Chemistry Formulas

Magnesium Oxide Formula

Magnesium Oxide

Magnesium Oxide Formula- We also know it by the name of magnesia and is a source of magnesium. Furthermore, its preparation reaction is reversible and we can easily get the elements back simply by heating the compound. Historically, we know it by the name Magnesia Alba (the white mineral of magnesia), to distinguish it from magnesia Negra a black mineral that contains what we know as manganese.

Magnesium Oxide Formula

It is thermodynamically stable at a pressure above 116 GPa (gigapascals), and a semiconducting suboxide \( Mg_{3}O_{2} \) is thermodynamically stable above 500 GPa in accordance with the evolutionary crystal structure prediction. Moreover, due to the stability of magnesium oxide, we use it as a model system for investing vibrational properties of crystals.

Magnesium Oxide Formula and Structure

The chemical and molecular formula of magnesium oxide is MgO. Its molecular weight or molar mass is 40.304 g/mol. In addition, it has an empirical formula of MgO and consists o lattice magnesium cation \( Mg^{2+} \) and oxygen anion \( O^{2-} \) which held together by an ionic bond.

Furthermore, in the presence of water, it forms magnesium hydroxide ( \( Mg(OH)_{2} \) ). However, this reaction is reversible and we can obtain the elements by separating the moisture.

Occurrence of Magnesium Oxide

In nature, it occurs in mineral form as periclase, which is the largest source of magnesium. Also, we can also prepare it in laboratories, industries, and research centers.

Preparation of Magnesium Oxide

We can prepare magnesium oxide by calcination of magnesium hydroxide or magnesium carbonate. However, the last can be attained by the action of magnesium chloride solutions, usually seawater, with lime:

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

Besides, calcination at diverse temperatures produces magnesium oxide of different reactivity. At high temperatures like \( 1500 – 2000^{o} C \) diminish the available surface area and produces dead burn magnesia an unreactive form that we use as a refractory.

In addition, calcination temperature \( 1000 – 1500^{o} C \) produces hard burn magnesia whose reactivity is limited, and calcination at a lower temperature such as \( 700 -1000^{o} C \) it produces light burn magnesia, a reactive form that we know as caustic calcined magnesia.

While some decay of the carbonate to oxide occurs at temperatures below \( 700^{o} C \) whose resulting materials emerge to reabsorb carbon dioxide from the air.

Properties of Magnesium Oxide

Magnesium oxide appears as a white powder that is odorless. Its density is \( 3.6 g/cm^{3} \). Moreover, its boiling point is \( 3600^{o} C \) and the melting point is 2852^{o} C \). It is soluble in acid, ammonia, and highly soluble in water where it produces magnesium hydroxide. However, it is insoluble in alcohol. Its refractive index is 1.7355 and thermal conductivity is \( 45-60 W \cdot m^{-1} \cdot K^{-1} \) and the heat capacity is 37.2 J/mol K.

Uses of Magnesium Oxide

We use it as a refractory material i.e. a solid i.e. chemically and physically stable at high temperatures. In addition, it has two useful qualities: low electrical conductivity and high thermal conductivity. We use it as a food additive which is an anticaking agent whose E number is E530. Extensively we use it as an electrical insulator in tubular construction heating elements. Also, we use it as an insulator in heat-resistant electrical cable.

Safety and health hazards of magnesium oxide

It causes irritation in eyes, and respiratory tract and allergic reaction on skin. Also. In aquatic life, it has very long-lasting and very toxic effects.

Solved Example for You

Question: Is magnesium oxide stable?

Answer: At high temperature like \( 1500 – 2000^{o} C \) it is unreactive and temperature below it, is slightly reactive and reactive.

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