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Magnesium Oxide

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What is Magnesium Oxide?

When we read the term MgO the first question that comes to our mind is What is MgO? It is a very simple chemical formula that we can remember easily. This easy formula is a very important inorganic compound which is known as Magnesium Oxide. MgO is alkaline earth metal oxide. The magnesium oxide formula is one of the easiest formulas for students to remember and use during examinations or exams. Let's have a look at the compound before we go into the recipe. Magnesium oxide, often known as magnesia, is an alkaline earth metal oxide that is mostly formed by calcining specific minerals. It is a solid that is both physically and chemically stable at high temperatures. As a result, refractory materials frequently use it.


Magnesium Oxide Formula and Structure

Magnesium Oxide is also known as magnesia and is a magnesium-rich mineral. Furthermore, the preparation reaction is reversible, and the components can be easily recovered by simply heating the molecule. Magnesia Alba (the white mineral of magnesia) was the term given to it in the past to distinguish it from Magnesia Negra (the black mineral that contains manganese). According to the evolutionary crystal structure prediction, it is thermodynamically stable at pressures over 116 GPa (gigapascals), while a semiconducting suboxide Mg₂O₂ is thermodynamically stable at pressures above 500 GPa. We also employ magnesium oxide as a model system for investing crystal vibrational characteristics because of its stability.


Magnesium oxide has the chemical and molecular formula MgO. It has a molecular weight of 40.304 g/mol and a molar mass of 40.304 g/mol. It also has the empirical formula Mgo and is made up of the lattice magnesium cation Mg⁺₂ and the oxygen anion O₂, which are kept together by an ionic bond.


It also creates magnesium hydroxide (Mg(OH)₂) in the presence of water. This process, however, is reversible, and the elements can be obtained by separating the moisture.


MgO structure or magnesium oxide structure is halite crystal structure.


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Occurrence of Magnesium Oxide

It is found in nature as periclase, which is the most abundant source of magnesium. It can also be prepared in laboratories, enterprises, and research facilities.


Preparation of Magnesium Oxide

Magnesium oxide can be made by calcining magnesium hydroxide or magnesium carbonate. The latter, on the other hand, can be achieved by combining magnesium chloride solutions, commonly saltwater, with lime:


\[Ca(OH)_{2}\] + \[Mg^{+}_{2}\] \[\rightarrow\] \[Ca(OH)_{2}\] + \[Ca^{+}_{2}\]


Furthermore, calcination at various temperatures yields magnesium oxide with varying reactivity. High temperatures, such as 1500-2000⁰C, reduce the accessible surface area, resulting in dead burnt magnesia, an inert form that we employ as a refractory.


Furthermore, calcination at a lower temperature, such as 700-1000⁰C, creates light burn magnesia, a reactive form known as caustic calcined magnesia, whereas calcination at a higher temperature, such as 1000-1500⁰C, produces hard burn magnesia with restricted reactivity.


While some carbonate decays to oxide at temperatures below 700⁰C, the materials that result emerge to reabsorb carbon dioxide from the air.


Properties of Magnesium Oxide

Magnesium oxide is a white powder that has no odour. It has a density of 3.6 grammes per cubic centimetre. Furthermore, its melting temperature is 2852⁰C and its boiling point is 3600⁰C. It is soluble in acid and ammonia, as well as water, where it generates magnesium hydroxide. It is, nevertheless, insoluble in alcohol. The heat capacity is \[\frac{37.2 J}{mol K}\] , and the refractive index is 1.7355. The thermal conductivity is \[\frac{4560 W}{mK}\] .


If we talk about magnesium oxide reaction with water then we will get to know that magnesium hydroxide is formed when magnesium oxide combines with ionised water. This is a two-step reaction. This reaction occurs at a much higher temperature than room temperature, around 120⁰C, and can be stopped by reheating magnesium hydroxide. Magnesium oxide in water gives magnesium hydroxide.


Uses of Magnesium Oxide

Magnesium oxide is used as an antacid, magnesium supplement, and a short-term laxative to treat heartburn and dyspepsia. It is also used to alleviate indigestion problems. Nausea and cramps are two possible side effects of magnesium oxide. Long-term use in amounts sufficient to provide a laxative effect can result in enteroliths, which can cause intestinal blockage.


It functions as an anti-caking agent in foods. The US Food and Drug Administration recognises it for cacao goods, canned peas, and frozen desserts. E530 is the E number assigned to it.


Because of its good diffusing and reflecting capabilities, it was traditionally employed as a reference white color in colourimetry. To make an integrating sphere, it can be smoked onto the surface of an opaque material.


It's widely employed in tubular construction heating components as an electrical insulator. According to the American Foundry Society, there are numerous mesh sizes available, with 40 and 80 mesh being the most typically utilised. Because of its strong dielectric strength and average thermal conductivity, it is widely used. MgO is typically crushed and compacted to ensure that there are no air gaps or spaces. Aluminium oxide was also utilised in the electrical heating business, but it is no longer used.


For the N-protection of amines and amides, as a reagent in the installation of the carboxy-benzyl (Cbz) group using benzyl chloroformate in EtOAc. It's also utilised in heat-resistant electrical cable as an insulator. By transforming [clarification needed] the mechanism of crack propagation at the nanoscale, MgO doping has been shown to efficiently restrict grain growth in ceramics and improve their fracture toughness. At the Waste Isolation Pilot Plant, MgO is packed around transuranic waste to regulate radioactive solubility. MgO is used as a commercial plant fertiliser as well as animal feed.

FAQs on Magnesium Oxide

1.What are the chemical properties of magnesium oxide?

Magnesium oxide is a white powder in appearance. Some important chemical properties are listed below.

  • The melting point of magnesium oxide is 2,852° C.

  • The boiling point of magnesium oxide is 3600° C.

  • The Density of magnesium oxide is \[\frac{3.58 g}{cm^3}\].

2.What are some important uses of MgO?

There are some important uses of MgO-

  • In dry process plants, MgO is one of the components in Portland cement.

  • Because of its acid buffering ability and related effectiveness in stabilising dissolved heavy metal species, magnesium oxide is widely employed in soil and groundwater remediation, wastewater treatment, drinking water treatment, air pollution treatment, and waste treatment industries.

  • Many heavy metals, such as lead and cadmium, are most soluble in water when the pH is acidic (below 6) as well as when the pH is high (above 11). Metal soluble impacts species bioavailability as well as movement in soil and groundwater systems. Because most metal species are harmful to humans in certain quantities, it's critical to keep metal bioavailability and mobility to a minimum.