Carbon allotropes

Allotropes of carbon

Carbon is capable of forming many allotropes due to its valency. Well known forms of carbon include diamond and graphite. In recent decades many more allotropes and forms of carbon have been discovered and researched including ball shapes such as buckminsterfullerene and sheets such as graphene. Larger scale structures of carbon include nanotubes, nanobuds and nanoribbons. Other unusual forms of carbon exist at very high temperature or extreme pressures.

1. PRESENTED BY- VINITHA V
ALLOTROPES OF
CARBON

2. KERALA UNIVERSITY COLLEGE OF
TEACHER EDUCATION,KOLLAM

3. ALLOTROPE DEFINITION
•Allotropy or allotropism is the
property of some chemical elements
to exist in two or more different
forms, known as allotropes of these
elements. Allotropes are different
structural modifications of an
element.

4. ALLOTROPES OF CARBON
•Diamond
•Graphite
•“Bucky balls” or
buckminsterfullerene
•Carbon nanotube

5. ALLOTROPES OF CARBON

6. DIAMOND
•Diamond word means “unbreakable“ in
Greek, is a metastable allotrope of carbon,
where the carbon atoms are arranged in a
variation of the face-centered cubic crystal
structure called a diamond lattice.

7. DIAMOND
•Each carbon atom is bonded to 4 others to form a
giant covalent network or lattice
•Is bond is of the same length and equally strong
so the carbon atoms are sp
3
hybridized
•As all the electrons are localised (fixed in
position), diamond is exceptionally hard and it
does not conduct electricity

8. DIAMOND
Each carbon atom is bonded to 4 others to
form a giant covalent network or lattice

9. PROPERTIES OF DIAMOND
•Very high melting point
•Doesn’t conduct electricity
•Good conductor of heat.
•Very hard.
•Fluorescence under UV light and X-ray.

10. GRAPHITE
Graphite, meaning "writing stone“ in
Greek is a semi metal, native element
mineral. Graphite is the most stable form
of carbon under standard conditions.

11. GRAPHITE
•Each carbon atom is bonded to 3 other carbon
atoms to give layers of hexagonal rings
•As each bond is the same, the carbon atoms are
sp
2
hybridised
•The remaining p orbital electron is delocalised to
form weak bonds between the layers
•The covalent layer lattice has all sigma bonds

12. GRAPHITE
Each carbon atom is bonded to 3 other
carbon atoms to give layers of hexagonal rings

13. PROPERTIES OF GRAPHITE
•Because of the layers, graphite is an excellent
lubricant as the layers can slide over each other
•Graphite is also a good conductor of electricity
because of the delocalised electrons e.g. carbon
rods, lead pencils

14. BUCKMINSTERFULLERENE
•Is one member of a family of spherical carbon molecules
sometimes called “buckyballs”
•Has the formula C
60
•The C atoms are arranged in hexagons and pentagons to
give a geodesic spherical structure similar to a football

15. BUCKMINSTERFULLERENE
•Like in graphite, each carbon atom is
bonded to 3 others

16. BUCKMINSTERFULLERENE
•Like in graphite, each carbon atom is
bonded to 3 others
•Each carbon atom is sp
2
hybridized
•There are also delocalized electrons, hence
C
60
can conduct electricity slightly

17. CARBON NANOTUBE
•Carbon nanotubes (CNTs) are allotropes of carbon with
a cylindrical nanostructure.

18. CARBON NANOTUBE
•They have a hollow structure with the walls
formed by one-atom-thick sheets of carbon,
called graphene.
•The chemical bonding of nanotubes is composed
entirely of sp
2
bonds, similar to those of graphite.
•Carbon nanotubes are the strongest and stiffest
materials yet discovered in terms of tensile
strength and elastic modulus.