This presentation is prepared in view of engineering chemistry syllabus. It is useful for Engineering, Sciences and their research to understand basics of chemistry.

1. Chemistry of Carbon
 Carbon is the 4th most abundant
element in universe by mass after H,
He, and O.
 It is 15th most abundant element in the
earth’s crust.

2. Isotopes of Carbon
 C12 : It is stable isotope and it is used as the
standard for measurement of atomic masses of
all other nuclides.
 C13 : It is also stable isotope and used in the
metabolic process by mass spectroscopy.
 It is used in identification of carbon in NMR
spectroscopy.
 C14 : It is radioactive isotope of carbon.
6C14 -β
7N14
C14 required for research is made by neutron
irradiation on N14
7N14 + 0n1
6C14 + 1H1
It is used as carbon dating.

3. Allotropes of Carbon
 Carbon is stabilized by forming
different multiatomic structures having
different molecular configuration called
allotropes of carbon.
1. Crystalline: Diamond, Graphite
2. Carbon clusters: Fullerene, Carbon
nanotube, Graphene
3. Amorphous: Carbon black,
Activated carbon, carbon fibres

4. Diamond
 Occurrence
 Diamonds occurs in the form of
rounded pebbles in South Africa,
Brazil, Australia & India
Large Diamond cut as gemstones
 80% of mined diamonds has less
clarity, colour , etc. & are used for
industrial purpose for cutting, polishing
etc.

5. Diamond
 Structure

6. Diamond
 Synthetic Diamond
1. High pressure, High temperature
method:
 Synthesized by using graphite &
transition metal like Ni heated to
1500 – 2000K & at 7 Gpa pressure
 Synthesized by using graphite
without metal catalyst if the
temperature & pressure are high
enough.

7. Diamond
2. Chemical vapour deposition
method
The method involves feeding a
mixture of gases (1:99, methane &
hydrogen) into a chamber & splitting
them to chemically active radicals in
plasma ignited by arc discharge,
laser or hot filament & under a low
pressure.

8. Diamond
Properties
 It is crystalline three dimensional
structure
 Large numbers of carbon arranged in
tetrahedral manner (sp3
hybridization)
 C-C bond length is 1.54A0
 Due to high strength of covalent
bonds, it is very hard & has high
density.

9. Diamond
Application
 Because of its durability, clarity & high
refractive index diamond is used as
highly priced gemstone
 It has highest known thermal
conductivity, because its structure
distributed thermal motion in 3
dimensions very effectively
Diamond can be used for industrial
purposed in cutting , drilling, grinding,
polishing tools because of high
hardness.

10. Graphite
 Occurrence
 Occurs in China, India, Brazil, North
Korea, Canada.
 Usually found as a mixture with mica,
quartz & silicates.
 Graphite is evaporated from most of the
impurities by floatation.
 It is purified by heating with HCl & HF in
vacuum to remove trace of silicon
compound of SiF4
It is occur in metamorphic rock.

11. Graphite
 Structure
 Crystalline allotropes of carbon.
 each carbon atom is Sp2 hybridized
 It produced hexagonal rings connected together to
form two dimensional large plane sheet with network
of single & double bond.
 The sheet are held together by weak Vander waal’s
forces.
 C – C bond length is 1.42A0
 The distance between two successive layers is 3.36
A0

13. Graphite
 It is a good conductor of electricity –
the 4th valency of each carbon
remains unsatisfied (remains unpaired
or free) . This free electron can easily
move from one carbon to another
under the influence of potential.
Conductivity can occur in sheet but
not from one sheet to another.

14. Graphite
 Synthetic Graphite ( By Acheson
process)
 A mixture of sand & powder anthracite is heated strongly in
an electric furnace consist of two carbon electrodes
connected by thin carbon rod. An alternating current is
passed & heating is continued for 24 – 30 hr. Silicon carbide
first formed decomposed into graphite & silicon. Silicon
volatilizes off leaving behind graphite.
SiCCOCSiO  22
2
CSiSiC 

15. Graphite
 Application
 As a solid lubricant
 As a electrode in all major batteries
 It is used as refractory material.
Graphite crucible are used to hold
molten metal.
 used in making lead pencils

16. Graphite Intercalation Compound
 Intercalation means the insertion of
layers of atoms, ions or molecules of
chemical species between the layers of
host material to form sandwich type of
compounds.
 Graphite intercalation compound have
conductivity.
 When the graphite & guest
atom/molecules interact by charge
transfer, the interplanar electrical
conductivity increases.
Graphite can act as electron donor or
acceptor.

17. Graphite Intercalation Compound
 e.g. Potassium graphite –
K atom reduce graphite by
donating their valence
electron to the empty
orbitals of π * band of
graphite (K K+ + e- )
 Resulting K+ ions
penetrate between
graphite layers.
 Electron added in the
band are mobile &
therefore show high
conductivity.

18. Graphite Intercalation Compound
 E.g. Graphite bisulfates –
 Graphite bisulfates is formed by heating
graphite with a mixture of sulfuric & nitric
acids.
 In this reaction, electrons are removed
from the π – band & HSO4
- ions
penetrate between the sheets to give
(C24)+HSO4
-
In this oxidation intercalation reaction,
the removal of electrons from the full π –
band lead to higher conductivity than
graphite.

19. Comparison of Diamond and
Graphite Diamond
 Each carbon is sp3
hybridized.
 Each carbon is covalently
bonded with four carbons.
 The density is 3.51 gm/cc.
 Bad conductor of electricity
but good conductor of heat.
 3-D arranged carbon atoms.
 Hardest substance, useful
cutting & drilling.
 Thermodynamically lesser
stable.
 Chemically non-reactive,
transparent colorless.
 Graphite
 Each carbon is sp2
hybridized.
 Each carbon is covalently
bonded with three carbons.
 The density is 2.22 gm/cc.
 Good conductor of electricity.
 2-D arranged carbon atoms.
 Soft, used as lubricant and
for electrodes.
 Thermodynamically more
stable.
 Chemically more reactive
and black colored.

20. Graphene
 Single layer of graphite is
called graphene
 It structure is one atom thick
planer sheets of sp2 bonded
carbon atoms that packed
closely in honeycomb crystal
lattice
 It can be wrapped into zero
dimension fullerene, rolled into
two dimensional carbon
nanotube.
 C – C bond length is 0.142 nm
 It has extraordinary electrical,
thermal & physical properties.
 It is thinnest, strongest

21. Graphene
 Preparation
 Tiny fragments of graphene sheets
are produced whenever graphite is
abraded.
 Sodium metal is slowly heated with
ethanol for 3 days & than heated
rapidly. The resulting solid consist of
fused graphene sheet which are then
washed dried to separate them but the
quality of the sheet is not good.

22. Graphene
 Application
 As sensor for gas detection.
 In transistors as a component of
integrated circuits.
 In making transparent conducting
electrode.
 In gas storage
 In solar cell

23. Fullerenes
 Fullerenes are carbon clusters allotropes.
 They consist of hollow spherical cluster of large
number of carbon atom.
 The most common fullerences is C60 molecules,
known as Buckminister fullerence.

24. Fullerenes Structure
 zero dimensional allotrope of
carbon
 carbon atoms arranged in a series
of pentagon & hexagon rings to
form structure of football. The
diameter of ball is 0.7 nm
 60 C atoms are sp2 hybridized.
There are 30 double bond in C60.
C – C bond length is 1.45 A0 & C =
C bond length is 1.38 A0.
 The π electrons of double bonds
are delocalized.
 Show reaction such as
electrophilic addition
reaction,Diel;s-alder reaction,

25. Fullerenes – Preparation
 Fullerenes are synthesized using electric arc
discharge between carbon electrodes in an inert
atmosphere.
 The heat generated at the contact point between
the electrode, evaporates carbon to form soot &
fullerenes
 Which are condense on the water cooled walls of
the reactor.
 These are extracted in toluene or benzene.
 Solution contain C60,C70, C76, C82, etc.
 They are separated from each other by
chromatography.

26. Fullerenes - Application
1) Electrical conductivity is low. It is
increased by doping with alkali
metals. than it is used as a
superconductor.
2) It is tough & has impact resistance.
So it is used as a lubricant.
3) C60 incorporated with alkali metal
can act as catalyst for chemical
reaction.
4) C60 molecules can bind large
number of hydrogen atoms. So it can

27. Carbon Nanotubes (CNT)
 CNTs can be imagined as cylinders
formed by graphene sheet ( single
sheet of graphene & capping by
hemisphere structure similar to
fullerene hemisphere ( half of fullerene
including pantagon & hexagon)
 Types of Nanotubes
1) Single walled Nanotubes (SWNT)
2) Multi-walled Nanotubes (MWNT)

28. Carbon Nanotubes (CNT)
1) Single walled Nanotubes (SWNT)
 Structure - of SWNT can be wrapping a single
atom thick layer of graphene in to a cylinder.
 Three types of SWNT- zigzag, armchair & chiral
can be imagined by three different ways of
wrapping graphene sheet.
 Bonding in carbon nanotubes is SP2
 Armchair SWNT show metallic conductivity
 Other two are semiconductor
 CNTs are stiffer than steel. They have high
tensile strength & high resistance to damage from
physical force.

30. Carbon Nanotubes (CNT)
2. Multi-walled Nanotubes (MWNT)
It is multiple rolled layers or concentric tubes
of graphene. The length, diameter & hence
porperties of MWNT differ from SWNT

31. Carbon Nanotubes (CNT) –
Preparation methods
1) Pyrolysis of hydrocarbon-
Acetylene 7000C CNT
Fe-graphite/ CO-graphite
/ Fe-Silica
2) Arc vaporization of graphite – prepared by striking a direct current
arc between the graphite electrode separated by about 1 mm in
inert atmosphere gives MWNT & in presences of metal catalyst
like iron , cobalt, nickel in helium atmosphere SWNT

32. Carbon Nanotubes (CNT) –
Preparation methods
3. Evapouration – a pulsed laser vapourise a
graphite & small amount of CO & Ni in high
temperature ( 12000C) quartz tube reactor in
inert atmosphere. The method gives high
amount of SWNT.
4. Chemical Vapour Deposition (CVD) – It
involved decomposing a hydrocarbon gas
such as methan, acetylene, ethylene etc. at
high temp. of about 11000C in the presence
of metal catalyst (Ni, Co, Fe supported on
mgO or Al2O3) Carbon atoms are produced
after decomposition of hydrocarbon which
condense on a cooler surface containing
metal catalyst to form CNT.

33. Carbon Nanotubes (CNT) –
Application
 Hydrogen storage material – in fuel cell as CNT
can hold 7.7% hydrogen by weight by physical
adsorption.
 Batteries – used in lithium vatteries.
 Sensors – On exposure to environment, which
contain NO2,NH3 or O2 the electric resistance
changes.
 Composite material – Because of high stiffness,
CNT can be used as reinforcement in high
strangth,low weight composite.
 drug delivery vessel – used for drug delivery
within the body by placing the drug within the
tube or by attaching the drug to the side of the
tube.

34. Amorphous / Partially Crystalline
Carbon
 Amorphous carbon do not have long
range orderly arrangement but
possess only some short range order
of atomic position.
 Partially crystalline materials of
carbon have considerable commercial
importance.
 e.g. carbon black, activated
carbon,carbon fibres

35. Carbon black/ soot
Preparation
It is prepared by combustion of
hydrocarbon under oxygen deficient
conditions.
Structure
planar stacks like graphite &
multilayer balls, reminiscent of
fullerene

36. Carbon black/ soot
Application
 used as a black pigment. It is used in
printer’s ink.
 used as a filler for rubber goods,
including tyres.

37. Activated carbon/ Activated
Charcoal
Preparation
By pyrolysis of organic material, including
coconut shell.
Structure
Has high surface area due to small particle
size.
Part of the surface defined by the edges of
hexagonal sheet are covered with oxidation
product including carbonyl & hydroxyl group.
(surface activity)
It is efficient adsorbent for molecules
including organic polluntants from drinking
water, nontoxic gases from air & impurities
from reaction mixture.

38. Activated carbon/ Activated
Charcoal
Application
 used as an excellent adsorbent in gas
masks to adsorb poisonous gases.
 used for removing offensive odour from
air used in air conditioning process.
 used in decolourising sugar syrup as
well as for refining of oils,fats
glycerine,etc.
Used in treatment of drinking water after
chlorination, to adsorb the excess of
chlorine
Used as a catalyst for some reaction.

40. Carbon Fibres
 preparation
It is made by controlled pyrolysis ( temp. 15000C
or above) of asphalt fibres or synthetic
fibres(polymer fibre like polyacrylonitrite,
cellulose)
 Structure
is that of graphite but instat of extended sheet,
the layers consist of ribbon. Strong planar bonds
give fibres a high tensile strength
 Application
The fibres are incorporated into variety of
polymers to give high strength, light weight
plastics products such tennis rackets, aircraft
components etc.