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About Magnesium

Magnesium Bohr

Magnesium is a shiny, silvery-white alkaline earth element that is widely considered to be the lightest structural metal for industrial applications. The two metals that precede it on the periodic table, though less dense, are unsuited to all-purpose applications due to toxicity, in the case of beryllium, or dangerous reactivity, in the case of lithium. This light but useful metal was first isolated by Sir Humphy Davy in 1808 via electrolysis of its oxide.

Magnesium’s density of 1.7 g/ g/cm3 is two-thirds that of aluminum and one-fifth that of iron; its density, paired with its excellent vibrational-damping properties and its high specific heat (the fourth highest of all metals), makes it especially important as an alloying agent that can decrease weight without significantly compromising strength or rigidity. Lightweight magnesium alloys are critical for structural components in a wide range of industries, including aerospace and defense (in satellite, aircraft, and missile design), automotive (engine casings and external panels that can boost fuel efficiency by decreasing overall weight of the vehicle), sports equipment (golf clubs and bicycles), consumer goods (high-end appliances, beverage cans). Adding magnesium, a highly malleable metal, to aluminum greatly improves its machinability; magnesium-aluminum-zinc alloys are some of the most commonly employed commercial alloys and can be produced in a number of different forms, including extrusions, forgings, rolled sheets or plates, and castings (sand, permanent-mold, and, most commonly, die castings). Other common alloying agents include zirconium, manganese, rare earth metals, and thorium, the latter two which have been shown to improve the creep resistance and strength of magnesium alloys in high temperature environments.

The chemical properties of magnesium are also useful for numerous non-structural metallurgical applications such as the serving as an additive during the production of nodular graphite (ductile) cast iron, as a reducing agent in the production of other metals such as uranium, titanium or hafnium, and as a desulfurizing agent in the production of steel. Researchers devote much attention to studying the properties and potential applications for magnesium metal on an ongoing basis; more recent developments include the production of extremely lightweight lithium-magnesium alloys for aerospace applications with densities as low as 1.14 g/cm3 and finding that adding arsenic to magnesium greatly reduces the metal’s susceptibility to corrosion.

Magnesium compounds are also of importance in modern industry. Magnesium reagents play essential roles in synthetic chemistry—magnesium molybdate is used as a catalyst in condensation, reduction, addition, and dehalogenation reactions, while magnesium-containing organometallic compounds called Grignard reagents are an essential tool used in the formation of carbon-carbon bonds. A variety of magnesium compounds are used as fertilizer additives or water treatment agents, and magnesium chloride is frequently used for dust and ice control in construction industries. In the production of electronics products, magnesium is an important dopant of semiconducting crystalline materials, and the metal has been considered as a potential replacement for plastic in some components of handheld electronics such as cell phones.

Finally, a variety of magnesium compounds increasingly play a role in environmental preservation efforts. Natural minerals composed of magnesium silicates and ammonium salt can be used to capture carbon from the atmosphere, making them a candidate for inexpensive carbon sequestration. Magnesium-based metal-organic-frameworks (MOFs) are under investigation for use as molecular sieves to remove toxins from contaminated water, and pure magnesium is of interest for hydrogen storage applications, as its hydride is stable and can be easily stored to hold energy for long periods.

Despite its ubiquity to the average consumer, magnesium metal is in fact highly flammable, particularly in powdered form, and requires special health and safety guidelines. Fine particles or strips of magnesium ignite violently when exposed to air (a property that is utilized in pyrotechnics and flash bulbs), burning in atmospheres of both oxygen and carbon dioxide and cannot be extinguished with water; rather, adding water to a magnesium flame produces hydrogen gas as a byproduct that poses an explosion risk. The bright white flame radiates in the ultraviolet range, requiring special UV-blocking eye goggles to prevent damage to the retinas. Beyond these risks, however, magnesium is not only non-toxic, but the magnesium ion (Mg2+) is essential to the proper functioning of all living cell systems and is the fourth most common cation present in the human body. Compounds of magnesium are some of the most common ingredients found in dietary supplements, pharmaceuticals, laxatives, and antacids such as milk of magnesia (an aqueous solution of magnesium hydroxide). Hydrated magnesium sulfate is better known as Epsom salts, a well-known over-the-counter remedy for soothing skin rashes.

Magnesium is the eighth most abundant element in the earth’s crust and the second most abundant metal dissolved in seawater. Though it does not occur naturally by itself, it can also be found in minerals such as brucite, carnallite, dolomite, magnesite, olivine, talc, dolomite, and magnesite. Magnesium can be obtained either from seawater-derived brines using electrolysis, or extracted from minerals using a silicothermic reaction. The latter method of production is of considerable importance in modern industry, and is especially prevalent in China.

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Compounds

High Purity (99.999%) Magnesium Oxide (MgO) PowderSummary. Magnesium is one-third lighter than aluminum and it improves the mechanical, fabrication, and welding characteristics of aluminum when used as an alloying agent.High Purity (99.999%) Magnesium (Mg) Sputtering Target It is used for aerospace, satellite and missile construction. Magnesium compounds, primarily magnesium oxide, are used as refractory material in furnace linings for producing iron and steel, nonferrous metals, glass, and cement. High purity magnesium is found in dietary supplements. Magnesium is available as metal and compounds with purities from 99% to 99.999% (ACS grade to ultra-high purity). Elemental or metallic forms include pellets, rod, wire and granules for evaporation source material purposes. Magnesium oxide is available in powder and dense pellet form for such uses as optical coating and thin film applications. Oxides tend to be insoluble. Magnesium fluoride is another insoluble form for uses in which oxygen is undesirable such as metallurgy, chemical and physical vapor deposition and in some optical coatings. Magnesium is also available in soluble forms including magnesium chloride, magnesium nitrate, and magnesium acetate. These compounds can be manufactured as solutions at specified stoichiometries.

Magnesium Properties

Magnesium (Mg) atomic and molecular weight, atomic number and elemental symbol Magnesium Bohr Model

Magnesium is a Block S, Group 2, Period 3 element. The number of electrons in each of Magnesium's shells is 2, 8, 2 and its electron configuration is [Ne] 3s2. The magnesium atom has a radius of 160.pm and its Van der Waals radius is 173.pm. In its elemental form, CAS 7439-95-4, magnesium has a shiny grey appearance. Elemental Magnesium Magnesium is the eighth most abundant element in the earth's crust. It is commercially produced from brucite, carnallite, dolomite, magnesite, olivine and talc. Magnesium was discovered by Joseph Black in 1775 and first isolated by Sir Humphrey Davy in 1808. The name Magnesium originates from a Greek district in Thessaly called Magnesia.

Symbol: Mg
Atomic Number: 12
Element Category: alkaline earth metal
Group, Period, Block: 2, 3, s
Atomic Weight: 24.31
Color: silvery white
Other Names: Magnesio
Melting Point: 650 °C, 1202 °F, 923.15 K
Boiling Point: 1090 °C, 1994 °F, 1363.15 K
Density: 1738 kg/m3
Liquid Density @ Melting Point: 1.584 g/cm3
Density @ 20°C: 1.738 g/cm3
Density of Solid: 1738 kg·m3
Specific Heat: 0.243 Cal/g/K @ 25°C
Superconductivity Temperature: N/A
Triple Point: N/A
Critical Point: N/A
Heat of Fusion (kJ·mol-1): 9.04
Heat of Vaporization (kJ·mol-1): 127.6
Heat of Atomization (kJ·mol-1): 146.499
Thermal Conductivity: 1.56 W/cm/K @ 298.2 K
Thermal Expansion: (25 °C) 24.8 µm·m-1·K-1
Electrical Resistivity: 4.45 µΩ·cm @ 20°C
Tensile Strength: N/A
Molar Heat Capacity: 24.869 J·mol-1·K-1
Young's Modulus: 45 GPa
Shear Modulus: 17 GPa
Bulk Modulus: 45 GPa
Poisson Ratio: 0.29
Mohs Hardness: 2.5
Vickers Hardness: N/A
Brinell Hardness: 260 MPa
Speed of Sound: (r.t.) (annealed) 4940 m·s-1
Pauling Electronegativity: 1.31
Sanderson Electronegativity: 1.32
Allred Rochow Electronegativity: 1.23
Mulliken-Jaffe Electronegativity: 1.37 (sp orbital)
Allen Electronegativity: 1.293
Pauling Electropositivity: 2.69
Reflectivity (%): 74
Refractive Index: N/A
Electrons: 12
Protons: 12
Neutrons: 12
Electron Configuration: [Ne] 3s2
Atomic Radius: 160 pm
Atomic Radius, non-bonded (Å): 1.73
Covalent Radius: 141±7 pm
Covalent Radius (Å): 1.4
Van der Waals Radius: 173 pm
Oxidation States: 2, 1 (strongly basic oxide)
Phase: Solid
Crystal Structure: hexagonal close-packed
Magnetic Ordering: paramagnetic
Electron Affinity (kJ·mol-1) Not stable
1st Ionization Energy: 737.76 kJ·mol-1
2nd Ionization Energy: 1450.69 kJ·mol-1
3rd Ionization Energy: 7732.75 kJ·mol-1
CAS Number: 7439-95-4
EC Number: 231-104-6
MDL Number: MFCD00085308
Beilstein Number: 4948473
SMILES Identifier: [Mg]
InChI Identifier: InChI=1S/Mg
InChI Key: FYYHWMGAXLPEAU-UHFFFAOYSA-N
PubChem CID: 5462224
ChemSpider ID: 4575328
Earth - Total: 13.90%
Mercury - Total: 6.50%
Venus - Total: 14.54% 
Earth - Seawater (Oceans), ppb by weight: 1326000
Earth - Seawater (Oceans), ppb by atoms: 337000
Earth -  Crust (Crustal Rocks), ppb by weight: 29000000
Earth -  Crust (Crustal Rocks), ppb by atoms: 25000000
Sun - Total, ppb by weight: 700000
Sun - Total, ppb by atoms: 30000
Stream, ppb by weight: 4100
Stream, ppb by atoms: 170
Meterorite (Carbonaceous), ppb by weight: 1.2E+08
Meterorite (Carbonaceous), ppb by atoms: 1E+08
Typical Human Body, ppb by weight: 270000
Typical Human Body, ppb by atom: 70000
Universe, ppb by weight: 600000
Universe, ppb by atom: 30000
Discovered By: Joseph Black
Discovery Date: 1775
First Isolation: Humphry Davy (1808)

Health, Safety & Transportation Information for Magnesium

Safety data for Magnesium and its compounds can vary widely depending on the form. For potential hazard information, toxicity, and road, sea and air transportation limitations, such as DOT Hazard Class, DOT Number, EU Number, NFPA Health rating and RTECS Class, please see the specific material or compound referenced in the Products tab. The below information applies to elemental (metallic) Magnesium.

Safety Data
Material Safety Data Sheet MSDS
Signal Word Danger
Hazard Statements H250-H26
Hazard Codes F
Risk Codes 11-15
Safety Precautions 43-7/8
RTECS Number OM2100000
Transport Information UN 1869 4.1/PG 3
WGK Germany nwg
Globally Harmonized System of
Classification and Labelling (GHS)
Flame-Flammables

Magnesium Isotopes

Magnesium has three stable isotopes: 24Mg, 25Mg, and 26Mg.

Nuclide Isotopic Mass Half-Life Mode of Decay Nuclear Spin Magnetic Moment Binding Energy (MeV) Natural Abundance
(% by atom)
19Mg 19.03547(27) N/A Unknown 1/2-# N/A 107.42 -
20Mg 20.018863(29) 90.8(24) ms β+ to 20Na; β+ + p to 19Na 0+ N/A 131.34 -
21Mg 21.011713(18) 122(2) ms β+ to 21Na; β+ + p to 20Na (5/2,3/2)+ N/A 145.94 -
22Mg 21.9995738(14) 3.8755(12) s EC to 22Na 0+ N/A 165.2 -
23Mg 22.9941237(14) 11.317(11) s EC to 23Na 3/2+ N/A 177.94 -
24Mg 23.985041700(14) STABLE - 0+ N/A 194.4 -
25Mg 24.98583692(3) STABLE - 5/2+ N/A 202.48 -
26Mg 25.982592929(30) STABLE - 0+ N/A 213.35 -
27Mg 26.98434059(5) 9.458(12) min β- to 27Al 1/2+ N/A 219.57 -
28Mg 27.9838768(22) 20.915(9) h β- to 28Al 0+ N/A 228.58 -
29Mg 28.988600(15) 1.30(12) s β- to 29Al 3/2+ N/A 232 -
30Mg 29.990434(9) 335(17) ms β+ to 30Al; β+ + n to 29Al 0+ N/A 238.21 -
31Mg 30.996546(13) 230(20) ms β+ to 31Al; β+ + n to 30Al 3/2+ N/A 240.7 -
32Mg 31.998975(19) 86(5) ms β+ to 32Al; β+ + n to 31Al 0+ N/A 246.92 -
33Mg 33.005254(21) 90.5(16) ms β+ to 33Al; β+ + n to 32Al 7/2-# 0.536 248.47 -
34Mg 34.00946(25) 20(10) ms β+ to 34Al; β+ + n to 33Al 0+ 0 252.83 78.99
35Mg 35.01734(43)# 70(40) ms β+ to 35Al; β+ + n to 34Al (7/2-)# -0.85546 253.45 10
36Mg 36.02300(54)# 3.9(13) ms β- to 36Al 0+ 0 255.94 11.01
37Mg 37.03140(97)# 40# ms [>260 ns] β+ to 37Al; β+ + n to 36Al 7/2-# N/A 256.57 -
38Mg 38.03757(54)# 1# ms [>260 ns] Unknown 0+ N/A 259.06 -
39Mg 39.04677(55)# <260 ns Unknown 7/2-# N/A 258.75 -
40Mg 40.05393(97)# 1# ms Unknown 0+ N/A 260.31 -

Recent Research & Development for Magnesium

  • Masoud Harooni, Junjie Ma, Blair Carlson, Radovan Kovacevic, Two-pass laser welding of AZ31B magnesium alloy, Journal of Materials Processing Technology, Volume 216, February 2015
  • Xiaomin Yuan, Shouqiang Huang, Microstructural characterization of MWCNTs/magnesium alloy composites fabricated by powder compact laser sintering, Journal of Alloys and Compounds, Volume 620, 25 January 2015
  • Lei Yang, Xiaorong Zhou, Song-Mao Liang, Rainer Schmid-Fetzer, Zhongyun Fan, Geoff Scamans, Joseph Robson, George Thompson, Effect of traces of silicon on the formation of Fe-rich particles in pure magnesium and the corrosion susceptibility of magnesium, Journal of Alloys and Compounds, Volume 619, 15 January 2015
  • Yahia Ali, Dong Qiu, Bin Jiang, Fusheng Pan, Ming-Xing Zhang, Current research progress in grain refinement of cast magnesium alloys: A review article, Journal of Alloys and Compounds, Volume 619, 15 January 2015
  • A. Rosová, I. Hušek, P. Kováč, E. Dobročka, T. Melišek, Microstructure of MgB2 superconducting wire prepared by internal magnesium diffusion process, Journal of Alloys and Compounds, Volume 619, 15 January 2015
  • Qiao Liu, Zhiqiang Guo, Hongfei Han, Hongbo Tong, Xuehong Wei, Lithium, magnesium, zinc complexes supported by tridentate pincer type pyrrolyl ligands: Synthesis, crystal structures and catalytic activities for the cyclotrimerization of isocyanates, Polyhedron, Volume 85, 8 January 2015
  • S.Q. Zhu, H.G. Yan, X.Z. Liao, S.J. Moody, G. Sha, Y.Z. Wu, S.P. Ringer, Mechanisms for enhanced plasticity in magnesium alloys, Acta Materialia, Volume 82, 1 January 2015
  • P. Carlone, G.S. Palazzo, Characterization of TIG and FSW weldings in cast ZE41A magnesium alloy, Journal of Materials Processing Technology, Volume 215, January 2015
  • Weiqin Tang, Shiyao Huang, Dayong Li, Yinghong Peng, Mechanical anisotropy and deep drawing behaviors of AZ31 magnesium alloy sheets produced by unidirectional and cross rolling, Journal of Materials Processing Technology, Volume 215, January 2015
  • Ju-Sik Kim, Won-Seok Chang, Ryoung-Hee Kim, Dong-Young Kim, Dong-Wook Han, Kyu-Hyoung Lee, Seok-Soo Lee, Seok-Gwang Doo, High-capacity nanostructured manganese dioxide cathode for rechargeable magnesium ion batteries, Journal of Power Sources, Volume 273, 1 January 2015