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Silicon tetrachloride - Preparation, Properties, Uses | Study Material, Lecturing Notes, Assignment, Reference, Wiki description explanation, brief detail |

Chapter: 12th Chemistry : p-Block Elements-I

Silicon tetrachloride

Silicon tetrachloride is a colourless fuming liquid and it freezes at -70 ⁰C.

Silicon tetrachloride:


Preparation:

Silicon tetrachloride can be prepared by passing dry chlorine over an intimate mixture of silica and carbon by heating to 1675 K in a porcelain tube

SiO2 + 2C + 2Cl2 → SiCl4 + 2CO

On commercial scale, reaction of silicon with hydrogen chloride gas occurs above 600 K

Si + 4HCl  → SiCl4 + 2H2


Properties:

Silicon tetrachloride is a colourless fuming liquid and it freezes at -70 C

In moist air, silicon tetrachloride is hydrolysed with water to give silica and hydrochloric acid.

SiCl4 + 4H2O  → 4HCl + Si(OH)4

When silicon tetrachloride is hydrolysed with moist ether, linear perchloro siloxanes are formed [Cl-(Si Cl2O)nSiCl3 where n=1-6.

Alcoholysis

The chloride ion in silicon tetrachloride can be substituted by nucleophile such as OH, OR, etc.. using suitable reagents. For example, it forms silicic esters with alcohols.

SiCl4 + C2H5OH → 4HCl + Si(OC2H5)4 Tetraethoxy silane


Ammonialysis.

Similarly silicon tetrachloride undergoes ammonialysis to form chlorosilazanes.



Uses:

·           Silicon tetrachloride is used in the production of semiconducting silicon.

·           It is used as a starting material in the synthesis of silica gel, silicic esters, a binder for ceramic materials.

 

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Study Material, Lecturing Notes, Assignment, Reference, Wiki description explanation, brief detail


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