The document discusses the structures and classifications of silicates, including orthosilicates, pyrosilicates, ring silicates, chain silicates, sheet silicates, and framework silicates, highlighting examples such as topaz and quartz. It also covers the properties and applications of silicon and silicone materials in various industries, including semiconductors, ceramics, and glassmaking, as well as the use of zeolites as molecular sieves and ion exchangers. Additionally, it mentions the applications of tin and lead in electroplating and manufacturing of alloys.

1. Silicon , Silicone and Silicates.
LEARNING OUTCOME
• Should able to describe the structure of
silicone and silicates (pyroxenes and
amphiboles) , sheets (mica) and framework
structure (quartz)

2. SILICATES
• Silicon forms a strong bond with oxygen.
• Silicon forms a class compound with oxygen called silicates.
SILICON + OXYGEN SILICATES
(CLASS COMPOUND)
• The basic unit in all silicates is the tetrahedral ion ,[SiO4]4− .

3. • The classification of silicates depends on how the tetrahedral units
are arranged.
Main
classes of
silicates
Orthosilicates
Pyrosilicates
Ring silicates
Chain
silicates
Sheet
silicates
Framework
silicates

4. ORTHOSILICATES
• The mineral that contains individual tetrahedral units are called
orthosilicates or nesosilicates .
• This Orthosilicates have high densities and high refractive index .
Thus , they are used as gemstones.
• Examples of Gemstones included Topaz , Phenacite and Zircon
• Topaz is Aluminium Silicate Flouride Hydroxide .
• The structure of Topaz is controlled by a chain like structure of connected
octahedrons. These octahedrons have an aluminum in the middle surrounded
by four oxygen. Above and below the aluminum are the hydroxide or fluoride
ions. The chains of octahedrons are held together by individual silicate
tetrahedrons but it is the octahedron chains that give topaz its crystalline
shape.

10. PYROSILICATES
• When two tetrahedral units are joined by sharing one oxygen
atom per tetrahedron
• So then pyrosilicates are formed.
• Known as Sorosilicates.
• Examples of pyrosilicates are thortveitite and hemimorphite.

11. RING SILICATES
• This is formed when each tetrahedral unit shares two oxygen
atoms.
• The most common ring silicates are composed of minimum three
tetrahedral forming triangular rings as in the mineral Benitoite.
• Some of these minerals are also used as gemstones.

12. RING SILICATES
With four
Tetrahedra is
Axinite
With six
Tetrahedra is
Tourmaline

13. CHAIN SILICATES
Single Chain Silicate (Pyroxene)
• Two oxygen atoms per unit
tetrahedron are shared to form a
single chain. The mineral pyroxene
is formed.
• The tetrahedra are arranged in
alternate positions to the left and
the right along the chain. However,
more complex chains may be spiral.
• Examples : Jadeite and Diopside
Double-chain Silicate (Amphibole)
• Two Pyroxene chains are joined by
sharing another oxygen atom to form a
double chain , Amphibole is formed.
• Some tetrahedra share two oxygen
atoms while others share three.
• The most common amphibole : Asbestos
• Asbestos is strong and hard but brittle. It
is cheap and resistant to heat, acids and
alkalis . However , asbestos dust can
cause lung cancer.

14. SHEET or LAYER SILICATES
• When each tetrahedral unit shares three oxygen atoms, a two-
dimensional infinite sheet silicate will be formed.
• Weak van der Waals forces hold the silicate sheets together. The
sheets can therefore slide over one another rather easily , making
sheet silicates soft and slippery.
• Examples : Mica , talc , kaolinite and etc

15. FRAMEWORK SILICATES
• All four oxygen atoms per unit tetrahedron are shared , a three-
dimensional structure of SiO2 will be formed.
• Example of 3-D framework : quartz , trdymite and crystobalite.

17. SILICONE
• Silicone is a synthetic organosilicon polymer
containing Si-O-Si bonds.
• A typical silicone polymer can be
represented as follows, R represents an alkyl
group , eg : Methy, -CH3

18. • Some common forms include
- Silicone fluid
- Silicone elastomer
- Silicone resin
• Silicone resins usually contain cross-linked
silicone polymers.

19. PROPERTIES &
USES
Used to make
sealants for glass,
ceramics and
metals due to the
strong Si-O which
resistant to
chemical
corrosion.
Silicone Fluids are
used extensively as
lubricants in high-
temperature
equipment due to
its stability
towards heat and
light.
Silicone Elastomer
used to make
surgical implant .
Why ? Coz its not
toxic.
Silicone resins
used as an
insulator for wire
casings & pot
holders.
Silicone Fluid used
to make Car polish
and other water-
proof materials .
Coz, it’s a good
water repellant
due to its alkyl
group .

20. USES OF SILICON
• Silicon is a metalloid
• It is used widely as semiconductors for
intergrated circuits in microchips ,
transistors an solar batteries.
• The conductivity of silicon can be replaced
by increasing its temperature and by
doping with phosphorous and boron.

21. USES OF SILICATES
• Always depends on their physical properties.
• QUARTZ – to make electronic equipment, watches ,
gems and lenses.
• MICA – to make electrical insulator in high voltage
electrical equipment and in capacity.
• ASBESTOS – is a heat insulator. To make fire retardant
coating, ceiling sheets, vehicle brake linings, exhaust
manifolds and gaskets.
• Used widely in ceramics , cement and glass.

22. CEMENTS
• Is made by heating a mixture of limestone which is
calcium carbonate , silicate clay and sand to a high
temperature.
• Mostly widely used in construction industry.

23. GLASS
• When silicon(IV) oxide is heated to its melting point ,
the Si-O bonds break and it melts to form a viscous
liquid. When cooled rapidly, silicate glass is formed.
• The silicon and oxygen atoms in glass are not arranged
in a regular manner . This makes the glass an
AMORPHOUS SOLID.
• Glass is soluble in hot obviously , concentrated alkalis as
it contains silicon dioxide which is acidic.
SiO2 (s) + 2NaOH (aq)  Na2SiO3 (aq) + H2O (l)
• Hence, hot and concentrated alkalis should not be stored
in glass containers.

24. Properties of
Glass (can be
modified by
adding oxides of
other elements)
Transparent
Inert towards
many
chemicals
HardBrittle
Non-porous

25. CERAMICS
• The aluminium ion can easily substitute for the silicon ion to form
aluminosilicates. However, the charge on an aluminium ion is +3 while that on
a silicon ion is +4 . To balance the charge, other cations are incorporated in the
structure.
• Ceramics are one of the examples of ALUMINOSILICATES.
• Advanced ceramics incorporate carbides, oxides and nitrides in their structure.
Some examples include silicon carbide , aluminium oxide and silicon nitride.
Some of the advanced ionic ceramics can be made into superconductors when
cooled by liquid nitrogen.

26. PROPERTIES USES EXAMPLES
Hard and strong Building materials Bricks, Tiles ,
Cement
Attractive in
appearance
Decorative Items Porcelain plates
and vases.
Electrical
insulators
Make insulating
parts in electrical
equipment
Insulators in
toasters and iron ,
spark plugs.
Chemically inert
and non-
corrosive
Household
materials
Plates, bowls ,
cooking utensils.
Heat resistant Heat insulating
layers
Refractory lining
of furnace and
outer body of
space shuttles.

27. ZEOLITES
• Some aluminosilicates lose water when heated to forms a porous
structure with a large surface area.
• These aluminosilicates are called ZEOLITES.

28. USESOFZEOLITES AS MOLECULAR SIEVES
- Used as molecular sieves where they can retain molecules that can fit into their
molecular cavities.
- Is to separate straight-chain hydrocarbons from branched-chain hydrocarbons
in gas chromatography.
AS ION EXCHANGERS
- Used in exchange (ions) columns where the ions in zeolites can be exchanged with other ions.
-This process needs Soften Hard Water. When hard water containing Ca2+ and Mg2+ ions will
pass through zeolite, then the Ca2+ and Mg2+ ions will be replaced with Na2+ ions
Na2Z + Ca2+ (aq) <--> CaZ + 2Na+
AS CATAYLST
- Have the ability to act as catalyst for chemical reactions
which take place within internal cavities.
- Used in many organic reactions

29. TIN ALLOYS
USES OF TIN
& LEAD
TIN
- Used in
electroplating
industry (Iron
and Steel)
TIN PLATED
IRON
- Used to
make tin cans
for food (Tin
is not toxic)
TIN & LEAD
- Used to
make alloys

30. ALLOYS
SOLDER
• Consist of 70% of Pb and
30% of Sn
• Used as soldering electronic
parts.
PEWTER
• Consists of 96% of Sn , 3%
of Cu and 1% of Sb
• Used as souvenirs ,
décorative items.