Structure

Describe the structure of diamond

• Giant covalent structure

• Each carbon forms 4 sigma bonds to 4 others

• Giant 3D tetrahedral arrangement

Explain the electrical conductivity and strength of diamond

• Does not conduct as there are no free electrons or ions

• Hard as carbon forms 4 bonds, rigid structure preventing any movement

Describe the structure of graphite

• Each carbon forms 3 sigma bonds to 3 others

• The 4th electron in the p orbital, close enough to overlap so delocalised electrons are above and below layers

• Weak forces between layers

Explain the electrical conductivity and strength of graphite

• High conductivity as there are delocalised electrons between layers which are free to move - only conduct to parallel layers

• Soft due to weak london forces between layers which are easily broken so layers can slide

What is graphene

One layer of graphite

Describe the strength of graphene

Strong but can be fractured

Describe the structure (bonds) of silicon dioxide

• Each silicon forms 4 bonds with oxygen atoms

• Each oxygen forms 3 bonds with silicon atoms

Explain the electrical conductivity and strength of silicon dioxide

• does not conduct electricity as there are no free electrons or ions

• Hard as forms a rigid structure

Describe the structure of C60 fullerene

• Each carbon forms 3 bonds

• The 4th electron is delocalised over surface

• Balls can slide over each other as only weak forces between balls

• Simple molecular structure

Explain the boiling point and electrical conductivity of C60 fullerene

• Low BP due to weak intermolecular forces between molecules

• Low conductivity as electrons cannot move between balls