magnesium oxide


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magnesium oxide:

see magnesiamagnesia,
common name for the chemical compound magnesium oxide, MgO. It occurs as colorless, cubic crystals. It is refractory, melting at about 2,800°C;. It is very slightly soluble in pure water but is soluble in acids and solutions of ammonium salts.
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Magnesium Oxide

 

MgO, colorless crystals. Density, 3.58 g/cm3; melting point, 2800°C; boiling point, 3600°C. Magnesium oxide exhibits marked volatility at 2000°C. It is poorly soluble in water (6.2 ×10-4 g per 100 g H2O at 20°C). In the microcrystalline state (fine white powder), amorphous MgO absorbs water vapor and CO2 from the air to form Mg(OH)2 and MgCO3; it reacts readily with acids. Strongly calcined magnesium oxide loses its ability to combine with water and dissolve in acids.

Magnesium oxide occurs naturally as the rare mineral periclase. It is prepared industrially by calcination of magnesite and dolomite, as well as by the thermal dissociation of magnesium sulfate and basic magnesium carbonate, 3MgCO3.Mg(OH)2.3H2O. The properties of the commercial product, calcined magnesia, depend on the conditions of preparation, and the grades of the product are differentiated by apparent density (lightness), sorption, and chemical activity. Heavy magnesium oxides are used in the manufacture of refractories; lighter oxides are used in the preparation of magnesia cements and construction materials; and the lightest oxides are used to refine petroleum products and as fillers in the rubber industry. In medicine, magnesium oxide is prescribed for internal use as an alkali to counteract increased gastric acidity, and in cases of acid poisoning it has a mild laxative effect.

magnesium oxide

[mag′nē·zē·əm ′äk‚sīd]
(inorganic chemistry)
MgO A white powder that (depending on the method of preparation) may be light and fluffy, or dense; melting point 2800°C; insoluble in acids, slightly soluble in water; used in making refractories, and in cosmetics, pharmaceuticals, insulation, and medicine.
References in periodicals archive ?
Unlike conventional blocks, the strength of carbonized blocks is based on the chemical interaction among magnesium oxide, water, and carbon dioxide (solid, liquid, and gas phases), so we should have specific requirements for the moisture content, porosity, saturation, and initial strength of the block.
Then magnesium oxide, aluminum oxide, and phosphoric acid fire retardants of 10,20, and 30% composites were investigated.
The figure shows that the inhibition zone increases with increase of the concentration of magnesium oxide nanoparticles, this behavior attributed to the metal oxides carry the positive charge while the microorganisms carry negative charges; this causes electromagnetic attraction between microorganisms and the metal oxides which leads to oxidization and finally death of microorganisms.
In this study, we report the effect of calcium carbonate and magnesium oxide as support materials in the synthesis of CNTs using Fe/Co catalysts by thermal CCVD of acetylene gas.
Chandrappa, "Mesoporous nanocrystalline magnesium oxide for environmental remediation," Microporous and Mesoporous Materials, vol.
"For decades it was believed that MgO is the only thermodynamically stable magnesium oxide, and it was widely believed to be one of the main materials of the interiors of the Earth and other planets," said Qiang Zhu, the lead author of this paper and a postdoctoral student in the Oganov laboratory.
Statistically non-significant decreases in migraine index and migraine days in the magnesium oxide group were reported.
Less than 10 years ago, a study showed that a silica lining also was reduced by magnesium and magnesium sulfide from treated iron returns, but when oxygen is stripped from silica by magnesium or magnesium sulfide to form magnesium oxide, virtually no loss of lining material occurs.
Magnesium oxide (MgO) has many applications in pharmaceutical, cosmetic and food industry.
EFFECT OF MAGNESIUM OXIDE (Mgo) ADDITION IN DIETS FOR LACTATING HOLSTEIN COWS
Some chapter topics include formation of biaxial crystalline texture by oblique ion bombardment, inclined substrate deposition of biaxially textured magnesium oxide films, and ion-beam assisted pulsed laser deposition of textured transition-metal nitride films.
Starting in the early 1940s, Norton Co., now owned by Saint-Gobain Corp., manufactured refractory products from boron, beryllium, uranium, thorium, and magnesium oxide for the Atomic Energy Commission.