Giant Molecular Structures
|Structure||All carbon atoms connected to each other by very strong covalent bonds in a 3 dimensional structure.Each carbon atom is bonded to 4 other carbon atoms by very strong covalent bonds.|
Also applicable to SiO2.
|Flat layers of carbon atoms. Each carbon atom is connected to 3 other atoms by strong covalent bonds in a 2 dimensional hexagonal structure.|
|Electrical conductivity||Diamond does not conduct electricity |
Each carbon atom uses up its 4 valence electrons for bonding with 4 other carbon atoms.
No free electrons to move and conduct elec.
|Graphite can conduct electricity |
In each layer, a carbon atom is bonded to 3 other carbon atoms, leaving 1 valence electron free.
These electrons are delocalized, can travel along the layers, and conduct electricity.
|Hardness or softness||Giant molecular structure held together by very strong covalent bonds. A lot of energy required to break all these bonds hence diamond is hard.||Consist of layers of carbon atoms held together by very strong covalent bonds.Attractive forces between layers is weak, hence layers can slide past one another, making graphite soft.|
|Melting point||Very high melting point |
Giant molecular structure with millions of carbon atoms held together by very strong covalent bonds.
A large amount of energy is needed to break these bonds -> high m.p.
|Very high melting point. |
Layers of carbon atoms held together by strong covalent bonds. A lot of energy needed to break these bonds -> high m.p.