Giant covalent bonding

What are giant covalent molecules at room temp

Always solid, as giant covalent molecules have millions of strong covalent bonds. They always have high melting and boiling points

Examples of giant covalent molecules

Diamond

Silicon dioxide

Graphite

What are diamond formed from

Carbon

Structure of diamond

Each carbon atom forms 4 covalent bond with 4 other carbon atoms.

A single diamond contains a huge amount of carbon atoms joined by covalent bonds

Melting and boiling point of diamond

Very high, because they have a huge number of covalent bonds

Melting point is over 3700 degree Celsius

Electrical conductivity of diamond

diamond cannot conduct electricity

There are no free electrons to carry electrical charge

Structure of silicon dioxide

Contains oxygen atoms and silicon atoms covalently bonded.

Melting and boiling point of silicon dioxide

Very high, because a huge number of strong covalent bonds must be broken and this requires a great deal of energy

What did graphite made from

Carbon

Properties of graphite

High melting and boiling point

Soft and slippery

Excellent conductor of both electricity and heat

Structure of graphite

Formed from carbon

Each carbon atom forms three covalent bonds. Carbon atoms form hexagonal rings. The hexagonal rings are in layers. There are no covalent bonds between the layers so they can slide, making graphite slippery

Why do graphite have a high melting and boiling point

Because graphite has many strong covalent bonds, it takes a great deal of energy to break these

Why is graphite an excellent conductor of heat and electricity

Each carbon atom has one electron not in a covalent bond. These electrons are released from the carbon atoms. Delocalised electrons can move. This means they can conduct thermal energy (heat) and electricity.

Is graphite a metal

No, as it is based on the element carbon

How is graphite similair to metals

Both graphite and metals are good conductors of heat and electricity. This is as both have delocalised electrons that can move

What is graphene

A single layer of graphite

How thick is graphene

1 atom thick

Electrical conductivity of graphene

Excellent conductor because it had delocalised electrons

Property of graphene

Strong, making it useful for future materials

What are fullerenes

Molecules of carbon atoms with hollow shapes

Structure of fullerenes

Usually have hexagonal rings of carbon atoms.

However, fullerenes can also have rings with five or seven carbon atoms

Why is the first fullerene we discovered

Buckminsterfullerene (C60)

What do buckminsterfullerenes contain

60 carbon atoms in a hollow sphere. Carbon Atoms form rings with either 6 carbon atoms or 5 carbon atoms

Uses of fullerenes

Pharmaceutical delivery

Lubricants

Catalysts

What are carbon nanotubes

Fullerenes shaped into long cylinders. Have rings containing 6 carbon atoms

Properties of carbon nanotubes

High tensile strength (can be stretched without breaking)

Excellent conductors of heat and electricity

Use of carbon nanotubes

Reinforce materials such as in tennis rackets