixture of magnesia and mercury oxide
. Antoine Bussy
prepared it in coherent form in 1831. Davy's first suggestion for a name was magnium, but the name magnesium is now used.
Magnesium is the third most commonly used structural metal, following iron
and aluminium. It has been called the lightest useful metal by The Periodic Table of Videos
.
The main applications of magnesium are, in order: component of aluminium alloys, in die-casting (alloyed with zinc
), to remove sulfur
in the production of iron and steel, the production of titanium
in the Kroll process
.
Magnesium, in its purest form, can be compared with aluminium, and is strong and light, so it is used in several high volume part manufacturing applications, including automotive and truck components. Specialty, high-grade car wheels of magnesium alloy are called "mag wheels", although the term is often more broadly misapplied to include aluminum wheels. In 1957, a Corvette
SS, designed for racing, was constructed with magnesium body panels. An earlier Mercedes-Benz
race car model, the Mercedes-Benz 300 SLR
, had a body made from Elektron
, a magnesium alloy; these cars ran (with successes) at Le Mans
, the Mille Miglia
, and other world-class race events in 1955 (though one was involved in the single worst accident in auto racing history
, in terms of human casualties, at the Le Mans race.) Porsche's all-out quest to decrease the weight of their race cars led to the use of magnesium frames in the famous 917/053 that won Le Mans in 1971, and still holds the absolute distance record. The 917/30 Can-Am car also featured a magnesium frame, helping it to make the most of its prodigious 1100–1500 hp. Volkswagen Group
has used magnesium in its engine components for many years. For a long time, Porsche
used magnesium alloy for its engine blocks due to the weight advantage. There is renewed interest in magnesium engine blocks, as featured in the 2006 BMW
325i and 330i models. The BMW engine uses an aluminium alloy insert for the cylinder walls and cooling jackets surrounded by a high-temperature magnesium alloy AJ62A. The application of magnesium AE44 alloy in the 2006 Corvette Z06 engine cradle has advanced the technology of designing robust automotive parts in magnesium. Both these alloys are recent developments in high-temperature low creep
magnesium alloys. Mitsubishi Motors also uses magnesium (branded magnesium alloy) for its paddle shifters. The general strategy for such alloys is to form intermetallic precipitates at the grain boundaries
, for example by adding mischmetal
or calcium
. New alloy development and lower costs, which are becoming competitive to aluminium, will further the number of automotive applications.
The second application field of magnesium is electronic devices. Because of low weight, good mechanical and electrical properties, magnesium is widely used for manufacturing of mobile phones, laptop computers, cameras, and other electronic components.
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
' for magnesium alloy. The term is still used today. Because of perceived hazards with magnesium parts in the event of fire, the application of magnesium in the commercial aerospace industry was generally restricted to engine related components. Currently the use of magnesium alloys in aerospace is increasing, mostly driven by the increasing importance of fuel economy and the need to reduce weight. The development and testing of new magnesium alloys continues, notably Elektron 21, which has successfully undergone extensive aerospace testing for suitability in engine, internal and airframe components. The European Community runs three R&D magnesium projects in the Aerospace priority of Six Framework Program.
), so magnesium salts are frequently included in various food
s, fertilizer
s (magnesium is a component of chlorophyll
), and culture media.
Magnesium compounds, primarily magnesium oxide
(MgO), are used as refractory
a material in furnace
linings for producing iron
, steel
, nonferrous metals, glass
and cement
. Magnesium oxide and other magnesium compounds are also used in the agricultural, chemical, and construction industries.
Magnesium reacted with an alkyl halide gives a Gringard reagent
, which is a very useful tool for preparing alcohols.
and magnesium ions, magnesium ions are essential to the basic nucleic acid
chemistry of life, and thus are essential to all cells of all known living organisms. Over 300 enzyme
s require the presence of magnesium ions for their catalytic action, including all enzymes utilizing or synthesizing ATP
, or those that use other nucleotides to synthesize DNA
and RNA
. ATP exists in cells normally as a chelate of ATP and a magnesium ion.
Plants have an additional use for magnesium in that chlorophyll
s are magnesium-centered porphyrin
s. Magnesium deficiency
in plants causes late-season yellowing between leaf veins, especially in older leaves, and can be corrected by applying Epsom salts (which is rapidly leached
), or else crushed dolomitic
limestone
to the soil.
Magnesium is a vital component of a healthy human diet. Human magnesium deficiency
(including conditions that show few overt symptoms) is relatively rare although only 32% of the United States meet the RDA-DRI; low levels of magnesium in the body has been associated with the development of a number of human illnesses such as asthma
, diabetes, and osteoporosis
.
Adult human bodies contain about 24 grams of magnesium, with 60% in the skeleton
, 39% intracellular (20% in skeletal muscle), and 1% extracellular. Serum levels are typically 0.7–1.0 mmol/L or 1.8–2.4 mEq/L. Serum magnesium levels may appear normal even in cases of underlying intracellular deficiency, although no known mechanism maintains a homeostatic level in the blood other than renal excretion of high blood levels.
Intracellular magnesium is correlated with intracellular potassium
. Magnesium is absorbed in the gastrointestinal tract, with more absorbed when status is lower. In humans, magnesium appears to facilitate calcium
absorption. Low and high protein intake inhibit magnesium absorption, and other factors such as phosphate
, phytate, and fat
affect absorption. Absorbed dietary magnesium is largely excreted through the urine, although most magnesium "administered orally" is excreted through the feces. Magnesium status may be assessed roughly through serum and erythrocyte Mg concentrations and urinary and fecal excretion, but intravenous magnesium loading tests are likely the most accurate and practical in most people. In these tests, magnesium is injected intravenously; a retention of 20% or more indicates deficiency. Other nutrient deficiencies are identified through biomarkers, but none are established for magnesium.
Spices, nuts, cereals, coffee, cocoa, tea, and vegetables are rich sources of magnesium. Green leafy vegetables such as spinach
are also rich in magnesium as they contain chlorophyll. Observations of reduced dietary magnesium intake in modern Western countries compared to earlier generations may be related to food refining and modern fertilizers that contain no magnesium.
Numerous magnesium dietary supplement
s are available. Magnesium oxide
, one of the most common because it has high magnesium content per weight, has been reported to be the least bioavailable
. Magnesium citrate
has been reported as more bioavailable than oxide or amino-acid chelate (glycinate) forms.
Excess magnesium in the blood is freely filtered at the kidneys, and for this reason it is difficult to overdose on magnesium from dietary sources alone. With supplements, overdose is possible, however, particularly in people with poor renal function; occasionally, with use of high cathartic doses of magnesium salts, severe hypermagnesemia
has been reported to occur even without renal dysfunction. Alcoholism can produce a magnesium deficiency, which is easily reversed by oral or parenteral administration, depending on the degree of deficiency.
Magnesium metal and its alloys are explosive hazards; they are highly flammable in their pure form when molten or in powder or ribbon form. Burning or molten magnesium metal reacts violently with water. When working with powdered magnesium, safety glasses with welding eye protection
are employed, because the bright white light produced by burning magnesium contains ultraviolet
light that can permanently damage the retina
s of the eyes.
Magnesium is capable of reducing water to the highly flammable hydrogen
gas:
As a result, water cannot be used to extinguish magnesium fires; the hydrogen gas produced will only intensify the fire. Dry sand is an effective smothering agent but is usable only on relatively level and flat surfaces.
Magnesium also reacts with carbon dioxide
to form magnesium oxide and carbon
:
Hence, carbon dioxide fire extinguishers cannot be used for extinguishing magnesium fires either.
Burning magnesium is usually quenched by using a Class D dry chemical fire extinguisher, or by covering the fire with sand
or magnesium foundry flux to remove its air source.
Chemical element
A chemical element is a pure chemical substance consisting of one type of atom distinguished by its atomic number, which is the number of protons in its nucleus. Familiar examples of elements include carbon, oxygen, aluminum, iron, copper, gold, mercury, and lead.As of November 2011, 118 elements...
with the symbol Mg, atomic number
Atomic number
In chemistry and physics, the atomic number is the number of protons found in the nucleus of an atom and therefore identical to the charge number of the nucleus. It is conventionally represented by the symbol Z. The atomic number uniquely identifies a chemical element...
12, and common oxidation number +2. It is an alkaline earth metal
Alkaline earth metal
The alkaline earth metals are a group in the periodic table. In the modern IUPAC nomenclature, the alkaline earth metals are called the group 2 elements. Previously, they were called the Group IIA elements . The alkaline earth metals contain beryllium , magnesium , calcium , strontium , barium and...
and the eighth most abundant element
Abundance of the chemical elements
The abundance of a chemical element measures how relatively common the element is, or how much of the element is present in a given environment by comparison to all other elements...
in the Earth's crust and ninth in the known universe
Universe
The Universe is commonly defined as the totality of everything that exists, including all matter and energy, the planets, stars, galaxies, and the contents of intergalactic space. Definitions and usage vary and similar terms include the cosmos, the world and nature...
as a whole. Magnesium is the fourth most common element in the Earth as a whole (behind iron, oxygen and silicon), making up 13% of the planet's mass and a large fraction of planet's mantle. The relative abundance of magnesium is related to the fact that it is easily built up in supernova
Supernova
A supernova is a stellar explosion that is more energetic than a nova. It is pronounced with the plural supernovae or supernovas. Supernovae are extremely luminous and cause a burst of radiation that often briefly outshines an entire galaxy, before fading from view over several weeks or months...
stars from a sequential addition of three helium nuclei to carbon (which in turn is made from three helium nuclei). Due to magnesium ion's high solubility
Solubility
Solubility is the property of a solid, liquid, or gaseous chemical substance called solute to dissolve in a solid, liquid, or gaseous solvent to form a homogeneous solution of the solute in the solvent. The solubility of a substance fundamentally depends on the used solvent as well as on...
in water, it is the third most abundant element dissolved in seawater
Seawater
Seawater is water from a sea or ocean. On average, seawater in the world's oceans has a salinity of about 3.5% . This means that every kilogram of seawater has approximately of dissolved salts . The average density of seawater at the ocean surface is 1.025 g/ml...
.
The free element (metal) is not found naturally on Earth, as it is highly reactive (though once produced, it is coated in a thin layer of oxide [see passivation
Passivation
Passivation is the process of making a material "passive", and thus less reactive with surrounding air, water, or other gases or liquids. The goal is to inhibit corrosion, whether for structural or cosmetic reasons. Passivation of metals is usually achieved by the deposition of a layer of oxide...
], which partly masks this reactivity). The free metal burns with a characteristic brilliant white light, making it a useful ingredient in flares. The metal is now mainly obtained by electrolysis
Electrolysis
In chemistry and manufacturing, electrolysis is a method of using a direct electric current to drive an otherwise non-spontaneous chemical reaction...
of magnesium salts obtained from brine
Brine
Brine is water, saturated or nearly saturated with salt .Brine is used to preserve vegetables, fruit, fish, and meat, in a process known as brining . Brine is also commonly used to age Halloumi and Feta cheeses, or for pickling foodstuffs, as a means of preserving them...
. Commercially, the chief use for the metal is as an alloy
Alloy
An alloy is a mixture or metallic solid solution composed of two or more elements. Complete solid solution alloys give single solid phase microstructure, while partial solutions give two or more phases that may or may not be homogeneous in distribution, depending on thermal history...
ing agent to make aluminium
Aluminium
Aluminium or aluminum is a silvery white member of the boron group of chemical elements. It has the symbol Al, and its atomic number is 13. It is not soluble in water under normal circumstances....
-magnesium alloys, sometimes called "magnalium
Magnalium
Magnalium is an aluminium alloy with 1.5 to 2% magnesium and small amounts of copper, nickel, and tin. Some alloys, intended for particular uses at the cost of poor corrosion resistance, may consist of up to 50% magnesium...
" or "magnelium". Since magnesium is less dense than aluminium, these alloys are prized for their relative lightness and strength.
Magnesium ions are sour to the taste, and in low concentrations help to impart a natural tartness to fresh mineral water
Mineral water
Mineral water is water containing minerals or other dissolved substances that alter its taste or give it therapeutic value, generally obtained from a naturally occurring mineral spring or source. Dissolved substances in the water may include various salts and sulfur compounds...
s.
Magnesium is the 11th most abundant element by mass in the human body
Human body
The human body is the entire structure of a human organism, and consists of a head, neck, torso, two arms and two legs.By the time the human reaches adulthood, the body consists of close to 100 trillion cells, the basic unit of life...
; its ions are essential to all living cells
Cell (biology)
The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of life that is classified as a living thing, and is often called the building block of life. The Alberts text discusses how the "cellular building blocks" move to shape developing embryos....
, where they play a major role in manipulating important biological polyphosphate
Polyphosphate
Triphosphates are salts or esters of polymeric oxyanions formed from tetrahedral PO4 structural units linked together by sharing oxygen atoms. When two corners are shared the polyphosphate may have a linear chain structure or a cyclic ring structure. In biology the polyphosphate esters AMP, ADP...
compounds like ATP
Adenosine triphosphate
Adenosine-5'-triphosphate is a multifunctional nucleoside triphosphate used in cells as a coenzyme. It is often called the "molecular unit of currency" of intracellular energy transfer. ATP transports chemical energy within cells for metabolism...
, DNA
DNA
Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms . The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in...
, and RNA
RNA
Ribonucleic acid , or RNA, is one of the three major macromolecules that are essential for all known forms of life....
. Hundreds of enzyme
Enzyme
Enzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates...
s thus require magnesium ions to function. Magnesium is also the metallic ion at the center of chlorophyll
Chlorophyll
Chlorophyll is a green pigment found in almost all plants, algae, and cyanobacteria. Its name is derived from the Greek words χλωρος, chloros and φύλλον, phyllon . Chlorophyll is an extremely important biomolecule, critical in photosynthesis, which allows plants to obtain energy from light...
, and is thus a common additive to fertilizer
Fertilizer
Fertilizer is any organic or inorganic material of natural or synthetic origin that is added to a soil to supply one or more plant nutrients essential to the growth of plants. A recent assessment found that about 40 to 60% of crop yields are attributable to commercial fertilizer use...
s. Magnesium compounds are used medicinally as common laxative
Laxative
Laxatives are foods, compounds, or drugs taken to induce bowel movements or to loosen the stool, most often taken to treat constipation. Certain stimulant, lubricant, and saline laxatives are used to evacuate the colon for rectal and/or bowel examinations, and may be supplemented by enemas under...
s, antacids (e.g., milk of magnesia), and in a number of situations where stabilization of abnormal nerve
Nerve
A peripheral nerve, or simply nerve, is an enclosed, cable-like bundle of peripheral axons . A nerve provides a common pathway for the electrochemical nerve impulses that are transmitted along each of the axons. Nerves are found only in the peripheral nervous system...
excitation and blood vessel spasm is required (e.g., to treat eclampsia
Eclampsia
Eclampsia , an acute and life-threatening complication of pregnancy, is characterized by the appearance of tonic-clonic seizures, usually in a patient who had developed pre-eclampsia...
).
Physical and chemical properties
Elemental magnesium is a fairly strong, silvery-white, light-weight metal (two thirds the density of aluminium). It tarnishTarnish
Tarnish is a thin layer of corrosion that forms over copper, brass, silver, aluminum, and other similar metals as their outermost layer undergoes a chemical reaction. Tarnish does not always result from the sole effects of oxygen in the air. For example, silver needs hydrogen sulfide to tarnish; it...
es slightly when exposed to air, although unlike the alkali metal
Alkali metal
The alkali metals are a series of chemical elements in the periodic table. In the modern IUPAC nomenclature, the alkali metals comprise the group 1 elements, along with hydrogen. The alkali metals are lithium , sodium , potassium , rubidium , caesium , and francium...
s, storage in an oxygen-free environment is unnecessary because magnesium is protected by a thin layer of oxide that is fairly impermeable and difficult to remove. Like its lower periodic table group
Periodic table group
In chemistry, a group is a vertical column in the periodic table of the chemical elements. There are 18 groups in the standard periodic table, including the d-block elements, but excluding the f-block elements....
neighbor calcium
Calcium
Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth-most-abundant element by mass in the Earth's crust...
, magnesium reacts with water at room temperature, though it reacts much more slowly than calcium. When submerged in water, hydrogen
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
bubbles will almost unnoticeably begin to form on the surface of the metal, though if powdered it will react much more rapidly. The reaction will occur faster with higher temperatures (see precautions). Magnesium's ability to react with water can be harnessed to produce energy and run a magnesium-based engine
Magnesium injection cycle
Magnesium Injection Cycle is an engine design currently under development by Mitsubishi Corporation and the Tokyo Institute of Technology which uses magnesium and water to generate power...
. Magnesium also reacts exothermically with most acids, such as hydrochloric acid
Hydrochloric acid
Hydrochloric acid is a solution of hydrogen chloride in water, that is a highly corrosive, strong mineral acid with many industrial uses. It is found naturally in gastric acid....
(HCl). As with aluminium, zinc and many other metals, the reaction with hydrochloric acid produces the chloride of the metal and releases hydrogen gas.
Magnesium is a highly flammable
Flammability
Flammability is defined as how easily something will burn or ignite, causing fire or combustion. The degree of difficulty required to cause the combustion of a substance is quantified through fire testing. Internationally, a variety of test protocols exist to quantify flammability...
metal, but while it is easy to ignite when powdered or shaved into thin strips, it is difficult to ignite in mass or bulk. Once ignited, it is difficult to extinguish, being able to burn in nitrogen
Nitrogen
Nitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere...
(forming magnesium nitride
Magnesium nitride
Magnesium nitride, which has the chemical formula Mg3N2, is an inorganic compound of magnesium and nitrogen. At room temperature and pressure it is a greenish yellow powder.-Chemistry:...
), carbon dioxide
Carbon dioxide
Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...
(forming magnesium oxide
Magnesium oxide
Magnesium oxide , or magnesia, is a white hygroscopic solid mineral that occurs naturally as periclase and is a source of magnesium . It has an empirical formula of and consists of a lattice of Mg2+ ions and O2– ions held together by ionic bonds...
and carbon
Carbon
Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...
) and water (forming magnesium oxide and hydrogen). This property was used in incendiary weapons used in the firebombing
Firebombing
Firebombing is a bombing technique designed to damage a target, generally an urban area, through the use of fire, caused by incendiary devices, rather than from the blast effect of large bombs....
of cities in World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
, the only practical civil defense
Civil defense
Civil defense, civil defence or civil protection is an effort to protect the citizens of a state from military attack. It uses the principles of emergency operations: prevention, mitigation, preparation, response, or emergency evacuation, and recovery...
being to smother a burning flare under dry sand to exclude the atmosphere. On burning in air, magnesium produces a brilliant white light which includes strong ultraviolet. Thus magnesium powder (flash powder
Flash powder
Flash powder is a pyrotechnic composition, a mixture of oxidizer and metallic fuel, which burns quickly and if confined produces a loud report. It is widely used in theatrical pyrotechnics and fireworks and was once used for flashes in photography.Different varieties of flash powder are made from...
) was used as a source of illumination in the early days of photography
Photography
Photography is the art, science and practice of creating durable images by recording light or other electromagnetic radiation, either electronically by means of an image sensor or chemically by means of a light-sensitive material such as photographic film...
. Later, magnesium ribbon was used in electrically ignited flash bulbs. Magnesium powder is used in the manufacture of fireworks
Fireworks
Fireworks are a class of explosive pyrotechnic devices used for aesthetic and entertainment purposes. The most common use of a firework is as part of a fireworks display. A fireworks event is a display of the effects produced by firework devices...
and marine flares
Flare (pyrotechnic)
A flare, also sometimes called a fusee, is a type of pyrotechnic that produces a brilliant light or intense heat without an explosion. Flares are used for signalling, illumination, or defensive countermeasures in civilian and military applications...
where a brilliant white light is required. Flame temperatures of magnesium and magnesium alloys can reach 3100 °C (3,373.2 K; 5,612 °F), although flame height above the burning metal is usually less than 300 mm (11.8 in). Magnesium may be used as an ignition source for thermite
Thermite
Thermite is a pyrotechnic composition of a metal powder and a metal oxide that produces an exothermic oxidation-reduction reaction known as a thermite reaction. If aluminium is the reducing agent it is called an aluminothermic reaction...
, an otherwise difficult to ignite mixture of aluminium and iron oxide powder.
Magnesium compounds are typically white crystals. Most are soluble in water, providing the sour-tasting magnesium ion Mg2+. Small amounts of dissolved magnesium ion contribute to the tartness and taste of natural waters. Magnesium ion in large amounts is an ionic laxative, and magnesium sulfate
Magnesium sulfate
Magnesium sulfate is a chemical compound containing magnesium, sulfur and oxygen, with the formula MgSO4. It is often encountered as the heptahydrate epsomite , commonly called Epsom salt, from the town of Epsom in Surrey, England, where the salt was distilled from the springs that arise where the...
(common name: Epsom salt) is sometimes used for this purpose. So-called "milk of magnesia" is a water suspension of one of the few insoluble magnesium compounds, magnesium hydroxide
Magnesium hydroxide
Magnesium hydroxide is an inorganic compound with the chemical formula Mg2. As a suspension in water, it is often called milk of magnesia because of its milk-like appearance. The solid mineral form of magnesium hydroxide is known as brucite....
. The undissolved particles give rise to its appearance and name. Milk of magnesia is a mild base
Base (chemistry)
For the term in genetics, see base A base in chemistry is a substance that can accept hydrogen ions or more generally, donate electron pairs. A soluble base is referred to as an alkali if it contains and releases hydroxide ions quantitatively...
commonly used as an antacid
Antacid
An antacid is a substance which neutralizes stomach acidity.-Mechanism of action:Antacids perform a neutralization reaction, increasing the pH to reduce acidity in the stomach. When gastric hydrochloric acid reaches the nerves in the gastrointestinal mucosa, they signal pain to the central nervous...
, which has some laxative side effect.
Isotopes
Magnesium has three stable isotopeIsotope
Isotopes are variants of atoms of a particular chemical element, which have differing numbers of neutrons. Atoms of a particular element by definition must contain the same number of protons but may have a distinct number of neutrons which differs from atom to atom, without changing the designation...
s: 24Mg, 25Mg and 26Mg. All are present in significant amounts (see table of isotopes above). About 79% of Mg is 24Mg. The isotope 28Mg is radioactive and in the 1950s to 1970s was made commercially by several nuclear power plants for use in scientific experiments. This isotope has a relatively short half-life (21 hours) and so its use was limited by shipping times.
26Mg has found application in isotopic
Isotope
Isotopes are variants of atoms of a particular chemical element, which have differing numbers of neutrons. Atoms of a particular element by definition must contain the same number of protons but may have a distinct number of neutrons which differs from atom to atom, without changing the designation...
geology
Geology
Geology is the science comprising the study of solid Earth, the rocks of which it is composed, and the processes by which it evolves. Geology gives insight into the history of the Earth, as it provides the primary evidence for plate tectonics, the evolutionary history of life, and past climates...
, similar to that of aluminium. 26Mg is a radiogenic daughter product of 26Al, which has a half-life
Half-life
Half-life, abbreviated t½, is the period of time it takes for the amount of a substance undergoing decay to decrease by half. The name was originally used to describe a characteristic of unstable atoms , but it may apply to any quantity which follows a set-rate decay.The original term, dating to...
of 717,000 years. Large enrichments of stable 26Mg have been observed in the Ca-Al-rich inclusions
Ca-Al-rich inclusions
A calcium-aluminium-rich inclusion or Ca-Al-rich Inclusion is a submillimeter to centimeter-sized light-colored calcium- and aluminium-rich inclusion found in carbonaceous chondrite meteorites...
of some carbonaceous chondrite
Carbonaceous chondrite
Carbonaceous chondrites or C chondrites are a class of chondritic meteorites comprising at least 7 known groups and many ungrouped meteorites. They include some of the most primitive known meteorites...
meteorite
Meteorite
A meteorite is a natural object originating in outer space that survives impact with the Earth's surface. Meteorites can be big or small. Most meteorites derive from small astronomical objects called meteoroids, but they are also sometimes produced by impacts of asteroids...
s. The anomalous abundance of 26Mg is attributed to the decay of its parent 26Al in the inclusions. Therefore, the meteorite must have formed in the solar nebula
Solar nebula
In cosmogony, the nebular hypothesis is the most widely accepted model explaining the formation and evolution of the Solar System. There is evidence that it was first proposed in 1734 by Emanuel Swedenborg. Originally applied only to our own Solar System, this method of planetary system formation...
before the 26Al had decayed. Hence, these fragments are among the oldest objects in the solar system
Solar System
The Solar System consists of the Sun and the astronomical objects gravitationally bound in orbit around it, all of which formed from the collapse of a giant molecular cloud approximately 4.6 billion years ago. The vast majority of the system's mass is in the Sun...
and have preserved information about its early history.
It is conventional to plot 26Mg/24Mg against an Al/Mg ratio. In an isochron dating
Isochron dating
Isochron dating is a common technique of radiometric dating and is applied to date certain events, such as crystallization, metamorphism, shock events, and differentiation of precursor melts, in the history of rocks...
plot, the Al/Mg ratio plotted is27Al/24Mg. The slope of the isochron has no age significance, but indicates the initial 26Al/27Al ratio in the sample at the time when the systems were separated from a common reservoir.
Creation
Stable forms of magnesium are produced in stars. It is made from fusing heliumHelium
Helium is the chemical element with atomic number 2 and an atomic weight of 4.002602, which is represented by the symbol He. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas that heads the noble gas group in the periodic table...
and neon
Neon
Neon is the chemical element that has the symbol Ne and an atomic number of 10. Although a very common element in the universe, it is rare on Earth. A colorless, inert noble gas under standard conditions, neon gives a distinct reddish-orange glow when used in either low-voltage neon glow lamps or...
, in the so-called alpha process. Creation requires temperatures above 600 megakelvins and masses greater than 3 solar masses.
Occurrence
| Country | 2010 production (tonne Tonne The tonne, known as the metric ton in the US , often put pleonastically as "metric tonne" to avoid confusion with ton, is a metric system unit of mass equal to 1000 kilograms. The tonne is not an International System of Units unit, but is accepted for use with the SI... s) |
|---|---|
| China | 650,000 |
| Russia | 40,000 |
| Israel | 30,000 |
| Kazakhstan | 20,000 |
| Brazil | 16,000 |
| Ukraine | 2,000 |
| Serbia | 2,000 |
Although magnesium is found in over 60 mineral
Mineral
A mineral is a naturally occurring solid chemical substance formed through biogeochemical processes, having characteristic chemical composition, highly ordered atomic structure, and specific physical properties. By comparison, a rock is an aggregate of minerals and/or mineraloids and does not...
s, only dolomite
Dolomite
Dolomite is a carbonate mineral composed of calcium magnesium carbonate CaMg2. The term is also used to describe the sedimentary carbonate rock dolostone....
, magnesite
Magnesite
Magnesite is magnesium carbonate, MgCO3. Iron substitutes for magnesium with a complete solution series with siderite, FeCO3. Calcium, manganese, cobalt, and nickel may also occur in small amounts...
, brucite
Brucite
Brucite is the mineral form of magnesium hydroxide, with the chemical formula Mg2. It is a common alteration product of periclase in marble; a low-temperature hydrothermal vein mineral in metamorphosed limestones and chlorite schists; and formed during serpentinization of dunites...
, carnallite
Carnallite
Carnallite is an evaporite mineral, a hydrated potassium magnesium chloride with formula: KMgCl3·6. It is variably colored yellow to white, reddish, and sometimes colorless or blue. It is usually massive to fibrous with rare pseudohexagonal orthorhombic crystals...
, talc
Talc
Talc is a mineral composed of hydrated magnesium silicate with the chemical formula H2Mg34 or Mg3Si4O102. In loose form, it is the widely-used substance known as talcum powder. It occurs as foliated to fibrous masses, its crystals being so rare as to be almost unknown...
, and olivine
Olivine
The mineral olivine is a magnesium iron silicate with the formula 2SiO4. It is a common mineral in the Earth's subsurface but weathers quickly on the surface....
are of commercial importance.
The cation is the second most abundant cation in seawater (occurring at about 12% of the mass of sodium there), which makes seawater and sea-salt an attractive commercial source of Mg. To extract the magnesium, calcium hydroxide
Calcium hydroxide
Calcium hydroxide, traditionally called slaked lime, is an inorganic compound with the chemical formula Ca2. It is a colourless crystal or white powder and is obtained when calcium oxide is mixed, or "slaked" with water. It has many names including hydrated lime, builders lime, slack lime, cal, or...
is added to seawater
Seawater
Seawater is water from a sea or ocean. On average, seawater in the world's oceans has a salinity of about 3.5% . This means that every kilogram of seawater has approximately of dissolved salts . The average density of seawater at the ocean surface is 1.025 g/ml...
to form magnesium hydroxide
Magnesium hydroxide
Magnesium hydroxide is an inorganic compound with the chemical formula Mg2. As a suspension in water, it is often called milk of magnesia because of its milk-like appearance. The solid mineral form of magnesium hydroxide is known as brucite....
precipitate.
- + → +
Magnesium hydroxide (brucite
Brucite
Brucite is the mineral form of magnesium hydroxide, with the chemical formula Mg2. It is a common alteration product of periclase in marble; a low-temperature hydrothermal vein mineral in metamorphosed limestones and chlorite schists; and formed during serpentinization of dunites...
) is insoluble in water so it can be filtered out, and reacted with hydrochloric acid
Hydrochloric acid
Hydrochloric acid is a solution of hydrogen chloride in water, that is a highly corrosive, strong mineral acid with many industrial uses. It is found naturally in gastric acid....
to obtain concentrated magnesium chloride
Magnesium chloride
Magnesium chloride is the name for the chemical compounds with the formulas MgCl2 and its various hydrates MgCl2x. These salts are typical ionic halides, being highly soluble in water. The hydrated magnesium chloride can be extracted from brine or sea water...
.
- + 2 HCl → + 2
From magnesium chloride, electrolysis
Electrolysis
In chemistry and manufacturing, electrolysis is a method of using a direct electric current to drive an otherwise non-spontaneous chemical reaction...
produces magnesium.
In the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
, magnesium is principally obtained by electrolysis
Electrolysis
In chemistry and manufacturing, electrolysis is a method of using a direct electric current to drive an otherwise non-spontaneous chemical reaction...
of fused magnesium chloride from brine
Brine
Brine is water, saturated or nearly saturated with salt .Brine is used to preserve vegetables, fruit, fish, and meat, in a process known as brining . Brine is also commonly used to age Halloumi and Feta cheeses, or for pickling foodstuffs, as a means of preserving them...
s, wells, and sea water. At the cathode
Cathode
A cathode is an electrode through which electric current flows out of a polarized electrical device. Mnemonic: CCD .Cathode polarity is not always negative...
, the ion is reduced by two electron
Electron
The electron is a subatomic particle with a negative elementary electric charge. It has no known components or substructure; in other words, it is generally thought to be an elementary particle. An electron has a mass that is approximately 1/1836 that of the proton...
s to magnesium metal:
- + 2 → Mg
At the anode
Anode
An anode is an electrode through which electric current flows into a polarized electrical device. Mnemonic: ACID ....
, each pair of ions is oxidized to chlorine
Chlorine
Chlorine is the chemical element with atomic number 17 and symbol Cl. It is the second lightest halogen, found in the periodic table in group 17. The element forms diatomic molecules under standard conditions, called dichlorine...
gas, releasing two electrons to complete the circuit:
- 2 → (g) + 2
The United States has traditionally been the major world supplier of this metal, supplying 45% of world production even as recently as 1995. Today, the US market share is at 7%, with a single domestic producer left, US Magnesium, a Renco Group
Renco Group
Renco Group is a New York City-based holding company controlled by Ira Rennert that invests in other companies across a range of industries.-History:...
company in Utah
Utah
Utah is a state in the Western United States. It was the 45th state to join the Union, on January 4, 1896. Approximately 80% of Utah's 2,763,885 people live along the Wasatch Front, centering on Salt Lake City. This leaves vast expanses of the state nearly uninhabited, making the population the...
born from now-defunct Magcorp.
As of 2005, China
People's Republic of China
China , officially the People's Republic of China , is the most populous country in the world, with over 1.3 billion citizens. Located in East Asia, the country covers approximately 9.6 million square kilometres...
has taken over as the dominant supplier, pegged at 60% world market share, which increased from 4% in 1995. Unlike the above-described electrolytic
Electrolyte
In chemistry, an electrolyte is any substance containing free ions that make the substance electrically conductive. The most typical electrolyte is an ionic solution, but molten electrolytes and solid electrolytes are also possible....
process, China is almost completely reliant on a different method of obtaining the metal from its ores, the silicothermic
Silicothermic reaction
Silicothermic reactions are thermic chemical reactions using silicon as the reducing agent at high temperature . The most prominent example is the Pidgeon process for reducing magnesium metal from ores. Other processes include the Bolzano process and the magnetherm process...
Pidgeon process
Pidgeon process
The Pidgeon process is one of the methods of magnesium metal production, via a silicothermic reduction. Practical production requires roughly 35-40 MWh/ton of metal produced, which is on par with the molten salt electrolytic methods of production, though above the 7 MWh/ton theoretical...
(the reduction of the oxide at high temperatures with silicon).
History
The name magnesium originates from the GreekAncient Greek
Ancient Greek is the stage of the Greek language in the periods spanning the times c. 9th–6th centuries BC, , c. 5th–4th centuries BC , and the c. 3rd century BC – 6th century AD of ancient Greece and the ancient world; being predated in the 2nd millennium BC by Mycenaean Greek...
word for a district in Thessaly
Thessaly
Thessaly is a traditional geographical region and an administrative region of Greece, comprising most of the ancient region of the same name. Before the Greek Dark Ages, Thessaly was known as Aeolia, and appears thus in Homer's Odyssey....
called Magnesia
Magnesia Prefecture
Magnesia Prefecture was one of the prefectures of Greece. Its capital was Volos. It was established in 1899 from the Larissa Prefecture. The prefecture was disbanded on 1 January 2011 by the Kallikratis programme, and split into the peripheral units of Magnesia and the Sporades.The toponym is...
. It is related to magnetite
Magnetite
Magnetite is a ferrimagnetic mineral with chemical formula Fe3O4, one of several iron oxides and a member of the spinel group. The chemical IUPAC name is iron oxide and the common chemical name is ferrous-ferric oxide. The formula for magnetite may also be written as FeO·Fe2O3, which is one part...
and manganese
Manganese
Manganese is a chemical element, designated by the symbol Mn. It has the atomic number 25. It is found as a free element in nature , and in many minerals...
, which also originated from this area, and required differentiation as separate substances. See manganese
Manganese
Manganese is a chemical element, designated by the symbol Mn. It has the atomic number 25. It is found as a free element in nature , and in many minerals...
for this history.
Magnesium is the seventh most abundant element in the Earth's crust by mass or molarity. It is found in large deposits of magnesite
Magnesite
Magnesite is magnesium carbonate, MgCO3. Iron substitutes for magnesium with a complete solution series with siderite, FeCO3. Calcium, manganese, cobalt, and nickel may also occur in small amounts...
, dolomite
Dolomite
Dolomite is a carbonate mineral composed of calcium magnesium carbonate CaMg2. The term is also used to describe the sedimentary carbonate rock dolostone....
, and other mineral
Mineral
A mineral is a naturally occurring solid chemical substance formed through biogeochemical processes, having characteristic chemical composition, highly ordered atomic structure, and specific physical properties. By comparison, a rock is an aggregate of minerals and/or mineraloids and does not...
s, and in mineral waters, where magnesium ion is soluble. In 1618, a farmer at Epsom in England attempted to give his cows water from a well there. 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 became known as Epsom salts
Magnesium sulfate
Magnesium sulfate is a chemical compound containing magnesium, sulfur and oxygen, with the formula MgSO4. It is often encountered as the heptahydrate epsomite , commonly called Epsom salt, from the town of Epsom in Surrey, England, where the salt was distilled from the springs that arise where the...
and its fame spread; it was eventually recognized to be hydrated magnesium sulfate, MgSO4.
The metal itself was first produced by Sir Humphry Davy
Humphry Davy
Sir Humphry Davy, 1st Baronet FRS MRIA was a British chemist and inventor. He is probably best remembered today for his discoveries of several alkali and alkaline earth metals, as well as contributions to the discoveries of the elemental nature of chlorine and iodine...
in England in 1808 using electrolysis of a mixture of magnesia and mercury oxide
Mercury oxide
Mercury oxide can refer to:* Mercury oxide , Hg2O* Mercury oxide , HgO...
. Antoine Bussy
Antoine Bussy
Antoine Alexandre Brutus Bussy was a French chemist who primarily studied bussays.Antoine Bussy entered the Ecole Polytechnique in 1813, and there followed the courses delivered by Pierre Robiquet, the great French chemist who was to make decisive breakthroughs in bio-chemistry Antoine Alexandre...
prepared it in coherent form in 1831. Davy's first suggestion for a name was magnium, but the name magnesium is now used.
As Metal
Iron
Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...
and aluminium. It has been called the lightest useful metal by The Periodic Table of Videos
The Periodic Table of Videos
The Periodic Table of Videos is a series of videos on YouTube produced by Brady Haran, a former BBC video journalist, featuring professor Martyn Poliakoff, known as The Professor, Peter Licence, Stephen Liddle, Debbie Kays, Neil Barnes, Sam Tang and others at the University of Nottingham. The...
.
The main applications of magnesium are, in order: component of aluminium alloys, in die-casting (alloyed with zinc
Zinc
Zinc , or spelter , is a metallic chemical element; it has the symbol Zn and atomic number 30. It is the first element in group 12 of the periodic table. Zinc is, in some respects, chemically similar to magnesium, because its ion is of similar size and its only common oxidation state is +2...
), to remove sulfur
Sulfur
Sulfur or sulphur is the chemical element with atomic number 16. In the periodic table it is represented by the symbol S. It is an abundant, multivalent non-metal. Under normal conditions, sulfur atoms form cyclic octatomic molecules with chemical formula S8. Elemental sulfur is a bright yellow...
in the production of iron and steel, the production of titanium
Titanium
Titanium is a chemical element with the symbol Ti and atomic number 22. It has a low density and is a strong, lustrous, corrosion-resistant transition metal with a silver color....
in the Kroll process
Kroll process
Kroll Process is a pyrometallurgical industrial process used to produce metallic titanium. It was invented by William J. Kroll in Luxembourg. After moving to the United States, Kroll further developed the method for the production of zirconium...
.
Magnesium, in its purest form, can be compared with aluminium, and is strong and light, so it is used in several high volume part manufacturing applications, including automotive and truck components. Specialty, high-grade car wheels of magnesium alloy are called "mag wheels", although the term is often more broadly misapplied to include aluminum wheels. In 1957, a Corvette
Corvette
A corvette is a small, maneuverable, lightly armed warship, originally smaller than a frigate and larger than a coastal patrol craft or fast attack craft , although many recent designs resemble frigates in size and role...
SS, designed for racing, was constructed with magnesium body panels. An earlier Mercedes-Benz
Mercedes-Benz
Mercedes-Benz is a German manufacturer of automobiles, buses, coaches, and trucks. Mercedes-Benz is a division of its parent company, Daimler AG...
race car model, the Mercedes-Benz 300 SLR
Mercedes-Benz 300 SLR
The Mercedes-Benz 300 SLR was a sportscar racing car for the 1955 World Sportscar Championship season, which it won.-Technical highlights:...
, had a body made from Elektron
Elektron (alloy)
Elektron was a magnesium alloy developed in Germany during the First World War between 1914-18 as a substitute for aluminium alloy. Elektron is unusually light and has a specific gravity of about 1.8 compared with the 2.8 of aluminium alloy. Elektron was used to make incendiary bombs: the B-1E...
, a magnesium alloy; these cars ran (with successes) at Le Mans
24 Hours of Le Mans
The 24 Hours of Le Mans is the world's oldest sports car race in endurance racing, held annually since near the town of Le Mans, France. Commonly known as the Grand Prix of Endurance and Efficiency, race teams have to balance speed against the cars' ability to run for 24 hours without sustaining...
, the Mille Miglia
Mille Miglia
The Mille Miglia was an open-road endurance race which took place in Italy twenty-four times from 1927 to 1957 ....
, and other world-class race events in 1955 (though one was involved in the single worst accident in auto racing history
1955 Le Mans disaster
The 1955 Le Mans disaster occurred during the 1955 24 Hours of Le Mans motor race, when a crash caused large parts of racing car debris to fly into the crowd. The driver was killed, as were 83 spectators. A further 120 people were injured...
, in terms of human casualties, at the Le Mans race.) Porsche's all-out quest to decrease the weight of their race cars led to the use of magnesium frames in the famous 917/053 that won Le Mans in 1971, and still holds the absolute distance record. The 917/30 Can-Am car also featured a magnesium frame, helping it to make the most of its prodigious 1100–1500 hp. Volkswagen Group
Volkswagen Group
Volkswagen Group is a German multinational automobile manufacturing group. , Volkswagen was ranked as the world’s third largest motor vehicle manufacturer and Europe's largest....
has used magnesium in its engine components for many years. For a long time, Porsche
Porsche
Porsche Automobil Holding SE, usually shortened to Porsche SE a Societas Europaea or European Public Company, is a German based holding company with investments in the automotive industry....
used magnesium alloy for its engine blocks due to the weight advantage. There is renewed interest in magnesium engine blocks, as featured in the 2006 BMW
BMW
Bayerische Motoren Werke AG is a German automobile, motorcycle and engine manufacturing company founded in 1916. It also owns and produces the Mini marque, and is the parent company of Rolls-Royce Motor Cars. BMW produces motorcycles under BMW Motorrad and Husqvarna brands...
325i and 330i models. The BMW engine uses an aluminium alloy insert for the cylinder walls and cooling jackets surrounded by a high-temperature magnesium alloy AJ62A. The application of magnesium AE44 alloy in the 2006 Corvette Z06 engine cradle has advanced the technology of designing robust automotive parts in magnesium. Both these alloys are recent developments in high-temperature low creep
Creep (deformation)
In materials science, creep is the tendency of a solid material to slowly move or deform permanently under the influence of stresses. It occurs as a result of long term exposure to high levels of stress that are below the yield strength of the material....
magnesium alloys. Mitsubishi Motors also uses magnesium (branded magnesium alloy) for its paddle shifters. The general strategy for such alloys is to form intermetallic precipitates at the grain boundaries
Crystallite
Crystallites are small, often microscopic crystals that, held together through highly defective boundaries, constitute a polycrystalline solid. Metallurgists often refer to crystallites as grains.- Details :...
, for example by adding mischmetal
Mischmetal
Mischmetal is an alloy of rare earth elements in various naturally occurring proportions. It is also called cerium mischmetal, rare earth mischmetal or misch metal. A typical composition includes approximately 50% cerium and 25% lanthanum, with small amounts of neodymium and praseodymium...
or calcium
Calcium
Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth-most-abundant element by mass in the Earth's crust...
. New alloy development and lower costs, which are becoming competitive to aluminium, will further the number of automotive applications.
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
Elektron (alloy)
Elektron was a magnesium alloy developed in Germany during the First World War between 1914-18 as a substitute for aluminium alloy. Elektron is unusually light and has a specific gravity of about 1.8 compared with the 2.8 of aluminium alloy. Elektron was used to make incendiary bombs: the B-1E...
' for magnesium alloy. The term is still used today. Because of perceived hazards with magnesium parts in the event of fire, the application of magnesium in the commercial aerospace industry was generally restricted to engine related components. Currently the use of magnesium alloys in aerospace is increasing, mostly driven by the increasing importance of fuel economy and the need to reduce weight. The development and testing of new magnesium alloys continues, notably Elektron 21, which has successfully undergone extensive aerospace testing for suitability in engine, internal and airframe components. The European Community runs three R&D magnesium projects in the Aerospace priority of Six Framework Program.
Niche Uses of the Metal
Magnesium, being available and relatively nontoxic, has variety of uses:- Magnesium is flammable, burning at a temperature of approximately 3100 °C (3,373.2 K; 5,612 °F), and the autoignition temperatureAutoignition temperatureThe autoignition temperature or kindling point of a substance is the lowest temperature at which it will spontaneously ignite in a normal atmosphere without an external source of ignition, such as a flame or spark. This temperature is required to supply the activation energy needed for combustion...
of magnesium ribbon is approximately 630 °C (903.2 K; 1,166 °F) in air. It produces intense, bright, white light when it burns. Magnesium's high burning temperature makes it a useful tool for starting emergency fires during outdoor recreation. Other uses include flash photographyPhotographyPhotography is the art, science and practice of creating durable images by recording light or other electromagnetic radiation, either electronically by means of an image sensor or chemically by means of a light-sensitive material such as photographic film...
, flares, pyrotechnicsPyrotechnicsPyrotechnics is the science of using materials capable of undergoing self-contained and self-sustained exothermic chemical reactions for the production of heat, light, gas, smoke and/or sound...
and fireworks sparklers.
- In the form of turnings or ribbons, to prepare Grignard reagents, which are useful in organic synthesisOrganic synthesisOrganic synthesis is a special branch of chemical synthesis and is concerned with the construction of organic compounds via organic reactions. Organic molecules can often contain a higher level of complexity compared to purely inorganic compounds, so the synthesis of organic compounds has...
. - As an additive agent in conventional propellants and the production of nodular graphite in cast ironDuctile ironDuctile iron, also known as ductile cast iron, nodular cast iron, spheroidal graphite iron, spherulitic graphite cast iron and SG iron, is a type of cast iron invented in 1943 by Keith Millis...
. - As a reducing agent for the production of uraniumUraniumUranium is a silvery-white metallic chemical element in the actinide series of the periodic table, with atomic number 92. It is assigned the chemical symbol U. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons...
and other metals from their saltSaltIn chemistry, salts are ionic compounds that result from the neutralization reaction of an acid and a base. They are composed of cations and anions so that the product is electrically neutral...
s. - As a sacrificial (galvanic) anode to protect underground tanks, pipelines, buried structures, and water heaters.
- Alloyed with zinc to produce the zinc sheet used in photoengravingPhotoengravingPhotoengraving also known as photo-chemical milling is a process of engraving using photographic processing techniques. The full form of photoengraving is photo mechanical process in the graphic arts, used principally for reproducing illustrations. The subject is photographed, and the image is...
plates in the printing industry, dry-cell batteryDry Cell-Dry Cell's formation:Part of the band formed in 1998 when guitarist Danny Hartwell and drummer Brandon Brown met at the Ratt Show on the Sunset Strip. They later met up with then-vocalist Judd Gruenbaum. The original name of the band was "Beyond Control"....
walls, and roofingFlashing (weatherproofing)Flashing refers to thin continuous pieces of sheet metal or other impervious material installed to prevent the passage of water into a structure from an angle or joint...
. - As a metal, this element's principal use is as an alloying additive to aluminium with these aluminium-magnesium alloys being used mainly for beverage canBeverage canA beverage can is a tin can designed to hold a specific portion of a beverage. Beverage cans are made of tin-plated steel or aluminium.- History :...
s.
As Magnesium Compounds
The magnesium ion is necessary for all life (see magnesium in biologyMagnesium in biology
Magnesium is an essential element in biological systems. Magnesium occurs typically as the Mg2+ ion. It is an essential mineral nutrient for life and is present in every cell type in every organism. For example, ATP , the main source of energy in cells, must be bound to a magnesium ion in order to...
), so magnesium salts are frequently included in various food
Food
Food is any substance consumed to provide nutritional support for the body. It is usually of plant or animal origin, and contains essential nutrients, such as carbohydrates, fats, proteins, vitamins, or minerals...
s, fertilizer
Fertilizer
Fertilizer is any organic or inorganic material of natural or synthetic origin that is added to a soil to supply one or more plant nutrients essential to the growth of plants. A recent assessment found that about 40 to 60% of crop yields are attributable to commercial fertilizer use...
s (magnesium is a component of chlorophyll
Chlorophyll
Chlorophyll is a green pigment found in almost all plants, algae, and cyanobacteria. Its name is derived from the Greek words χλωρος, chloros and φύλλον, phyllon . Chlorophyll is an extremely important biomolecule, critical in photosynthesis, which allows plants to obtain energy from light...
), and culture media.
Magnesium compounds, primarily magnesium oxide
Magnesium oxide
Magnesium oxide , or magnesia, is a white hygroscopic solid mineral that occurs naturally as periclase and is a source of magnesium . It has an empirical formula of and consists of a lattice of Mg2+ ions and O2– ions held together by ionic bonds...
(MgO), are used as refractory
Refractory
A refractory material is one that retains its strength at high temperatures. ASTM C71 defines refractories as "non-metallic materials having those chemical and physical properties that make them applicable for structures, or as components of systems, that are exposed to environments above...
a material in furnace
Furnace
A furnace is a device used for heating. The name derives from Latin fornax, oven.In American English and Canadian English, the term furnace on its own is generally used to describe household heating systems based on a central furnace , and sometimes as a synonym for kiln, a device used in the...
linings for producing iron
Iron
Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...
, steel
Steel
Steel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten...
, nonferrous metals, glass
Glass
Glass is an amorphous solid material. Glasses are typically brittle and optically transparent.The most familiar type of glass, used for centuries in windows and drinking vessels, is soda-lime glass, composed of about 75% silica plus Na2O, CaO, and several minor additives...
and cement
Cement
In the most general sense of the word, a cement is a binder, a substance that sets and hardens independently, and can bind other materials together. The word "cement" traces to the Romans, who used the term opus caementicium to describe masonry resembling modern concrete that was made from crushed...
. Magnesium oxide and other magnesium compounds are also used in the agricultural, chemical, and construction industries.
Magnesium reacted with an alkyl halide gives a Gringard reagent
Grignard reaction
The Grignard reaction is an organometallic chemical reaction in which alkyl- or aryl-magnesium halides add to a carbonyl group in an aldehyde or ketone. This reaction is an important tool for the formation of carbon–carbon bonds...
, which is a very useful tool for preparing alcohols.
Niche and Illustrative Uses of Magnesium Compounds
- Magnesium sulfateMagnesium sulfateMagnesium sulfate is a chemical compound containing magnesium, sulfur and oxygen, with the formula MgSO4. It is often encountered as the heptahydrate epsomite , commonly called Epsom salt, from the town of Epsom in Surrey, England, where the salt was distilled from the springs that arise where the...
, as the heptahydrateHydrateHydrate is a term used in inorganic chemistry and organic chemistry to indicate that a substance contains water. The chemical state of the water varies widely between hydrates, some of which were so labeled before their chemical structure was understood....
called Epsom salts, is used as bath saltsBath saltsThe term bath salts refers to a range of water-soluble, usually inorganic solid products designed to be added to a bath. They are said to improve cleaning, improve the experience of bathing, and serve as a vehicle for cosmetic agents...
, as a laxativeLaxativeLaxatives are foods, compounds, or drugs taken to induce bowel movements or to loosen the stool, most often taken to treat constipation. Certain stimulant, lubricant, and saline laxatives are used to evacuate the colon for rectal and/or bowel examinations, and may be supplemented by enemas under...
, and as a highly soluble fertilizerFertilizerFertilizer is any organic or inorganic material of natural or synthetic origin that is added to a soil to supply one or more plant nutrients essential to the growth of plants. A recent assessment found that about 40 to 60% of crop yields are attributable to commercial fertilizer use...
. - Magnesium hydroxideMagnesium hydroxideMagnesium hydroxide is an inorganic compound with the chemical formula Mg2. As a suspension in water, it is often called milk of magnesia because of its milk-like appearance. The solid mineral form of magnesium hydroxide is known as brucite....
, suspended in water, is used in milk of magnesia antacidAntacidAn antacid is a substance which neutralizes stomach acidity.-Mechanism of action:Antacids perform a neutralization reaction, increasing the pH to reduce acidity in the stomach. When gastric hydrochloric acid reaches the nerves in the gastrointestinal mucosa, they signal pain to the central nervous...
s and laxativeLaxativeLaxatives are foods, compounds, or drugs taken to induce bowel movements or to loosen the stool, most often taken to treat constipation. Certain stimulant, lubricant, and saline laxatives are used to evacuate the colon for rectal and/or bowel examinations, and may be supplemented by enemas under...
s. - Magnesium chlorideMagnesium chlorideMagnesium chloride is the name for the chemical compounds with the formulas MgCl2 and its various hydrates MgCl2x. These salts are typical ionic halides, being highly soluble in water. The hydrated magnesium chloride can be extracted from brine or sea water...
, oxideMagnesium oxideMagnesium oxide , or magnesia, is a white hygroscopic solid mineral that occurs naturally as periclase and is a source of magnesium . It has an empirical formula of and consists of a lattice of Mg2+ ions and O2– ions held together by ionic bonds...
, gluconateMagnesium gluconateMagnesium gluconate is a compound with formula MgC12H22O14. It is the magnesium salt of gluconic acid.It has E number "E580".-Use in medicine:There are data on the pharmacological properties of magnesium gluconate...
, malateMagnesium malateMagnesium malate, the magnesium salt of malic acid, is a mineral supplement....
, orotateMagnesium orotateMagnesium orotate, the magnesium salt of orotic acid, is a mineral supplement....
and citrateMagnesium citrateMagnesium citrate, a magnesium salt of citric acid, is a chemical agent used medicinally as a saline laxative and to completely empty the bowel prior to a major surgery or colonoscopy. It is available without a prescription, both as a generic brand or under the brand name Citromag or Citroma. It is...
are all used as oral magnesium supplements. Oral magnesium supplements have been claimed to be therapeutic for some individuals who suffer from Restless Leg Syndrome (RLS). - Magnesium borateBorateBorates are chemical compounds which contain oxoanions of boron in oxidation state +3. The simplest borate ion, BO33−, has a trigonal planar structure. Other borates are made up of trigonal BO3 or tetrahedral BO4 structural units, sharing oxygen atoms...
, magnesium salicylateMagnesium salicylateMagnesium salicylate is a common analgesic and non-steroidal anti-inflammatory drug used to treat mild to moderate muscular pain. It is also used to treat headaches, general back pain, and certain joint pains like arthritis....
, and magnesium sulfateMagnesium sulfateMagnesium sulfate is a chemical compound containing magnesium, sulfur and oxygen, with the formula MgSO4. It is often encountered as the heptahydrate epsomite , commonly called Epsom salt, from the town of Epsom in Surrey, England, where the salt was distilled from the springs that arise where the...
are all used as antisepticAntisepticAntiseptics are antimicrobial substances that are applied to living tissue/skin to reduce the possibility of infection, sepsis, or putrefaction...
s. - Magnesium bromideMagnesium bromideMagnesium bromide is a chemical compound of magnesium and bromine that is white and deliquescent. It is often used as a mild sedative and as an anticonvulsant for treatment of nervous disorders. It is water soluble and somewhat soluble in alcohol...
is used as a mild sedativeSedativeA sedative or tranquilizer is a substance that induces sedation by reducing irritability or excitement....
(this action is due to the bromideBromideA bromide is a chemical compound containing bromide ion, that is bromine atom with effective charge of −1. The class name can include ionic compounds such as caesium bromide or covalent compounds such as sulfur dibromide.-Natural occurrence:...
, not the magnesium). - Dead-burned magnesite (magnesium carbonateMagnesium carbonateMagnesium carbonate, MgCO3, is a white solid that occurs in nature as a mineral. Several hydrated and basic forms of magnesium carbonate also exist as minerals...
) is used for refractory purposes such as brick and liners in furnaces and converters. - Magnesium carbonate powder is used by such athletes as gymnastsGymnasticsGymnastics is a sport involving performance of exercises requiring physical strength, flexibility, agility, coordination, and balance. Internationally, all of the gymnastic sports are governed by the Fédération Internationale de Gymnastique with each country having its own national governing body...
and weightlifters to improve their grip on a gymnastic apparatus, lifting bar, or other object. - Magnesium stearateMagnesium stearateMagnesium stearate, also called octadecanoic acid, magnesium salt, is a white substance which is solid at room temperature. It has the chemical formula . It is a salt containing two equivalents of stearate and one magnesium cation...
is a slightly flammableFireFire is the rapid oxidation of a material in the chemical process of combustion, releasing heat, light, and various reaction products. Slower oxidative processes like rusting or digestion are not included by this definition....
white powderPowder (substance)A powder is a dry,thick bulk solid composed of a large number of very fine particles that may flow freely when shaken or tilted. Powders are a special sub-class of granular materials, although the terms powder and granular are sometimes used to distinguish separate classes of material...
with lubricatingLubricantA lubricant is a substance introduced to reduce friction between moving surfaces. It may also have the function of transporting foreign particles and of distributing heat...
properties. In pharmaceuticalPharmacologyPharmacology is the branch of medicine and biology concerned with the study of drug action. More specifically, it is the study of the interactions that occur between a living organism and chemicals that affect normal or abnormal biochemical function...
technology, it is used in the manufacturing of numerous kinds of tabletTabletA tablet is a pharmaceutical dosage form. It comprises a mixture of active substances and excipients, usually in powder form, pressed or compacted from a powder into a solid dose...
s to prevent the tablets from sticking to the equipment during the tablet compression process (i.e., when the tablet's substance is pressed into tablet form). - Magnesium sulfiteMagnesium sulfiteMagnesium sulfite is the magnesium salt of sulfurous acid with the formula . Its most common hydrated form has 6 water molecules making it a hexahydrate, ·6. When heated above , it is dehydrated to magnesium sulfite trihydrate, or ·3. The anhydrous form is hygroscopic, meaning that it readily...
is used in the manufacture of paperPaperPaper is a thin material mainly used for writing upon, printing upon, drawing or for packaging. It is produced by pressing together moist fibers, typically cellulose pulp derived from wood, rags or grasses, and drying them into flexible sheets....
(sulfite processSulfite processThe sulfite process produces wood pulp which is almost pure cellulose fibers by using various salts of sulfurous acid to extract the lignin from wood chips in large pressure vessels called digesters. The salts used in the pulping process are either sulfites , or bisulfites , depending on the pH...
). - Magnesium phosphateMagnesium phosphateMagnesium phosphate is a general term for salts of magnesium and phosphate appearing in three forms:* Magnesium phosphate monobasic * Magnesium phosphate dibasic * Magnesium phosphate tribasic...
is used to fireproof wood used in construction. - Magnesium hexafluorosilicate is used in mothproofing of textileTextileA textile or cloth is a flexible woven material consisting of a network of natural or artificial fibres often referred to as thread or yarn. Yarn is produced by spinning raw fibres of wool, flax, cotton, or other material to produce long strands...
s.
Biological role
Because of the important interaction between phosphatePhosphate
A phosphate, an inorganic chemical, is a salt of phosphoric acid. In organic chemistry, a phosphate, or organophosphate, is an ester of phosphoric acid. Organic phosphates are important in biochemistry and biogeochemistry or ecology. Inorganic phosphates are mined to obtain phosphorus for use in...
and magnesium ions, magnesium ions are essential to the basic nucleic acid
Nucleic acid
Nucleic acids are biological molecules essential for life, and include DNA and RNA . Together with proteins, nucleic acids make up the most important macromolecules; each is found in abundance in all living things, where they function in encoding, transmitting and expressing genetic information...
chemistry of life, and thus are essential to all cells of all known living organisms. Over 300 enzyme
Enzyme
Enzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates...
s require the presence of magnesium ions for their catalytic action, including all enzymes utilizing or synthesizing ATP
Adenosine triphosphate
Adenosine-5'-triphosphate is a multifunctional nucleoside triphosphate used in cells as a coenzyme. It is often called the "molecular unit of currency" of intracellular energy transfer. ATP transports chemical energy within cells for metabolism...
, or those that use other nucleotides to synthesize DNA
DNA
Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms . The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in...
and RNA
RNA
Ribonucleic acid , or RNA, is one of the three major macromolecules that are essential for all known forms of life....
. ATP exists in cells normally as a chelate of ATP and a magnesium ion.
Plants have an additional use for magnesium in that chlorophyll
Chlorophyll
Chlorophyll is a green pigment found in almost all plants, algae, and cyanobacteria. Its name is derived from the Greek words χλωρος, chloros and φύλλον, phyllon . Chlorophyll is an extremely important biomolecule, critical in photosynthesis, which allows plants to obtain energy from light...
s are magnesium-centered porphyrin
Porphyrin
Porphyrins are a group of organic compounds, many naturally occurring. One of the best-known porphyrins is heme, the pigment in red blood cells; heme is a cofactor of the protein hemoglobin. Porphyrins are heterocyclic macrocycles composed of four modified pyrrole subunits interconnected at...
s. Magnesium deficiency
Magnesium deficiency
Magnesium deficiency is a detrimental plant disorder that occurs most often in strongly acidic, light, sandy soils, where magnesium can be easily leached away. Magnesium is an essential macronutrient found from 0.2-0.4% dry matter and is necessary for normal plant growth...
in plants causes late-season yellowing between leaf veins, especially in older leaves, and can be corrected by applying Epsom salts (which is rapidly leached
Leaching (chemical science)
Leaching is the process of extracting minerals from a solid by dissolving them in a liquid, either in nature or through an industrial process. In the chemical processing industry, leaching has a variety of commercial applications, including separation of metal from ore using acid, and sugar from...
), or else crushed dolomitic
Dolomite
Dolomite is a carbonate mineral composed of calcium magnesium carbonate CaMg2. The term is also used to describe the sedimentary carbonate rock dolostone....
limestone
Limestone
Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....
to the soil.
Magnesium deficiency (medicine)
Magnesium deficiency refers to an intake of dietary magnesium below minimal levels, which can result in numerous symptoms and diseases. These can generally be remedied by an increase of magnesium in diet or oral supplements...
(including conditions that show few overt symptoms) is relatively rare although only 32% of the United States meet the RDA-DRI; low levels of magnesium in the body has been associated with the development of a number of human illnesses such as asthma
Asthma
Asthma is the common chronic inflammatory disease of the airways characterized by variable and recurring symptoms, reversible airflow obstruction, and bronchospasm. Symptoms include wheezing, coughing, chest tightness, and shortness of breath...
, diabetes, and osteoporosis
Osteoporosis
Osteoporosis is a disease of bones that leads to an increased risk of fracture. In osteoporosis the bone mineral density is reduced, bone microarchitecture is deteriorating, and the amount and variety of proteins in bone is altered...
.
Adult human bodies contain about 24 grams of magnesium, with 60% in the skeleton
Skeleton
The skeleton is the body part that forms the supporting structure of an organism. There are two different skeletal types: the exoskeleton, which is the stable outer shell of an organism, and the endoskeleton, which forms the support structure inside the body.In a figurative sense, skeleton can...
, 39% intracellular (20% in skeletal muscle), and 1% extracellular. Serum levels are typically 0.7–1.0 mmol/L or 1.8–2.4 mEq/L. Serum magnesium levels may appear normal even in cases of underlying intracellular deficiency, although no known mechanism maintains a homeostatic level in the blood other than renal excretion of high blood levels.
Intracellular magnesium is correlated with intracellular potassium
Potassium
Potassium is the chemical element with the symbol K and atomic number 19. Elemental potassium is a soft silvery-white alkali metal that oxidizes rapidly in air and is very reactive with water, generating sufficient heat to ignite the hydrogen emitted in the reaction.Potassium and sodium are...
. Magnesium is absorbed in the gastrointestinal tract, with more absorbed when status is lower. In humans, magnesium appears to facilitate calcium
Calcium
Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth-most-abundant element by mass in the Earth's crust...
absorption. Low and high protein intake inhibit magnesium absorption, and other factors such as phosphate
Phosphate
A phosphate, an inorganic chemical, is a salt of phosphoric acid. In organic chemistry, a phosphate, or organophosphate, is an ester of phosphoric acid. Organic phosphates are important in biochemistry and biogeochemistry or ecology. Inorganic phosphates are mined to obtain phosphorus for use in...
, phytate, and fat
Fat
Fats consist of a wide group of compounds that are generally soluble in organic solvents and generally insoluble in water. Chemically, fats are triglycerides, triesters of glycerol and any of several fatty acids. Fats may be either solid or liquid at room temperature, depending on their structure...
affect absorption. Absorbed dietary magnesium is largely excreted through the urine, although most magnesium "administered orally" is excreted through the feces. Magnesium status may be assessed roughly through serum and erythrocyte Mg concentrations and urinary and fecal excretion, but intravenous magnesium loading tests are likely the most accurate and practical in most people. In these tests, magnesium is injected intravenously; a retention of 20% or more indicates deficiency. Other nutrient deficiencies are identified through biomarkers, but none are established for magnesium.
Spices, nuts, cereals, coffee, cocoa, tea, and vegetables are rich sources of magnesium. Green leafy vegetables such as spinach
Spinach
Spinach is an edible flowering plant in the family of Amaranthaceae. It is native to central and southwestern Asia. It is an annual plant , which grows to a height of up to 30 cm. Spinach may survive over winter in temperate regions...
are also rich in magnesium as they contain chlorophyll. Observations of reduced dietary magnesium intake in modern Western countries compared to earlier generations may be related to food refining and modern fertilizers that contain no magnesium.
Numerous magnesium dietary supplement
Dietary supplement
A dietary supplement, also known as food supplement or nutritional supplement, is a preparation intended to supplement the diet and provide nutrients, such as vitamins, minerals, fiber, fatty acids, or amino acids, that may be missing or may not be consumed in sufficient quantities in a person's diet...
s are available. Magnesium oxide
Magnesium oxide
Magnesium oxide , or magnesia, is a white hygroscopic solid mineral that occurs naturally as periclase and is a source of magnesium . It has an empirical formula of and consists of a lattice of Mg2+ ions and O2– ions held together by ionic bonds...
, one of the most common because it has high magnesium content per weight, has been reported to be the least bioavailable
Bioavailability
In pharmacology, bioavailability is a subcategory of absorption and is used to describe the fraction of an administered dose of unchanged drug that reaches the systemic circulation, one of the principal pharmacokinetic properties of drugs. By definition, when a medication is administered...
. Magnesium citrate
Magnesium citrate
Magnesium citrate, a magnesium salt of citric acid, is a chemical agent used medicinally as a saline laxative and to completely empty the bowel prior to a major surgery or colonoscopy. It is available without a prescription, both as a generic brand or under the brand name Citromag or Citroma. It is...
has been reported as more bioavailable than oxide or amino-acid chelate (glycinate) forms.
Excess magnesium in the blood is freely filtered at the kidneys, and for this reason it is difficult to overdose on magnesium from dietary sources alone. With supplements, overdose is possible, however, particularly in people with poor renal function; occasionally, with use of high cathartic doses of magnesium salts, severe hypermagnesemia
Hypermagnesemia
Hypermagnesemia is an electrolyte disturbance in which there is an abnormally elevated level of magnesium in the blood. Usually this results in excess of magnesium in the body....
has been reported to occur even without renal dysfunction. Alcoholism can produce a magnesium deficiency, which is easily reversed by oral or parenteral administration, depending on the degree of deficiency.
Detection in biological fluids
Magnesium concentrations in plasma or serum may be measured to monitor for efficacy and safety in those receiving the drug therapeutically, to confirm the diagnosis in potential poisoning victims or to assist in the forensic investigation in a case of fatal overdosage. The newborn children of mothers who received parenteral magnesium sulfate during labor may exhibit toxicity at serum magnesium levels that were considered appropriate for the mothers.Magnesium in Treatment-resistant Depression
There has been some speculation that magnesium deficiency can lead to depression. Cerebral spinal fluid (CSF) magnesium has been found low in treatment-resistant suicidal depression and in patients that have attempted suicide. Brain magnesium has been found low in TRD using phosphorus nuclear magnetic resonance spectroscopy, an accurate means for measuring brain magnesium. Blood and CSF magnesium do not appear well-correlated with major depression. Magnesium chloride in relatively small doses was found to be as effective in the treatment of depressed elderly type 2 diabetics with hypomagnesemia as imipramine 50 mg daily.Safety precautions
Magnesium metal and its alloys are explosive hazards; they are highly flammable in their pure form when molten or in powder or ribbon form. Burning or molten magnesium metal reacts violently with water. When working with powdered magnesium, safety glasses with welding eye protection
Eye protection
Eye protection is protective gear for the eyes, which comes in many types depending upon the threat that is to be reduced. The threats can be particles, light, wind blast, heat, sea spray or some type of ball or puck used in sports...
are employed, because the bright white light produced by burning magnesium contains ultraviolet
Ultraviolet
Ultraviolet light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than X-rays, in the range 10 nm to 400 nm, and energies from 3 eV to 124 eV...
light that can permanently damage the retina
Retina
The vertebrate retina is a light-sensitive tissue lining the inner surface of the eye. The optics of the eye create an image of the visual world on the retina, which serves much the same function as the film in a camera. Light striking the retina initiates a cascade of chemical and electrical...
s of the eyes.
Magnesium is capable of reducing water to the highly flammable hydrogen
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
gas:
- Mg (s) + 2 (l) → (s) + (g)
As a result, water cannot be used to extinguish magnesium fires; the hydrogen gas produced will only intensify the fire. Dry sand is an effective smothering agent but is usable only on relatively level and flat surfaces.
Magnesium also reacts with carbon dioxide
Carbon dioxide
Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...
to form magnesium oxide and carbon
Carbon
Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...
:
- 2 Mg (s) + → 2 MgO (s) + C (s)
Hence, carbon dioxide fire extinguishers cannot be used for extinguishing magnesium fires either.
Burning magnesium is usually quenched by using a Class D dry chemical fire extinguisher, or by covering the fire with sand
Sand
Sand is a naturally occurring granular material composed of finely divided rock and mineral particles.The composition of sand is highly variable, depending on the local rock sources and conditions, but the most common constituent of sand in inland continental settings and non-tropical coastal...
or magnesium foundry flux to remove its air source.
See Also
External Links
- Chemistry in its element podcast (MP3) from the Royal Society of ChemistryRoyal Society of ChemistryThe Royal Society of Chemistry is a learned society in the United Kingdom with the goal of "advancing the chemical sciences." It was formed in 1980 from the merger of the Chemical Society, the Royal Institute of Chemistry, the Faraday Society and the Society for Analytical Chemistry with a new...
's Chemistry WorldChemistry WorldChemistry World is a monthly chemistry news magazine published by the Royal Society of Chemistry. The magazine addresses current events in world of chemistry including research, international business news and government policy as it affects the chemical science community, plus the best product...
: Magnesium