Engler and Prantl system of classification in plant taxonomy
Allotropes of Carbon.ppt
1.
2. Allotropes
An allotrope is a different form of the same element
Carbon can bond with itself in different ways giving us
3 different materials
Diamond
Graphite
Buckyballs and nanotubes.
All are allotropes of Carbon.
3. Diamond
Each carbon is bonded
with strong covalent
bonds to 4 other
carbon atoms forming
a giant network
covalent compound.
4. Properties of Diamond
High melting point due to strong directional
covalent bonds (3550 C)
Extremely hard because it is difficult to break
atoms apart or move them in relation to one
another
No electrical conductivity because electrons are
localized in specific bonds
Insoluble in polar and non-polar solvents because
molecular bonds are stronger than any
intermolecular forces
5. Graphite
Each carbon atom is
bonded to 3 other
carbons with strong
covalent bonds.
Carbon atoms form
sheets of six sided rings
with the 4th valence
electron delocalised
between them.
6. Graphite Structure
Carbon has 4 valence
electrons to bond with.
3 are used for covalent
bonds making rings.1 is
delocalized.
van der waals forces
hold the sheets
together.
9. Properties of Graphite
Different from Diamond
Conducts electricity because of delocalized electrons
Slippery can be used as lubricant, sheets can easily slip
past each other (think of a deck of cards)
Same as Diamond
High melting point (higher actually because of
delocalized electrons, 3653C)
Insoluble (same reason)
10. Fullerenes
Buckyballs: spherical
Nanotubes: tube
shaped
Both have very
interesting properties
Super strong
Conduct electricity and
heat with very low
resistance, a
SUPERCONDUCTOR
11. Buckyballs
Carbon atoms bond in units of
e.g.,60 atoms (C60) forming a
structure similar to a football
with interlocking six sided and
five sided rings (note, other
types also exist).
Presence of delocalised
electrons leads to
High electrical conductivity
Stronger bonds so
super strong materials