Silicon Dioxide Presentation

1. Silicon Dioxide (Silica)
By Joe Poon, Simon Cheuk and Austin
Zhang(BETRAYED)

2. What structure is SiO2?
SiO2 has a giant covalent sturcture because it contains many Si and O atoms. The atoms
are joined to each other in a regular arrangement, forming a giant covalent structure, which
is tetrahedral due to silicon forming a bond with 4 oxygen atoms when in the giant
covalent for.
Clarification:
● SiO2 technically follows a linear structure in molecular form
● However this is often omitted as it is almost never found this way

3. Physical properties:
- Pure Silicon dioxide is transparent to grey, crystalline, odourless, or an amorphous
solid. They have melting and boiling points as 1713º C and 2950º C, respectively.
The density is about 2.648 g/cm3. It is insoluble in both acid and water and soluble
in hydrofluoric acid. Its molecular weight is about 60.08 g/mol.
Physical Properties

4. Chemical Properties
Chemical properties:
- Silicon dioxide is not a very reactive compound because the polarity of the molecule
is zero. The ‘Si’ forms two double bonds with the oxygen. Therefore, it’s a very
stable molecule. Moreover, it has high dielectric strength, so that it is used as an
insulator and semiconductor.
- Undergoes reduction reaction with Carbon to form Silicon and Carbon Monoxide,
among other various reactions it can undergo.

5. What is Silicon Dioxide used for?
● There is various Silicon dioxide used in electronic, chemical, and pharmaceutical
industries. In the chemical industry, it is used in the production of adhesives and
sealants, adsorbents, ceramic, porcelain, corrosion inhibitors, anti-adhesives, dyes,
and paint additives. In addition, silicon dioxide production occurs in agricultural
chemicals. Coming to pharmaceutical industries, it helps as an additive of food and
medicines to absorb water. For telecommunication, SiO2 is the main component of
optical fibres. Silicon dioxide is extensively used as a precursor to obtaining glass
and silicon by the reaction given below.

6. More usage for Silicon Dioxide
● Used to reinforce concrete as an additive, though excessive amounts can cause slow setting of
concrete
● Used in the production of glass as glass is in a sense a form of quartz, which is a form of
Silica.
● Used as a Sedative
● Turned Silicon in elemental form through reduction reaction for uses in things like
semiconductors
● Used as an anti-caking agent in powdered foods like spices.
● Used as a fining agent in juice, beer, and wine.
● Used pharmaceuticals for making tablets.
● Used in toothpaste to remove tooth plaque
○ Often in powdered form for many of these contexts

7. Reference
All from textbook