IB Chemistry on Allotrope of Carbon, Graphene, Alloy and Metallic Bonding

1. Tutorial on Allotropes of Carbon, Metallic
Bonding, properties of graphene and alloys.
Prepared by
Lawrence Kok
http://lawrencekok.blogspot.com

2. Allotropes of Carbon Element exist in different form/physical state
Graphite Graphene
Diamond Fullerene, C60
Bond to 3 C atoms
Bond to 4 C atoms
Bond to 3 C atoms
…

3. Allotropes of Carbon Element exist in different form/physical state
Diamond Fullerene, C60
• Carbon- sp2 hybridization
• Bonded in geodesic shape
• 60 carbon in spherical - 20 hexagon/ 12 pentagon
• 1 π electron free to delocalized.
• Surface is not planar, but sphere
• Electrons NOT able to flow easily.
Graphene
• Carbon- sp2 hybridization
• Carbon bond to 3 others form hexagon (120)
• Exist chicken wire/honeycomb- 1 layer
Bond to 3 C atoms
• Carbon- sp3 hybridization
• Bonded tetrahedrally
• Strong hard covalent network
• Carbon- sp2 hybridization
• Bonded Trigonal planar (layers)
• Giant covalent structure (2D)
• Strong covalent network within layers
• Weak Van Der Waals force bet layers
Giant covalent structure (3D)
Giant covalent structure (2D)
Molecular structure
✓
✓ ✓
Giant covalent structure (2D) ✓
Graphite
Bond to 4 C atoms
Bond to 3 C atoms
…

4. Allotropes of Carbon Element exist in different form/physical state
Graphite
Diamond Fullerene, C60
Bond to 3 C atoms
• Carbon- sp2 hybridization
• Bonded in geodesic shape
• 60 carbon in spherical - 20 hexagon/ 12 pentagon
• 1 π electron free to delocalized.
• Surface is not planar, but sphere
• Electrons NOT able to flow easily.
Graphene
Bond to 3 C atoms
…
• Carbon- sp2 hybridization
• Bonded Trigonal planar (layers)
• Giant covalent structure (2D)
• Strong covalent network within layers
• Weak Van Der Waals force bet layers
Giant covalent structure (2D)
✓ ✓
• Carbon- sp2 hybridization
• Carbon bond to 3 others form hexagon (120)
• Exist chicken wire/honeycomb- 1 layer
Bond to 4 C atoms
• Carbon- sp3 hybridization
• Bonded tetrahedrally
• Strong hard covalent network
Giant covalent structure (3D)
Molecular structure
✓
Giant covalent structure (2D) ✓
Uses of graphene
Click here to view Click here to view Click here to view

5. Allotropes of Carbon Element exist in different form/physical state
Diamond Graphite Graphene Fullerene, C60

6. Allotropes of Carbon Element exist in different form/physical state
Diamond Graphite Graphene Fullerene, C60
Electrical conductivity Electrical conductivity Electrical conductivity Electrical conductivity
✗ Good
✓ Semiconductor
- Within layer, C sp2 hybridized
- ONE free delocalized π electron
Very Good
- Within layer, C sp2 hybridized
- ONE free delocalized π electron
moving across the layer easily
Poor
- C sp3 hybridized
- No free moving electron
- Surface sphere, not planar
- Electrons CANNOT flow easily.
- Lower electron mobility

7. Allotropes of Carbon Element exist in different form/physical state
Diamond Graphite Graphene Fullerene, C60
Electrical conductivity
✗ ✓ Semiconductor
Special property
Electrical conductivity Electrical conductivity Electrical conductivity
Special property
Good
- Within layer, C sp2 hybridized
- ONE free delocalized π electron
Very Good
- Within layer, C sp2 hybridized
- ONE free delocalized π electron
moving across the layer easily
Poor
- C sp3 hybridized
- No free moving electron
- Surface sphere, not planar
- Electrons CANNOT flow easily.
- Lower electron mobility
- Soft, layer slide
across each other
- Hardest substance
- Jewellery
Special property
graphite lubricant electrode
Lightest/strongest material
replacing silicon in photovoltaic cell
Drug delivery Transistor/Electronic
Transparent conducting
electrode
Drug in graphene Click here uses graphene

8. Allotropes of Carbon Element exist in different form/physical state
Graphene
• sp2 hybridization
• Exist as 2D/chicken wire/honeycomb
• Stronger than diamond, x200 stronger steel
• Conductive than copper
• Flexible/Transparent/lighter than rubber
• Solar cell and batteries
Single sheet conductor Rool into conductive nanotubes

9. Allotropes of Carbon Element exist in different form/physical state
Graphene Fullerene, C60
Electron in hexagonal rings do not
delocalized over whole molecule.
6:5 bond bet hexagon and pentagon
6:6 bond shorter than 6:5
60 carbon in spherical
((20 hexagon/12 pentagon)
• sp2 hybridization
• Exist as 2D/chicken wire/honeycomb
• Stronger than diamond, x200 stronger steel
• Conductive than copper
• Flexible/Transparent/lighter than rubber
• Solar cell and batteries
Single sheet conductor Rool into conductive nanotubes
6:6 bond length bet two hexagon
Double bond
Single bond

10. Allotropes of Carbon Element exist in different form/physical state
Graphene Fullerene, C60
Single sheet conductor Rool into conductive nanotubes
Click here to view touch screen
Electron in hexagonal rings do not
delocalized over whole molecule.
6:5 bond bet hexagon and pentagon
6:6 bond length bet two hexagon
6:6 bond shorter than 6:5
Macroscopic properties
60 carbon in spherical
((20 hexagon/12 pentagon)
•High tensile strength
•High electrical /heat conductivity
•High ductility and chemical inactivity
Potential medicinal use
•Trap/bind drug inside/outside cage
•Target cancer cells
Drug inside Drug bind outside
• sp2 hybridization
• Exist as 2D/chicken wire/honeycomb
• Stronger than diamond, x200 stronger steel
• Conductive than copper
• Flexible/Transparent/lighter than rubber
• Solar cell and batteries
Graphene touch screen and photovoltaic cell
Click here for application of graphene
Double bond
Electrical contact
photovoltaic cell
Lightest and strongest replacing silicon in photovoltaic cell
Single bond

11. Uses of Carbon Allotropes
rool into rool into
sp2 hybridization
graphene
• Conduct current/heat very well
• Conduct current at speed of light
• Electron delocalized above/below plane
• High electron mobility
CNT- fullerene family of carbon allotropes.
Hollow cylindrical molecule
Rolling single or multiple layers of graphene sheet.
Single-wall SWNT/ multi-wall MWCNT
High tensile, stable, unreactive
Carbon Nanotube (CNT)
1 layer thick
Single wall Nanotube (SWNT) Multi wall Nanotubes (MWNT)

12. Uses of Carbon Allotropes
rool into rool into
sp2 hybridization
graphene
• Conduct current/heat very well
• Conduct current at speed of light
• Electron delocalized above/below plane
• High electron mobility
CNT- fullerene family of carbon allotropes.
Hollow cylindrical molecule
Rolling single or multiple layers of graphene sheet.
Single-wall SWNT/ multi-wall MWCNT
High tensile, stable, unreactive
Carbon Nanotube (CNT)
1 layer thick
Single wall Nanotube (SWNT) Multi wall Nanotubes (MWNT)
Uses of CNT
Strong tubes as
space elevator
Filter off salt
(desalination)
Drug delivery to body Attachment drug
therapeutics

13. Uses of Carbon Allotropes
rool into rool into
sp2 hybridization
graphene
• Conduct current/heat very well
• Conduct current at speed of light
• Electron delocalized above/below plane
• High electron mobility
CNT- fullerene family of carbon allotropes.
Hollow cylindrical molecule
Rolling single or multiple layers of graphene sheet.
Single-wall SWNT/ multi-wall MWCNT
High tensile, stable, unreactive
Carbon Nanotube (CNT)
Single wall Nanotube (SWNT) Multi wall Nanotubes (MWNT)
Click here discovery graphene Click here TEDtalk graphene
Click here CNT Click here to view
1 layer thick
Uses of CNT
Strong tubes as
space elevator
Filter off salt
(desalination)
Drug delivery to body Attachment drug
therapeutics

14. Metallic Bonding
Metals
Metallic bonding
Electrostatic forces attraction
- bet lattice of positive ions with
delocalized electron
Metallic elements- Cu, Na, K, Cu
Lattice of positive ions with sea of free electrons

15. Metallic Bonding
Metals
Metallic bonding
Electrostatic forces attraction
- bet lattice of positive ions with
delocalized electron
Metallic elements- Cu, Na, K, Cu
Lattice of positive ions with sea of free electrons
Metallic Bonding
Metallic Property
Electrical conductivity Thermal conductivity
Malleability/Ductile High melting point
High Temp Low Temp
heat flow
electron flow
Delocalized free moving electron carry charge/heat
✓
Form sheet by hammering
Ductile -stretch into wires
Bend and shaped
Strong Electrostatic force attraction
- between lattice of positive ions with
Atom able to roll/slide to new position
without breaking metallic bond
delocalized electron

16. Melting Point • Temp when solid turn to liquid (temp remain constant)
• Energy absorb to overcome forces attraction bet molecule
Factors affecting melting point for metals
• Melting point across Period 2/3
• Melting point down Gp 1
Gp 1
Period 2/3
Metallic Bonding
Melting Point metals
Electrostatic forces attraction
- bet lattice of positive ions with
delocalized electron
Electrostatic force attraction
Metallic Bonding

17. Melting Point • Temp when solid turn to liquid (temp remain constant)
• Energy absorb to overcome forces attraction bet molecule
Factors affecting melting point for metals
• Melting point across Period 2/3
• Melting point down Gp 1
Gp 1
Period 2/3
Metallic Bonding
Melting Point metals
Electrostatic force attraction
period 2
period 3
period 2
period 3
Li
Be
B
C
N O F Ne
Na
MgAI
Si
P S CI
Electrostatic forces attraction
- bet lattice of positive ions with
delocalized electron
Melting point across Period 2 and 3
Melting point across
Period 2 and 3
Size of atom decrease ↓ Number delocalized
electron increase ↑
Electrostatic forces attraction
INCREASES ↑
Melting point
INCREASE ↑ ✓
Metallic Bonding
Metalic Bonding
INCREASE ↑

18. Melting Point
Gp 1
Period 2/3
Metallic Bonding
Melting Point metals
Metallic Bonding Electrostatic force attraction
Electrostatic forces attraction
- bet lattice of positive ions with
delocalized electron
• Temp when solid turn to liquid (temp remain constant)
• Energy absorb to overcome forces attraction bet molecule
• Melting point across Period 2/3
• Melting point down Gp 1

19. Melting Point
Gp 1
Period 2/3
Metallic Bonding
Melting Point metals
• Temp when solid turn to liquid (temp remain constant)
• Energy absorb to overcome forces attraction bet molecule
Metallic Bonding Electrostatic force attraction
Electrostatic forces attraction
- bet lattice of positive ions with
delocalized electron
Number delocalized electrons
Factors affecting Metallic Bonding
Charge on cation Radius cation
Higher ↑ charge cation
Higher ↑ metallic bonding
(melting point)
Bigger ↑ radius cation
Lower ↓ metallic bonding
(melting point)
Higher ↑ number delocalized electrons
Higher ↑ metallic bonding
(melting point)
• Melting point across Period 2/3
• Melting point down Gp 1

20. Melting Point
Gp 1
• Melting point across Period 2/3
• Melting point down Gp 1
Period 2/3
Metallic Bonding
Melting Point metals
• Temp when solid turn to liquid (temp remain constant)
• Energy absorb to overcome forces attraction bet molecule
Metallic Bonding Electrostatic force attraction
Electrostatic forces attraction
- bet lattice of positive ions with
delocalized electron
+1 +2
✓
Number delocalized electrons
Factors affecting Metallic Bonding
Charge on cation Radius cation
Higher ↑ charge cation
Higher ↑ metallic bonding
(melting point)
Bigger ↑ radius cation
Lower ↓ metallic bonding
(melting point)
Higher ↑ number delocalized electrons
Why m/p Na (Gp 1) less than Mg (Gp 2) ? Why melting
point different?
ONE delocalized
electron per atom
TWO delocalized
electron per atom
Radius cation Bigger ↑ Radius cation Smaller ↓
MELTING POINT MELTING POINT
Higher ↑ metallic bonding
(melting point)
Charge cation smaller ↓ Charge cation Bigger ↑

21. Metals
•Same type of elements/atom arrangement
•Malleable – shaped by hammering
•Ductile –deform/ turn to wire
structure - crystalline lattice same type atoms
Metals Alloy
Aluminium
- Soft/malleable
Metals Vs Alloy
Alloy
•Mixture metals / non metal
•Property alloy far superior than its element/metal
•Stronger, harder and enhanced qualities than metals
structure - crystalline lattice different atomic sizes
Duralumin (Aluminium + Copper)
✗ Strong aircraft
✓
✗
Vs
Vs
Iron
- Soft/malleable
Steel
- Strong/Hard
Malleable (hammer) Ductile (Stretch)
Mixture of metals
in lattice
✓

22. Metals Alloy
✗ ✓
✗
Heating mixture metals together
Alloy cool/solidifies, mechanical property diff from its individual constituents
Metals/non-metals often enhance its properties.
Induce strength/hardness by occupying empty spaces bet lattice structure
Metals
•Same type of elements/atom arrangement
•Malleable – shaped by hammering
•Ductile –deform/ turn to wire
structure - crystalline lattice same type atoms
Aluminium
- Soft/malleable
Click here for list of alloys
Metals Vs Alloy
Alloy
•Mixture metals / non metal
•Property alloy far superior than its element/metal
•Stronger, harder and enhanced qualities than metals
structure - crystalline lattice different atomic sizes
Duralumin (Aluminium + Copper)
Strong aircraft
Vs
Vs
Iron
- Soft/malleable
Steel
- Strong/Hard
What makes
alloy strong?
Metal occupy spaces
in between
Heat mixture metals
Malleable (hammer) Ductile (Stretch)
Mixture of metals
in lattice
Strong + hard
✓
Click here uses alloy - nitinol robot

23. Metals
Structure - crystalline lattice same type atoms
Metals Vs Alloy
Property alloy far superior
than its element/metal
+
Structure - crystalline lattice different atomic sizes
Vs
Malleable (hammer) Ductile (Stretch) Mixture of metals
in lattice
Same type atom
arrangement
Ductile –
Deform/turn to wire
Malleable –
Shaped by hammer
Alloy
Mixture metals/non metal
Stronger, harder- enhance qualities than metals
✓
Metal + Metal = Alloy
✓

24. Metals
Same type atom
arrangement
Ductile –
Deform/turn to wire
Malleable –
Shaped by hammer
Structure - crystalline lattice same type atoms
Metals Vs Alloy
Property alloy far superior
than its element/metal
+
Structure - crystalline lattice different atomic sizes
Vs
Malleable (hammer) Ductile (Stretch) Mixture of metals
in lattice
Alloy Component Property/Uses
Steel Iron + Carbon Structural material
Stainless steel Iron + Carbon +Nickel +Chromium Corrosion resistance
Brass Copper + Zinc Decorative
Bronze Copper + Tin Coins and medals
Duralumin Aluminium + Copper + Manganese Aircraft
Nichrome Nickel + Chromium Heating element
Pewter Tin + Copper + Antimony Decorative
Nitinol Nickel + Titanium Shape memory,
actuator
Bold – Base main metal used
Alloy
Mixture metals/non metal
Stronger, harder- enhance qualities than metals
✓
Metal + Metal = Alloy
Steel Stainless steel Brass Bronze
Click here different alloys
Types of Alloy
✓
Pewter
Duralumin Nichrome
Click here uses alloy - nitinol robot

25. Crystalline Structure
Giant metallic Giant Ionic Giant Covalent
Network
Simple Molecular
Non Polar Polar molecule H2 Bonding
Particles Atoms(Metals)
Na, K, Li, Ca, Mg
Ion (+ve/-ve ions)
Na+CI-, K+CI-Atoms
from Gp4
(Carbon/Silicon)
Molecules with Molecule with Molecule with H atom
- Similar EN value - Different EN value - bonded to N, O, F
- Bond polarity cancel – Dipole moment (electronegative atom)
- Symmetrical - Asymmetrical
Bonding Lattice of positive
ions with sea of
electrons
Electrostatic forces
attraction bet +ion
with electron
Lattice of positive
and negative ions
Electrostatic forces
attraction bet +ion
with -ion
Giant covalent
throughout 3D
structure.
Within molecule Within molecule Within molecule
-strong covalent - strong covalent - strong covalent
Between molecule Between molecule Between molecule
-weak intermolecular - weak intermolecular - weak intermolecular
-VDF - VDF - VDF
- Dipole-dipole - Dipole -dipole
- H2 bonding
Physical
Property
State
Solid
(Non volatile)
Solid
(Non volatile)
Solid
(Non volatile)
Liq/Gas Liq/Gas Liq/Gas
(Volatile) (Volatile) (Volatile)
Melting
Point
HIGH HIGH VERY HIGH Very Low Very Low Very Low
Conduct Good Conductor
-free moving
electron
Good conductor
-free moving ions in
molten/aq state
Poor conductor
- Diamond, SiO2
Semiconductor
- Graphite, C60
Good conductor
- Graphene
Poor conductor Poor conductor Poor conductor
Solubility Insoluble Soluble in polar
solvent
Insoluble Soluble in polar Soluble in non polar Soluble in polar solvent
solvent solvent
Sea electrons +ve / -ve ions
Metallic Bonding Ionic Bonding Strong Covalent
✓
CI CI
CI CI
.... CI CI
...
...
Between
Within molecule
molecule
....
Between
molecule
Within
molecule
H2 Bonding
Carbon atoms
Silicon atoms

26. Acknowledgements
Thanks to source of pictures and video used in this presentation
Thanks to Creative Commons for excellent contribution on licenses
http://creativecommons.org/licenses/
Prepared by Lawrence Kok
Check out more video tutorials from my site and hope you enjoy this tutorial
http://lawrencekok.blogspot.com