Magnesium is a chemical element with the 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, it occurs naturally only in combination with other elements and it almost always has an oxidation state of +2.
Symbol: Mg
Atomic mass: 24.305 u
Atomic number: 12
Electronegativity: 1.31
Electron configuration: [Ne] 3s2
Density: 1.738 g/cm³
Discoverers: Humphry Davy, Joseph Black
List of facts
Magnesium is a chemical element with the symbol Mg
Magnesium has the atomic number 12
The name magnesium originates from the Greek word for locations related to the tribe of the Magnetes, either a district in Thessaly called Magnesia or Magnesia ad Sipylum, now in Turkey.
It is a shiny gray metal having a low density, low melting point, and high chemical reactivity
Like the other alkaline earth metals, it occurs naturally only in combination with other elements
Magnesium is the eighth most abundant element in the Earth's crust
Magnesium is the fourth most common element on the Earth
Magnesium makes 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
This element is the eleventh most abundant element by mass in the human body and is essential to all cells and some 300 enzyme
Elemental magnesium is a gray-white lightweight metal, two-thirds the density of aluminum
Magnesium has the lowest melting of 650 °C and the lowest boiling point of 1,090 °C of all the alkaline earth metals
Milk of Magnesia, which works as a laxative and to treat indigestion, is a compound of magnesium, hydrogen, and oxygen molecules
Epsom salts are magnesium sulfate
Magnesium is produced by large stars when they combine helium and neon.
It is found in large deposits of magnesite, dolomite, and other minerals, and in mineral waters, where magnesium ion is soluble.
Although magnesium is found in more than 60 minerals, only dolomite, magnesite, brucite, carnallite, talc, and olivine are of commercial importance.
China controls eighty percent of the world's magnesium production.
Magnesium is the third-most-commonly-used structural metal, following iron and aluminium
World production was approximately 1,100 kt in 2017, with the bulk being produced in China (930 kt) and Russia (60 kt)
The metal itself was first isolated by Sir Humphry Davy in England in 1808.
Spices, nuts, cereals, cocoa, and vegetables are rich sources of magnesium.
Green leafy vegetables such as spinach are also rich in magnesium.[64]
Beverages rich in magnesium are coffee, tea, and cocoa
In the UK, the recommended daily values for magnesium are 300 mg for men and 270 mg for women
In the U.S. the Recommended Dietary Allowances are 400 mg for men ages 19–30 and 420 mg for older; for women 310 mg for ages 19–30 and 320 mg for older
An adult body has 22–26 grams of magnesium
Plants require magnesium to synthesize chlorophyll, essential for photosynthesis.
Magnesium borate, magnesium salicylate, and magnesium sulfate are used as antiseptics.
Magnesium hydroxide, suspended in water, is used in milk of magnesia antacids and laxatives.
Magnesium has three stable isotopes: 24Mg, 25Mg, and 26Mg
About 79 percent of Mg is 24Mg.
25Mg has 10 percent natural abundance and 26Mg has 11 percent natural abundance
In the body, 60% is found in the skeleton, 39% is found in the muscle cells, and 1% is extracellular.
Of the intracellular magnesium, twenty percent of that amount is found in the skeletal muscle cells.
Properties of Magnesium
Physical properties |
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Phase at STP | solid | ||||||||||||||
Melting point | 923 K (650 °C, 1202 °F) | ||||||||||||||
Boiling point | 1363 K (1091 °C, 1994 °F) | ||||||||||||||
Density (near r.t.) | 1.738 g/cm3 | ||||||||||||||
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[2] J/(mol·K) | ||||||||||||||
Vapor pressure
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Atomic properties |
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Oxidation states | 0, +1, +2 (a strongly basic oxide) | ||||||||||||||
Electronegativity | Pauling scale: 1.31 | ||||||||||||||
Ionization energies |
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Atomic radius | empirical: 160 pm | ||||||||||||||
Covalent radius | 141±7 pm | ||||||||||||||
Van der Waals radius | 173 pm | ||||||||||||||
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Other properties |
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Natural occurrence | primordial | ||||||||||||||
Crystal structure | hexagonal close-packed (hcp) | ||||||||||||||
Speed of sound thin rod | 4940 m/s (at r.t.) (annealed) | ||||||||||||||
Thermal expansion | 24.8 µm/(m⋅K) (at 25 °C) | ||||||||||||||
Thermal conductivity | 156 W/(m⋅K) | ||||||||||||||
Electrical resistivity | 43.9 nΩ⋅m (at 20 °C) | ||||||||||||||
Magnetic ordering | paramagnetic | ||||||||||||||
Molar magnetic susceptibility | +13.1×10−6 cm3/mol (298 K) | ||||||||||||||
Young's modulus | 45 GPa | ||||||||||||||
Shear modulus | 17 GPa | ||||||||||||||
Bulk modulus | 35.4 GPa | ||||||||||||||
Poisson ratio | 0.290 | ||||||||||||||
Mohs hardness | 1–2.5 | ||||||||||||||
Brinell hardness | 44–260 MPa | ||||||||||||||
CAS Number | 7439-95-4 |