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Magnesium vs. Magnesium Oxide: What's the Difference?

Edited by Aimie Carlson || By Janet White || Updated on October 21, 2023
Magnesium is a silver-white metallic element, while magnesium oxide is a white compound formed when magnesium reacts with oxygen.

Key Differences

Magnesium is a chemical element, symbolized as Mg on the periodic table, and is a shiny gray solid under standard conditions. Magnesium oxide, on the other hand, is a chemical compound comprised of magnesium and oxygen, represented by the chemical formula MgO.
In terms of physical properties, magnesium is a metal with good electrical conductivity, often used in alloy production. Magnesium oxide is an ionic compound, typically found as a white powder and is not conductive like its metallic counterpart.
Magnesium is highly reactive and can combust if exposed to open air, especially when powdered. Magnesium oxide, being the result of magnesium's reaction with oxygen, is already in its combusted form and does not share this reactivity.
In the human body, magnesium plays critical roles in many cellular processes and is considered an essential mineral for health. Magnesium oxide, however, is often consumed as a dietary supplement or antacid, benefiting from the magnesium content but serving different purposes than elemental magnesium.
From a commercial perspective, magnesium finds its use in the production of fireworks, flares, and several alloys due to its lightness and strength. Magnesium oxide is utilized in refractories, as an insulator in industrial cables, and in the medical field as mentioned above.

Comparison Chart


Elemental metal
Chemical compound

Chemical Symbol/Formula


Physical State

Shiny gray solid metal
White powder


Highly reactive with air and water
Stable and non-reactive

Primary Uses

Alloys, fireworks, flares
Dietary supplement, antacid, refractories

Magnesium and Magnesium Oxide Definitions


A mineral that plays a vital role in muscle function and bone health.
It's recommended to have magnesium-rich foods in our diet.

Magnesium Oxide

The product formed when magnesium is combusted in the presence of oxygen.
When magnesium ribbon is burned in air, magnesium oxide is produced.


A metal that burns with a bright white flame when ignited.
Magnesium strips are used in science labs to demonstrate combustion reactions.

Magnesium Oxide

A material used as an insulator in industrial cabling and in refractories.
Because of its insulating properties, magnesium oxide is used in some types of industrial heating elements.


A light, silver-white, ductile, and malleable metallic element.
Due to its lightness, magnesium is often used in alloying aluminum.

Magnesium Oxide

A substance commonly used as an antacid to neutralize stomach acid.
People sometimes take magnesium oxide tablets for indigestion.


A chemical element with the symbol Mg and atomic number 12.
Magnesium is essential for various biochemical reactions in the body.

Magnesium Oxide

A white powdery compound with the chemical formula MgO.
Magnesium oxide is often used as a filler in some bricks.


An essential element used in the production of a variety of commercial products.
Because of its properties, magnesium is used in the manufacturing of laptops and

Magnesium Oxide

An ionic compound resulting from the combination of magnesium and oxygen.
Magnesium oxide has a high melting point due to its ionic bonds.


A light, silvery-white, moderately hard metallic element that in ribbon or powder form burns with a brilliant white flame. Obtained chiefly from magnesite, dolomite, and bodies of salt water, it is used in structural alloys, pyrotechnics, flash photography, and incendiary bombs. Atomic number 12; atomic weight 24.305; melting point 650°C; boiling point 1,090°C; specific gravity 1.738 (at 20°C); valence 2. See Periodic Table.


The chemical element (symbol Mg) with an atomic number of 12. It is a light, easily flammable, silvery-white alkaline earth metal.


A light silver-white metallic element of atomic number 12, malleable and ductile, quite permanent in dry air but tarnishing in moist air. It burns, forming (the oxide) magnesia, with the production of a blinding light (the so-called magnesium light) which is used in signaling, in pyrotechny, or in photography where a strong actinic illuminant is required. Its compounds occur abundantly, as in dolomite, talc, meerschaum, etc. Symbol Mg. Atomic weight, 24.305. Specific gravity, 1.75.


A light silver-white ductile bivalent metallic element; in pure form it burns with brilliant white flame; occurs naturally only in combination (as in magnesite and dolomite and carnallite and spinel and olivine)


Is magnesium essential for the human body?

Yes, magnesium is crucial for many cellular processes and overall health.

Can magnesium easily burn?

Yes, magnesium can ignite and burn with a bright white flame when exposed to a flame.

For what medical purposes is magnesium oxide used?

Magnesium oxide is often used as a dietary supplement and antacid.

What is magnesium's place on the periodic table?

Magnesium has the atomic number 12 and is symbolized as Mg.

Are magnesium and magnesium oxide found naturally?

Magnesium is found in the earth's crust and in seawater. Magnesium oxide can form naturally when magnesium-rich rocks oxidize.

Is magnesium oxide an elemental metal?

No, magnesium oxide is a compound made of magnesium and oxygen.

Can magnesium oxide be formed in any reaction involving magnesium?

Magnesium oxide is primarily formed when magnesium reacts with oxygen, especially during combustion.

What color is magnesium oxide?

Magnesium oxide is a white powder or crystalline solid.

Why is magnesium used in fireworks?

Magnesium burns with a bright white flame, making it ideal for fireworks.

Which is heavier, magnesium or magnesium oxide?

Magnesium oxide is heavier because it includes the weight of both magnesium and oxygen.

Are there any dietary sources rich in magnesium?

Yes, foods like spinach, nuts, and whole grains are rich in magnesium.

How is magnesium oxide produced industrially?

It's often produced by calcining magnesite or by treating magnesium chloride with lime.

Is magnesium oxide safe to consume?

Yes, in appropriate amounts, magnesium oxide is consumed as a supplement.

What is the appearance of magnesium?

Magnesium is a shiny gray solid metal.

How does magnesium react with water?

Magnesium reacts with water to produce magnesium hydroxide and hydrogen gas.

Is magnesium oxide soluble in water?

Magnesium oxide is sparingly soluble in water.

What role does magnesium play in photosynthesis?

Magnesium is a central atom in the chlorophyll molecule, which is vital for photosynthesis.

What are the primary industrial uses of magnesium oxide?

Magnesium oxide is used in refractories, as an insulator in cables, and in various chemical processes.

Can magnesium oxide be used to treat heartburn?

Yes, magnesium oxide can neutralize stomach acid and is often used as an antacid.

Can magnesium oxide be used in agriculture?

Yes, magnesium oxide is sometimes used to correct magnesium-deficient soils.
About Author
Written by
Janet White
Janet White has been an esteemed writer and blogger for Difference Wiki. Holding a Master's degree in Science and Medical Journalism from the prestigious Boston University, she has consistently demonstrated her expertise and passion for her field. When she's not immersed in her work, Janet relishes her time exercising, delving into a good book, and cherishing moments with friends and family.
Edited by
Aimie Carlson
Aimie Carlson, holding a master's degree in English literature, is a fervent English language enthusiast. She lends her writing talents to Difference Wiki, a prominent website that specializes in comparisons, offering readers insightful analyses that both captivate and inform.

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