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Magnesium

June 24, 2012

Well magnesium is more interesting than I thought. She may be small but she is awesome. Magnesium (Mg) has been known since ancient times but wasn’t isolated as a pure metal until 1831 by Sir Humphrey Davy. She got her name from where she was found in Magnesia (now part of Greece) as one of two black minerals. The minerals were thought to be male and female. The female mineral, which was used to decolourise glass and wasn’t magnetic, unlike her male counterpart, was named Magnes, later changed to Magnesia and even later found to be Magnesium Oxide.

Magnesium is very very talented but occasionally lets her enthusiasm for showing off get out of hand. It isn’t really Magnesium’s fault as she is being egged on by oxygen. Although magnesium is unreactive when you compare it to lithium or sodium it does have a habit of catching fire at fairly low temperatures and then burning at up to 3000 degrees Celsius. Most of us remember burning strips of magnesium ribbon and being impressed with the bright white flame. This intense reaction between magnesium and oxygen has made magnesium an ideal choice for fireworks (magnesium is the sparkly bit of a sparkler) and flares and was once the flash bit of flash photography.

The low density of magnesium metal has made it an ideal choice for use in lightweight alloys. Combined with aluminium it makes super lightweight alloys used in cars and spacecraft. Magnesium is a strong metal comparable to aluminium but is about two thirds the density of aluminium.  The use of magnesium in alloys has not been without problems. One racing team’s attempts to lower the weight of their car  resulted in an horrific fire at Le Mans which was only made worse by officials pouring water on the flames in the mistaken belief that they were helping. Magnesium-aluminium alloy is still used, safely, is some engine components and for wheels on your car.

Magnesium is one of the few elements that we can taste but her sour flavour and laxative properties make it an unlikely ice-cream flavour. Which leads me to a story about cows and bath salts. In 1618 a farmer was encouraging his herd of cows to drink from a certain well near the English town of Epsom. The cows refused the water and when the farmer tried it for himself he found it tasted sour. On the plus side the farmer also found that the water caused scratches and cuts on his hands to heal quicker. The key component of the water was magnesium sulfate or Epsom Salts.

Magnesium has many important biological functions and we need about 0.3 grams every day to maintain the huge number of processes magnesium is involved with inside our cells. Of the 24 grams of magnesium in you body about 9 of them are inside your cells attached to over 300 different enzymes. Magnesium is essential to all living organisms! Yup, all of them. And do you see magnesium bragging about it?

But that isn’t even the whole story. No. Magnesium hides her, admittedly very bright, light under a bush(el). Specifically in the chlorophyll in the bushel’s leaves. Chlorophyll is perhaps one of the most important chemical compounds on the planet and has magnesium as its heart. Chlorophyll allows plants and algae to absorb energy from light. It gives us pretty much all the energy we use from food to fuel and keeps our planet habitable. Pretty impressive for such a relatively simple molecule and a process humans are still struggling to mimic in the lab.

Next time it’s cake decorations and ancient Greek myths. It’s aluminium (with two i’s).

@RotwangsRobot

Image by @SciCommStudios

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