This article is about the chemical element. For the use of magnesium as a medication, see Magnesium (medical use).
Not to be confused with manganese (Mn).
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Chemical element, symbol Mg and atomic number 12
Magnesium, 12Mg
Magnesium
Pronunciation
/mæɡˈniːziəm/(mag-NEE-zee-əm)
Appearance
shiny grey solid
Standard atomic weight Ar°(Mg)
[24.304, 24.307][1]
24.305±0.002 (abridged)[2]
Magnesium in the periodic table
Hydrogen
Helium
Lithium
Beryllium
Boron
Carbon
Nitrogen
Oxygen
Fluorine
Neon
Sodium
Magnesium
Aluminium
Silicon
Phosphorus
Sulfur
Chlorine
Argon
Potassium
Calcium
Scandium
Titanium
Vanadium
Chromium
Manganese
Iron
Cobalt
Nickel
Copper
Zinc
Gallium
Germanium
Arsenic
Selenium
Bromine
Krypton
Rubidium
Strontium
Yttrium
Zirconium
Niobium
Molybdenum
Technetium
Ruthenium
Rhodium
Palladium
Silver
Cadmium
Indium
Tin
Antimony
Tellurium
Iodine
Xenon
Caesium
Barium
Lanthanum
Cerium
Praseodymium
Neodymium
Promethium
Samarium
Europium
Gadolinium
Terbium
Dysprosium
Holmium
Erbium
Thulium
Ytterbium
Lutetium
Hafnium
Tantalum
Tungsten
Rhenium
Osmium
Iridium
Platinum
Gold
Mercury (element)
Thallium
Lead
Bismuth
Polonium
Astatine
Radon
Francium
Radium
Actinium
Thorium
Protactinium
Uranium
Neptunium
Plutonium
Americium
Curium
Berkelium
Californium
Einsteinium
Fermium
Mendelevium
Nobelium
Lawrencium
Rutherfordium
Dubnium
Seaborgium
Bohrium
Hassium
Meitnerium
Darmstadtium
Roentgenium
Copernicium
Nihonium
Flerovium
Moscovium
Livermorium
Tennessine
Oganesson
Be ↑ Mg ↓ Ca
sodium ← magnesium → aluminium
Atomic number (Z)
12
Group
group 2 (alkaline earth metals)
Period
period 3
Block
s-block
Electron configuration
[Ne] 3s2
Electrons per shell
2, 8, 2
Physical properties
Phase at STP
solid
Melting point
923 K (650 °C, 1202 °F)
Boiling point
1363 K (1091 °C, 1994 °F)
Density (at 20° C)
1.737 g/cm3[3]
when liquid (at m.p.)
1.584 g/cm3
Heat of fusion
8.48 kJ/mol
Heat of vaporization
128 kJ/mol
Molar heat capacity
24.869[4] J/(mol·K)
Vapor pressure
P(Pa)
1
10
100
1 k
10 k
100 k
at T(K)
701
773
861
971
1132
1361
Atomic properties
Oxidation states
0,[5] +1,[6]+2 (a strongly basic oxide)
Electronegativity
Pauling scale: 1.31
Ionization energies
1st: 737.7 kJ/mol
2nd: 1450.7 kJ/mol
3rd: 7732.7 kJ/mol
(more)
Atomic radius
empirical: 160 pm
Covalent radius
141±7 pm
Van der Waals radius
173 pm
Spectral lines of magnesium
Other properties
Natural occurrence
primordial
Crystal structure
hexagonal close-packed (hcp) (hP2)
Lattice constants
a = 320.91 pm c = 521.03 pm (at 20 °C)[3]
Thermal expansion
25.91×10−6/K (at 20 °C)[3][a]
Thermal conductivity
156[7] W/(m⋅K)
Electrical resistivity
43.9[8] nΩ⋅m (at 20 °C)
Magnetic ordering
paramagnetic
Molar magnetic susceptibility
+13.1×10−6 cm3/mol (298 K)[9]
Young's modulus
45 GPa
Shear modulus
17 GPa
Bulk modulus
35.4[10] GPa
Speed of sound thin rod
4940 m/s (at r.t.) (annealed)
Poisson ratio
0.290
Mohs hardness
1–2.5
Brinell hardness
44–260 MPa
CAS Number
7439-95-4
History
Naming
after Magnesia, Greece[11]
Discovery
Joseph Black (1755[11])
First isolation
Humphry Davy (1808[11])
Isotopes of magnesium
v
e
Main isotopes[12]
Decay
abundance
half-life (t1/2)
mode
product
24Mg
79%
stable
25Mg
10%
stable
26Mg
11%
stable
Category: Magnesium
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Magnesium is a chemical element; it has symbol Mg and atomic number 12. It is a shiny gray metal having a low density, low melting point and high chemical reactivity. Like the other alkaline earth metals (group 2 of the periodic table) it occurs naturally only in combination with other elements and it almost always has an oxidation state of +2. It reacts readily with air to form a thin passivation coating of magnesium oxide that inhibits further corrosion of the metal. The free metal burns with a brilliant-white light. The metal is obtained mainly by electrolysis of magnesium salts obtained from brine. It is less dense than aluminium and is used primarily as a component in strong and lightweight alloys that contain aluminium.
In the cosmos, magnesium is produced in large, aging stars by the sequential addition of three helium nuclei to a carbon nucleus. When such stars explode as supernovas, much of the magnesium is expelled into the interstellar medium where it may recycle into new star systems. Magnesium is the eighth most abundant element in the Earth's crust[13] and the fourth most common element in the Earth (after iron, oxygen and silicon), making up 13% of the planet's mass and a large fraction of the planet's mantle. It is the third most abundant element dissolved in seawater, after sodium and chlorine.[14]
This element is the eleventh most abundant element by mass in the human body and is essential to all cells and some 300 enzymes.[15] Magnesium ions interact with polyphosphate compounds such as ATP, DNA, and RNA. Hundreds of enzymes require magnesium ions to function. Magnesium compounds are used medicinally as common laxatives and antacids (such as milk of magnesia), and to stabilize abnormal nerve excitation or blood vessel spasm in such conditions as eclampsia.[15]
^Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; Böhlke, John K.; Chesson, Lesley A.; Coplen, Tyler B.; Ding, Tiping; Dunn, Philip J. H.; Gröning, Manfred; Holden, Norman E.; Meijer, Harro A. J. (4 May 2022). "Standard atomic weights of the elements 2021 (IUPAC Technical Report)". Pure and Applied Chemistry. doi:10.1515/pac-2019-0603. ISSN 1365-3075.
^ abcdArblaster, John W. (2018). Selected Values of the Crystallographic Properties of Elements. Materials Park, Ohio: ASM International. ISBN 978-1-62708-155-9.
^Rumble, p. 4.61
^Mg(0) has been synthesized in a compound containing a Na2Mg22+ cluster coordinated to a bulky organic ligand; see Rösch, B.; Gentner, T. X.; Eyselein, J.; Langer, J.; Elsen, H.; Li, W.; Harder, S. (2021). "Strongly reducing magnesium(0) complexes". Nature. 592 (7856): 717–721. Bibcode:2021Natur.592..717R. doi:10.1038/s41586-021-03401-w. PMID 33911274. S2CID 233447380
^Bernath, P. F.; Black, J. H. & Brault, J. W. (1985). "The spectrum of magnesium hydride" (PDF). Astrophysical Journal. 298: 375. Bibcode:1985ApJ...298..375B. doi:10.1086/163620.. See also Low valent magnesium compounds.
^Rumble, p. 12.137
^Rumble, p. 12.28
^Rumble, p. 4.70
^Gschneider, K. A. (1964). Physical Properties and Interrelationships of Metallic and Semimetallic Elements. Solid State Physics. Vol. 16. p. 308. doi:10.1016/S0081-1947(08)60518-4. ISBN 9780126077162.
^ abcRumble, p. 4.19
^Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae.
^Cite error: The named reference Abundance was invoked but never defined (see the help page).
^Anthoni, J Floor (2006). "The chemical composition of seawater". seafriends.org.nz.
^ abCite error: The named reference nih was invoked but never defined (see the help page).
Cite error: There are <ref group=lower-alpha> tags or {{efn}} templates on this page, but the references will not show without a {{reflist|group=lower-alpha}} template or {{notelist}} template (see the help page).
Magnesium is a chemical element; it has symbol Mg and atomic number 12. It is a shiny gray metal having a low density, low melting point and high chemical...
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Magnesium phosphate is a general term for salts of magnesium and phosphate appearing in several forms and several hydrates: Monomagnesium phosphate (Mg(H2PO4)2)...
Magnesium oil (also referred to as transdermal magnesium, magnesium hexahydrate) is a compound of magnesium chloride dissolved in six molecules of water...
Magnesium (Mg) is a mineral found naturally in the human body and in animal and plant-based foods, beverages, dietary supplements, and some medicines...
Anhydrous magnesium acetate has the chemical formula Mg(C2H3O2)2 and in its hydrated form, magnesium acetate tetrahydrate, it has the chemical formula...
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Magnesium nitrate refers to inorganic compounds with the formula Mg(NO3)2(H2O)x, where x = 6, 2, and 0. All are white solids. The anhydrous material is...
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Magnesium bicarbonate or magnesium hydrogencarbonate, Mg(HCO3)2, is the bicarbonate salt of magnesium. It can be formed through the reaction of dilute...
Magnesium azide is an inorganic chemical compound with the formula Mg(N3)2. It is composed of the magnesium cation (Mg2+) and the azide anions (N−3)....
Magnesium alloys are mixtures of magnesium (the lightest structural metal) with other metals (called an alloy), often aluminium, zinc, manganese, silicon...