BLACK & WHITE COMPARISON

Graphite

Diamond

Why are diamonds extremely hard?

Why can graphite conduct electric current?

Graphite has delocalised electrons, just like metals. These electrons are free to move between the layers in graphite, so graphite can conduct electricity. ... The forces between the layers in graphite are weak. This means that the layers can slide over each other.

The heat and pressure causes the diamonds molecules to change so that they're so close together, the molecules can't move (known as covalent bonding). The closeness of these molecules forms a rigid bond, therefore making the diamond hard.

Graphite has a giant covalent structure in which: each carbon atom is joined to three other carbon atoms by covalent bonds, the carbon atoms form layers with a hexagonal arrangement of atoms, the layers have weak forces between them, each carbon atom has one non-bonded outer electron, which becomes delocalised

Diamond has a giant covalent structure in which: each carbon atom is joined to four other carbon atoms by covalent bonds, the carbon atoms have a regular lattice arrangement, there are no free electrons