Graphite,Fullerene And Carbon Nanotubules

A short presentation on Graphite,Fullerene And Carbon Nanotubules. Its consists of structures, preparation and properties. Hope you'll like it.

2. CARBON
Crystalline Amorphous
Diamond
Graphite
Fullerene
Coal
Charcoal
Lampblack
Allotropic forms of carbonAllotropic forms of carbon

4. Electronic configuration of CarbonElectronic configuration of Carbon
•C
6
=
1s
2
2s
2
2px
1
2py
1
2p
z
0



C
•*C
6
=
1s
2
2s
1
2px
1
2py
1
2p
z
1
1s 2s
2p
C atoms in
graphite are sp
2
hybridized

5. Sp
2
Carbon
sp
2
carbon has three
hybrid orbitals at 120
o
angle in one plane
(forming sigma bonds
with three such
carbons) and a
hybridized orbital at
right angles to the
plane.

6. Now each of these sp
2
hybridized carbons
combine with each other to form a sheet of
hexagonal arranged network.

7. Each C atom contains
an unhybridized p
orbital. Together due to
resonance they form
rings of delocalized
electrons.

8. •Sheets of graphite are held together by
weak van der waals forces of attraction to
form many layers.
•Two sheets are separated by a distance
of 3.4 Å.
•It is because of this that graphite
molecules can slide over each other on
application of force and graphite is a
smooth material.

9. 1.42 A
o
3.4 A
o

10. The delocalised electrons in the unhybridized p orbital
are free to move anywhere within the sheet - each
electron is no longer fixed to a particular carbon atom.
Because of these free electrons graphite is a good
conductor of electricity.
There is, however, no direct contact between the
delocalised electrons in one sheet and those in the
neighbouring sheets.
Layer of C-
atoms Delocalized
electrons

11. Properties of graphiteProperties of graphite
• It has a high melting point
•It has a soft, slippery feel, and is used in pencils and as a
dry lubricant for things like locks. You can think of
graphite rather like a pack of cards - each card is strong,
but the cards will slide over each other, or even fall off the
pack altogether. When you use a pencil, sheets are
rubbed off and stick to the paper.
•It is insoluble in water and organic solvents
•conducts electricity. The delocalised electrons are free to
move throughout the sheets. If a piece of graphite is
connected into a circuit, electrons can fall off one end of
the sheet and be replaced with new ones at the other end.

12. CARBON
Crystalline Amorphous
Diamond
Graphite
Fullerene
Coal
Charcoal
Lampblack
Allotropic forms of carbonAllotropic forms of carbon

14. DiscoveryDiscovery
•The 1996 Nobel Prize for Chemistry has been
won by Harold W. Kroto, Robert F. Curl and
Richard E. Smalley for their discovery in 1985 of
a new allotrope of carbon, in which the atoms
are arranged in closed shells.
• It was discovered during the experiment of laser
vaporization of graphite rod, under high vacuum
chamber.
•This is because the graphite sheets break down
to form spherical fullerenes.

15. StructureStructure
•Fullerenes are a
cage like structure
having formula
C
60
,C
70
,C
78
.
•All carbon atoms
in C60 are on the
surface hence
they are called
‘bucky balls ’

16. StructureStructure
•The structure of C
60

resembles a soccer ball
of the type made of 20
hexagons and 12
pentagons, with a carbon
atom at the vertices of
each polygon and a bond
along each polygon edge.
•Only restriction is that no
2 pentagons touch each
other.

17. •Diameter is 0.7 nm.
•30 (C=C) double bonds
•FCC structure
•Semiconductor
•Pentagon sites in C
60

are more strained than
hexagonal sites
therefore at high temp.
molecules break at
pentagonal sites
A soccer ball is a model of the
Buckminsterfullerene C
60

18. 70-fullerene graph 60-fullerene graph

19. PropertiesProperties
•It has 60 vertices, 32 faces and a large number of
symmetries.
•C
60
is mustard colour and looks brown and black as
its thickness increases.
•C=C bond length 1.38Ǻ
•C-C bond length 1.45Ǻ
•C
60 has a tendency of avoiding having double
bonds within the pentagonal rings which makes
electron delocalization poor, and results in the
fact that C
60 is not aromatic.

20. PropertiesProperties
•Due to absence of aromatic character fullerenes
behave like alkenes thus undergoing
electrophilic addition.
•Physically bucky balls are extremely strong
molecules being able to resist high pressures.
They will bounce back to their original shape
after being subjected to over 3000 atmospheres.
•Fullerene crystals are bonded weakly with each
other by van der waals forces.

21. ApplicationsApplications
•Forms a superconductor with alkali metals
•Takes part in catalytic processes
•Used as a therapeutic & diagnostic agent
due to size, stability and hydrophobic
nature
•Acts as a potential inhibitor to HIV
•For trapping smaller size ions from
solution of water

22. Singled Walled Carbon
Nanotube (SWCNT)
•Cylinders made of
graphite sheets, closed at
the end with
hemispherical fullerene or
just by a graphite sheet
cap.
•Formed by rolling a
graphite sheet.
•Due to rolling some lattice
strain is developed due to
curvature in the carbon
hexagons.

23. Types of CNT
•There are three types:
1. Zigzag
2. Armchair
3. Helical
•Helical structure
shows a twisted
looking structure.
Achiral
Chiral

25. Synthesis Of Carbon Nanotube
•Electric Arc Discharge
•Chemical Vapour
Deposition
•Laser Ablation (or
Vapourization)

26. Electric Arc Discharge
•Electric arc is struck between
two graphite electrodes
•Electrodes:Graphite diameter
of electrodes- 5 to 25 mm.
•Gap between electrodes: ~1
mm
•Current: 50 to 100 amps
•Voltage: 15 to 25 volts
•Gas pressure: He 100 to 500
torr
• When an electric arc is struck
the temp reaches about 3000°C
and anode evaporates and the
CNT formed is deposited on
cathode.The CNT are aligned in
the direction of current between
the electrodes. Adjustments of
electrode gap without breaking
the vacuum is essential, as the
anode evaporates the gap
increases

27. Chemical Vapour Deposition

28. Laser Ablation