Magnesium

Magnesium, Mg, is a silvery metallic alkaline earth element belonging to Group IIa of the periodic table.

Discovery

Magnesium was discovered by Bussy in 1828AD.

Magnesium was first isolated by Sir Humphery Davy in 1808AD as an impure metal.

Magnesium is found as its oxide, being a constituent of rocks in different ore forms.

In igneous rocks, it occurs as olivine, (MgFe)2SiO4.
In sedimentary rocks, it occurs as the carbonate, magnesite, and as the mixed carbonate, dolomite.

Magnesium also occurs as soluble salts including epsom salts, which is found in mineral waters and in hard waters.

Magnesium also occurs as

Magnesium is prepared by the electrolysis of fused anhydrous magnesium chloride.


		2 MgCl2    ==>    2 Mg    +    2 Cl2

Magnesium is also prepared by heating magnesium oxide with carbon above 1000 degC.


		MgO    +    C    ==>    Mg    +    CO

Magnesium is

a bright white metal, which oxidises slowly in air,
burns rapidly in air with a brilliant white flame, and was widely used in photographic flash powders and flash bulbs before the advent of the electronic flash,
```
		2 Mg    +    O2   ==>    2 MgO 
```
may be drawn into a wire and rolled into a ribbon,
is an good conductor of heat and electricity,
burns in steam at 1000 degC to form magnesium oxide and hydrogen,
```
	   Mg   +   H2O    ==>    MgO   +   H2	
```
reacts with dilute acids, with the liberation of hydrogen,
```
	
	   Mg   +   H2SO4   ==>   MgSO4   +   H2	
```
dissolves in a solution of ammonium chloride liberating hydrogen,
```
	Mg  +  NH4Cl  ==>  MgCl2.2NH4Cl   +  NH3  +  H2
```
dissolves in ethereal solutions of methyl iodide (or similar alkyl halides) to form Grignard Reagents which are widely used in synthetic organic chemistry.
```
		   Mg   +   CH3I   ==> CH3MgI 
```

Magnesium is used

as a component in light alloys in the aircraft industry, because of its low density and many of these alloys are resistant to corrosion,
in the nuclear industry in "Magnox" alloys as it is transparent to thermal neutrons,
in the manufacture of Grignard Reagents in organic chemistry, and
in medicine, where magnesium oxide and magnesium carbonate are used as antacids.

Magnesium is detected and quantified by precipitating it as the insoluble magnesium ammonium phosphate.