Silicon Synthesis (From Mg and Sand) [Full HD]
Merry Christmas, Everyone! As a present from me to you, I have a Christmas-themed video for you guys! Because what says "Merry Christmas" better than a powdered, black, semiconducting metalloid??
In this video, I synthesize silicon (Si). Silicon is a metalloid used in semiconductors and computer chips. It also makes up 28% of the earth's mass, and is found in sand and quartz. It has a wide
range of interesting physical and chemical properties, and in a later video I will be reacting it with chlorine to make silicon tetrachloride (SiCl4).
SiCl4 is an interesting chemical and I will tell you more about its properties in the upcoming video.
Anyway, back to the silicon synthesis. The standard method of synthesizing silicon is a thermite reaction, either with sand (silicon dioxide; SiO2) and aluminum or sand and magnesium. However, I could not perform a thermite reaction for several reasons, mainly the lack of a container to contain the molten silicon resulting from the thermite.
So I decided to use a modified version of Nile Red's Magnesium Silicide Synthesis (link below) to make silicon.
Link to the video: • Making Magnesium Silicide and Explosive Si...
In his synthesis, he heats silicon dioxide and magnesium together, with the magnesium being in excess. Two reactions occur, shown below:
Reaction 1: 2Mg + SiO2 = 2MgO + Si
Reaction 2: Si + 2Mg = Mg2Si
In the first reaction, the magnesium combusts by stripping the oxygen from the SiO2 and forms silicon. The Silicon produced then reacts with the remaining hot magnesium to produce magnesium silicide. It is for this reason that the magnesium is in excess.
Now I figured that by instead making silicon dioxide the excess reagent, we could prevent the second reaction from occurring (or at least make it occur to a lesser extent) and end up with some elemental silicon.
So that's what I did! I reacted magnesium powder with a 20% excess of silicon dioxide (impure; I should have washed it with water and HCl). The product of the reaction, once washed, was a dark black powder, which is a good sign that the reaction actually worked and that we made actual silicon.
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Merry Christmas and a Happy New Year!