Giant Covalent Structures
Allotropes of Carbon:
An allotrope is a form of the same element with a different structure.
Sometimes the covalent bonds in a compound can extend throughout the whole structure to
form a giant covalent structure, called a macromolecule.
Diamond, graphite, graphene and fullerenes are all allotropes of carbon.
Diamond:
Each carbon is bonded to 4 other carbon atoms to form a giant 3d
structure.
Diamond has a high melting point due to each molecule being
held together by strong covalent bonds, and so lots of energy is
needed to overcome them.
Diamond doesn’t conduct electricity because it doesn’t contain delocalised electrons or ions
that are free to move.
Diamond is hard/strong because it is held together by strong covalent bonds in a 3d
structure.
Graphite:
Each carbon is bonded to 3 other carbon atoms, which
form hexagonal layers.
There are weak intermolecular forces
between these layers.
Graphite has a high melting point because the carbon
atoms are held together by strong covalent bonds which
take lots of energy to overcome.
Allotropes of Carbon:
An allotrope is a form of the same element with a different structure.
Sometimes the covalent bonds in a compound can extend throughout the whole structure to
form a giant covalent structure, called a macromolecule.
Diamond, graphite, graphene and fullerenes are all allotropes of carbon.
Diamond:
Each carbon is bonded to 4 other carbon atoms to form a giant 3d
structure.
Diamond has a high melting point due to each molecule being
held together by strong covalent bonds, and so lots of energy is
needed to overcome them.
Diamond doesn’t conduct electricity because it doesn’t contain delocalised electrons or ions
that are free to move.
Diamond is hard/strong because it is held together by strong covalent bonds in a 3d
structure.
Graphite:
Each carbon is bonded to 3 other carbon atoms, which
form hexagonal layers.
There are weak intermolecular forces
between these layers.
Graphite has a high melting point because the carbon
atoms are held together by strong covalent bonds which
take lots of energy to overcome.
