The Structure of Graphite
- GIANT covalent structure
- The distance between the layers is about 2.5 times the distance between the atoms within each layer.
- Each carbon atom uses
- three of its electrons to form simple covalent bonds with other carbon atoms. The fourth electron in each carbon becomes delocalised – they are no longer associated with any particular atom.
- As the
delocalised electrons move around the sheets of graphite, very large temporary dipoles form which will induce other dipoles in the sheets above and below throughout the whole graphite crystal.
- The atoms in each sheet, held together by
covalent bonds, are stronger than diamonds because of the bonding caused by the delocalised electrons.
You have to know how to draw the structure of Graphite and Diamond as they are asked in AS/A-level Chemistry exam. 👨🏫
Properties of Graphite
- Has a
- high melting point as strong covalent bonds and need to be broken throughout the whole crystal.
- Has a
- low density because of the space ‘wasted’ in-between the sheets.
- Insoluble
as attractions between solvent molecules and carbon atoms will never be strong enough to overcome the covalent bonds.
- Conducts electricity as the delocalised electrons are free to carry charge
across the sheets.
The Structure of Diamond
- Each carbon atom is covalently bonded to four other carbon atoms – forming four single bonds.
- It is a
- giant covalent structure – a macromolecular crystal.
- Has no delocalised electrons.
Make sure your know how to draw the structures, practice makes perfect!!
Properties of Diamond
- Has a v
- ery high melting point as there are very strong carbon-carbon covalent bonds throughout the structure.
- It is very
- hard because of the three dimensional covalent bonds.
- Does not conduct electricity as there are no electrons which are free in order to carry the charge.
- Insoluble
as there are no possible attractions which could occur between solvent molecules and carbon atoms which could outweigh the attraction between the covalently bound carbon atoms.
Reference:
This is the end of the topic!
Drafted by Cherry (Chemistry)