Magnesium oxide melting point

This week, Simon Cotton is lighting things up.

© Science Photo Library

Simon Cotton

Many British people thinking back to their schooldays will remember seeing the burning of magnesium ribbon, possibly even doing the experiment themselves. You may recall the instruction of your teacher to ‘look away’ or ‘not to stare at the bright light’ or ‘put your hands over your eyes’. Then the piece of magnesium would be lowered into the Bunsen flame, and would soon ignite. You’d be looking away by now, but would be conscious of a blinding white light – which is why magnesium is used in signal flares. After it finished burning, you’d be left with a white ash, a solid that easily broke up to a powder. This powder is mainly magnesium oxide, MgO.

The hot magnesium supplies enough energy for oxygen molecules to split up, breaking the very strong O=O double bond. Each magnesium atom gives two electrons to an oxygen atom, so magnesium oxide is made of magnesium ions, Mg2+, and oxide, O2– ions.

You’ll notice I said mainly MgO. Magnesium burns so vigorously that there is even enough energy to break the even stronger N–N triple bond in molecules of nitrogen and form magnesium nitride, formula Mg3N2, which is made of magnesium ions, Mg2+, and nitride, N3– ions.

To make pure MgO, one way is to burn magnesium ribbon in pure oxygen, but metallic magnesium is quite expensive. A better and cheaper way is to heat magnesium carbonate or magnesium nitrate until they decompose.

‘Many of you will recognise the blue glass bottles bearing the label ‘milk of magnesia’, which is a suspension of magnesium hydroxide in water’

Magnesium oxide is a compound of a metal with a non-metal, so – as you would expect – it is held together with ionic bonds. It has the same structure as NaCl but because it is made of Mg2+ and O2– ions, rather than the singly charged Na+ and Cl– ions, there is a much stronger attraction between the ions. This means it takes a lot more energy to pull them apart, so MgO has a melting point of 3125K, nearly three times the melting point of 1074K for sodium chloride. This strong attraction between the ions is also responsible for magnesium oxide being much less soluble than sodium chloride.

Because of its high melting point, magnesium oxide finds many uses which apply its refractory properties, so it can be used as a furnace lining and in crucibles. It is also used for fireproofing boarding for panelling walls.

Read electro-mechanical engineering blog
PacificCoast NutriLabs PacificCoast NutriLabs 500mg Magnesium Citrate, 1000mg Calcium, Free eBook, 120 Vegetarian Tablets
Health and Beauty (PacificCoast NutriLabs)
  • ALL-NATURAL MAGNESIUM CITRATE + CALCIUM: Our vegetarian formula has NO soy, NO gluten, NO artificial flavor or sweetener, NO preservatives, NO sugar, NO milk, NO...
  • CITRATE FORM: Unlike magnesium oxide, commonly sold in pharmacies, magnesium citrate is one of the most popular magnesium supplements available due to its value...
  • WITH CALCIUM: We ve formulated our PLATINUM Series Magnesium Citrate with 1mg of calcium to create the recommended 2:1 calcium/magnesium ratio to aid in the highest...
  • NO HUGE PILLS: While many magnesium supplements require you to take excessively large pills, our small tablet size and shape makes them easy to swallow.
  • BONUS FREE EBOOK: Order now to get our new eBook, The Magnesium Method, a $17.99 value, absolutely free. This short read will make an immediate, impactful difference...
MAGNESIUM CITRATE - 250 SMALL & EASY TO SWALLOW Tablets - includes FREE DOSAGE GUIDE. Highly Absorbable Supplement. Helps with Sleep, Anxiety, Migraines, and Leg Cramps.* Satisfaction Guaranteed.
Health and Beauty (Nuvari LIfe)
  • NO MORE HORSE PILLS! - Smaller 100mg coated tablets are EASIER TO SWALLOW than the typical over-sized pills of other brands. Circular Tablets are 12mm in diameter...
  • FREE SUPPLEMENT GUIDE - Helpful instructions for determining your unique magnesium needs*. Also includes helpful tips for getting the most out of your Magnesium...
  • NEW DissolvALL TECHNOLOGY: Special Formula Guarantees each tablet properly dissolves for maximum absorbency.
  • HYPOALLERGENIC: Contains NO soy, yeast, sugar, dairy, gluten, artificial colors, flavors, or preservatives. Our products are also Kosher and Halal, with no unnecessary...
  • 100% NO-QUESTIONS GUARANTEE! Your Satisfaction is our priority. Guaranteed to correct your Magnesium Deficiency or your money back. *This product is not intended...
Generic OTC Generic OTC Magnesium Oxide Tablets - 3 Bottles
Health and Beauty (Generic OTC)
  • Dietary supplement with various uses like heartburn, sour stomach, acid indigestion, or as a laxative
  • Three Bottles - Each bottle holds 120 - 400mg tablets
Young Phorever Young PHorever pHLush Powder 200g
Beauty (Young Phorever)
  • an excellent cleansing supplement designed to increase alkalinity and eliminate toxins and undigested matter within the Alimentary Canal
  • combines the power of magnesium oxide and other ingredients to act as a natural laxative
  • must alter our normal healthy internal chemistry before acids can weaken our organs and glands with toxicity, congestion, or poor nutrition and before our body parts...
Medline Medline Magnesium Oxide Tablets, 400 gm Bottle (2 Case)
BISS (Medline)
  • A dietary supplement for various uses.
  • Can be used to help relieve heartburn, sour stomach or acid indigestion;as a laxative for short-term emptying of the bowel; or as a dietary supplement when the amount...
Related Posts