|Name: silicon||Group number: 14|
|Symbol: Si||Group name: (none)|
|Atomic number: 14||Period number: 3|
|Atomic weight: 28.0855 (3) r||Block: p-block|
|CAS Registry ID: 7440-21-3||Voice: |
|Standard state: solid at 298 K||Colour: dark grey with a bluish tinge|
|Classification: Semi-metallic||Availability: |
Nearing Zero cartoon included by kind permission of Nick Kim.
IsolationHere is a brief summary of the isolation of silicon.
There is normally no need to make silicon in the laboratory as it is readily available commercially. Silicon is readily available through the treatment of silica, SiO2, with pure graphite (as coke) in an electric furnace.
SiO2 + 2C Si + 2CO
Under these conditions, silicon carbide, SiC, can form. However, provided the amount of SiO2 is kept high, silicon carbide may be eliminated.
2SiC + SiO2 3Si + 2CO
Very pure silicon can be made by the reaction of SiCl4 with hydrogen, followed by zone refining of the resultant silicon.
SiCl4 + 2H2 Si + 4HCl