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Names | |
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IUPAC name Magnesium oxide | |
Other names
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Identifiers | |
3D model (JSmol) | |
ChEMBL | |
ChemSpider | |
ECHA InfoCard | 100.013.793 |
EC Number |
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E number | E530 (acidity regulators, ...) |
KEGG | |
PubChem CID | |
RTECS number |
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UNII | |
CompTox Dashboard (EPA) | |
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Properties | |
MgO | |
Molar mass | 40.304 g/mol [1] |
Appearance | White powder |
Odor | Odorless |
Density | 3.6 g/cm3 [1] |
Melting point | 2,852 °C (5,166 °F; 3,125 K) [1] |
Boiling point | 3,600 °C (6,510 °F; 3,870 K) [1] |
Solubility | Soluble in acid, ammonia insoluble in alcohol |
Electrical resistivity | Dielectric [lower-alpha 1] |
Band gap | 7.8 eV [5] |
−10.2·10−6 cm3/mol [6] | |
Thermal conductivity | 45–60 W·m−1·K−1 [7] |
Refractive index (nD) | 1.7355 |
6.2 ± 0.6 D | |
Structure | |
Halite (cubic), cF8 | |
Fm3m, No. 225 | |
a = 4.212Å | |
Octahedral (Mg2+); octahedral (O2−) | |
Thermochemistry | |
Heat capacity (C) | 37.2 J/mol K [8] |
Std molar entropy (S⦵298) | 26.95 ± 0.15 J·mol−1·K−1 [9] |
Std enthalpy of formation (ΔfH⦵298) | −601.6 ± 0.3 kJ·mol−1 [9] |
Gibbs free energy (ΔfG⦵) | -569.3 kJ/mol [8] |
Pharmacology | |
A02AA02 ( WHO ) A06AD02 ( WHO ), A12CC10 ( WHO ) | |
Hazards | |
Occupational safety and health (OHS/OSH): | |
Main hazards | Metal fume fever, Irritant |
GHS labelling: | |
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Warning | |
H315, H319, H335 | |
P261, P264, P271, P273, P280, P302+P352, P304+P340, P305+P351+P338, P312, P333+P313, P337+P313, P362, P363, P391, P403+P233, P405 | |
NFPA 704 (fire diamond) | |
Flash point | Non-flammable |
NIOSH (US health exposure limits): | |
PEL (Permissible) | TWA 15 mg/m3 (fume) [10] |
REL (Recommended) | None designated [10] |
IDLH (Immediate danger) | 750 mg/m3 (fume) [10] |
Safety data sheet (SDS) | ICSC 0504 |
Related compounds | |
Other anions | Magnesium sulfide Magnesium selenide |
Other cations | Beryllium oxide Calcium oxide Strontium oxide Barium oxide |
Related compounds | Magnesium hydroxide Magnesium nitride |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). |
Magnesium oxide ( Mg O ), or magnesia, is a white hygroscopic solid mineral that occurs naturally as periclase and is a source of magnesium (see also oxide). It has an empirical formula of MgO and consists of a lattice of Mg2+ ions and O2− ions held together by ionic bonding. Magnesium hydroxide forms in the presence of water (MgO + H2O → Mg(OH)2), but it can be reversed by heating it to remove moisture.
Magnesium oxide was historically known as magnesia alba (literally, the white mineral from Magnesia), to differentiate it from magnesia nigra , a black mineral containing what is now known as manganese.
While "magnesium oxide" normally refers to MgO, the compound magnesium peroxide MgO2 is also known. According to evolutionary crystal structure prediction, [11] MgO2 is thermodynamically stable at pressures above 116 GPa (gigapascals), and a semiconducting suboxide Mg3O2 is thermodynamically stable above 500 GPa. Because of its stability, MgO is used as a model system for investigating vibrational properties of crystals. [12]
Pure MgO is not conductive and has a high resistance to electric current at room temperature. The pure powder of MgO has a relative permittivity inbetween 3.2 to 9.9 with an approximate dielectric loss of tan(δ) > 2.16x103 at 1kHz. [2] [3] [4]
Magnesium oxide is produced by the calcination of magnesium carbonate or magnesium hydroxide. The latter is obtained by the treatment of magnesium chloride MgCl
2 solutions, typically seawater, with limewater or milk of lime. [13]
Calcining at different temperatures produces magnesium oxide of different reactivity. High temperatures 1500 – 2000 °C diminish the available surface area and produces dead-burned (often called dead burnt) magnesia, an unreactive form used as a refractory. Calcining temperatures 1000 – 1500 °C produce hard-burned magnesia, which has limited reactivity and calcining at lower temperature, (700–1000 °C) produces light-burned magnesia, a reactive form, also known as caustic calcined magnesia. Although some decomposition of the carbonate to oxide occurs at temperatures below 700 °C, the resulting materials appear to reabsorb carbon dioxide from the air.[ citation needed ]
MgO is prized as a refractory material, i.e. a solid that is physically and chemically stable at high temperatures. It has the useful attributes of high thermal conductivity and low electrical conductivity. According to a 2006 reference book: [14]
By far the largest consumer of magnesia worldwide is the refractory industry, which consumed about 56% of the magnesia in the United States in 2004, the remaining 44% being used in agricultural, chemical, construction, environmental, and other industrial applications.
MgO is used as a refractory material for crucibles. It is also used as an insulator in heat-resistant electrical cable.
Among metal oxide nanoparticles, magnesium oxide nanoparticles (MgO NPs) have distinct physicochemical and biological properties, including biocompatibility, biodegradability, high bioactivity, significant antibacterial properties, and good mechanical properties, which make it a good choice as a reinforcement in composites. [15]
It is used extensively as an electrical insulator in tubular construction heating elements as in electric stove and cooktop heating elements. There are several mesh sizes available and most commonly used ones are 40 and 80 mesh per the American Foundry Society. The extensive use is due to its high dielectric strength and average thermal conductivity. MgO is usually crushed and compacted with minimal airgaps or voids.
MgO is one of the components in Portland cement in dry process plants.
Sorel cement uses MgO as the main component in combination with MgCl2 and water.
MgO has an important place as a commercial plant fertilizer [16] and as animal feed. [17]
It is a principal fireproofing ingredient in construction materials. As a construction material, magnesium oxide wallboards have several attractive characteristics: fire resistance, termite resistance, moisture resistance, mold and mildew resistance, and strength, but also a severe downside as it attracts moisture and can cause moisture damage to surrounding materials [18] [14]
Magnesium oxide is used for relief of heartburn and indigestion, as an antacid, magnesium supplement, and as a short-term laxative. It is also used to improve symptoms of indigestion. Side effects of magnesium oxide may include nausea and cramping. [19] In quantities sufficient to obtain a laxative effect, side effects of long-term use may rarely cause enteroliths to form, resulting in bowel obstruction. [20]
Magnesium oxide is used extensively in the soil and groundwater remediation, wastewater treatment, drinking water treatment, air emissions treatment, and waste treatment industries for its acid buffering capacity and related effectiveness in stabilizing dissolved heavy metal species.[ according to whom? ]
Many heavy metals species, such as lead and cadmium, are least soluble in water at mildly basic conditions (pH in the range 8–11). Solubility of metals increases their undesired bioavailability and mobility in soil and groundwater. Granular MgO is often blended into metals-contaminating soil or waste material, which is also commonly of a low pH (acidic), in order to drive the pH into the 8–10 range. Metal-hydroxide complexes tend to precipitate out of aqueous solution in the pH range of 8–10.
MgO is packed in bags around transuranic waste in the disposal cells (panels) at the Waste Isolation Pilot Plant, as a CO2 getter to minimize the complexation of uranium and other actinides by carbonate ions and so to limit the solubility of radionuclides. The use of MgO is preferred over CaO since the resulting hydration product (Mg(OH)
2) is less soluble and releases less hydration heat. Another advantage is to impose a lower pH value (about 10.5) in case of accidental water ingress into the dry salt layers, in contast to the more soluble Ca(OH)
2 which would create a higher pH of 12.5 (strongly alkaline conditions). The Mg2+
cation being the second most abundant cation in seawater and in rocksalt, the potential release of magnesium ions dissolving in brines intruding the deep geological repository is also expected to minimize the geochemical disruption. [21]
Inhalation of magnesium oxide fumes can cause metal fume fever. [33]
Lanthanum is a chemical element; it has symbol La and atomic number 57. It is a soft, ductile, silvery-white metal that tarnishes slowly when exposed to air. It is the eponym of the lanthanide series, a group of 15 similar elements between lanthanum and lutetium in the periodic table, of which lanthanum is the first and the prototype. Lanthanum is traditionally counted among the rare earth elements. Like most other rare earth elements, its usual oxidation state is +3, although some compounds are known with an oxidation state of +2. Lanthanum has no biological role in humans but is essential to some bacteria. It is not particularly toxic to humans but does show some antimicrobial activity.
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 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.
Zirconium is a chemical element; it has symbol Zr and atomic number 40. First identified in 1789, isolated in impure form in 1824, and manufactured at scale by 1925, pure zirconium is a lustrous transition metal with a greyish-white color that closely resembles hafnium and, to a lesser extent, titanium. It is solid at room temperature, ductile, malleable and corrosion-resistant. The name zirconium is derived from the name of the mineral zircon, the most important source of zirconium. The word is related to Persian zargun. Besides zircon, zirconium occurs in over 140 other minerals, including baddeleyite and eudialyte; most zirconium is produced as a byproduct of minerals mined for titanium and tin.
The alkaline earth metals are six chemical elements in group 2 of the periodic table. They are beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra). The elements have very similar properties: they are all shiny, silvery-white, somewhat reactive metals at standard temperature and pressure.
Calcium oxide, commonly known as quicklime or burnt lime, is a widely used chemical compound. It is a white, caustic, alkaline, crystalline solid at room temperature. The broadly used term lime connotes calcium-containing inorganic compounds, in which carbonates, oxides, and hydroxides of calcium, silicon, magnesium, aluminium, and iron predominate. By contrast, quicklime specifically applies to the single compound calcium oxide. Calcium oxide that survives processing without reacting in building products, such as cement, is called free lime.
Magnesium hydroxide is an inorganic compound with the chemical formula Mg(OH)2. It occurs in nature as the mineral brucite. It is a white solid with low solubility in water (Ksp = 5.61×10−12). Magnesium hydroxide is a common component of antacids, such as milk of magnesia.
Magnesium carbonate, MgCO3, is an inorganic salt that is a colourless or white solid. Several hydrated and basic forms of magnesium carbonate also exist as minerals.
Chlorine trifluoride is an interhalogen compound with the formula ClF3. It is a colorless, poisonous, corrosive, and extremely reactive gas that condenses to a pale-greenish yellow liquid, the form in which it is most often sold. It is famous for its extreme oxidation properties. The compound is primarily of interest in plasmaless cleaning and etching operations in the semiconductor industry, in nuclear reactor fuel processing, historically as a component in rocket fuels, and various other industrial operations owing to its corrosive nature.
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 hygroscopic, quickly forming the hexahydrate upon standing in air. All of the salts are very soluble in both water and ethanol.
Magnesium silicide, Mg2Si, is an inorganic compound consisting of magnesium and silicon. As-grown Mg2Si usually forms black crystals; they are semiconductors with n-type conductivity and have potential applications in thermoelectric generators.
Sorel cement is a non-hydraulic cement first produced by the French chemist Stanislas Sorel in 1867.
Aluminium fluoride is an inorganic compound with the formula AlF3. It forms hydrates AlF3·xH2O. Anhydrous AlF3 and its hydrates are all colorless solids. Anhydrous AlF3 is used in the production of aluminium. Several occur as minerals.
Soda–lime glass, also called soda–lime–silica glass, is the most prevalent type of glass, used for windowpanes and glass containers for beverages, food, and some commodity items. Some glass bakeware is made of soda-lime glass, as opposed to the more common borosilicate glass. Soda–lime glass accounts for about 90% of manufactured glass.
Thallium(I) bromide is a chemical compound of thallium and bromine with a chemical formula TlBr. This salt is used in room-temperature detectors of X-rays, gamma-rays and blue light, as well as in near-infrared optics.
Thallium(I) chloride, also known as thallous chloride, is a chemical compound with the formula TlCl. This colourless salt is an intermediate in the isolation of thallium from its ores. Typically, an acidic solution of thallium(I) sulfate is treated with hydrochloric acid to precipitate insoluble thallium(I) chloride. This solid crystallizes in the caesium chloride motif.
Thallium(I) iodide is a chemical compound with the formula . It is unusual in being one of the few water-insoluble metal iodides, along with , , , , and .
Aluminium diboride (AlB2) is a chemical compound made from the metal aluminium and the metalloid boron. It is one of two compounds of aluminium and boron, the other being AlB12, which are both commonly referred to as aluminium boride.
Hafnium silicate is the hafnium(IV) salt of silicic acid with the chemical formula of HfSiO4.
Barium perchlorate is a powerful oxidizing agent, with the formula Ba(ClO4)2. It is used in the pyrotechnic industry.
Magnesium hydroxychloride is the traditional term for several chemical compounds of magnesium, chlorine, oxygen, and hydrogen whose general formula xMgO·yMgCl2·zH2O, for various values of x, y, and z; or, equivalently, Mgx+y(OH)2xCl2y(H2O)z−x. The simple chemical formula that is often used is Mg(OH)Cl, which appears in high school subject, for example.Other names for this class are magnesium chloride hydroxide, magnesium oxychloride, and basic magnesium chloride. Some of these compounds are major components of Sorel cement.