An element possessing different physical forms of existence is known as allotropes of that element.
The three allotropes of carbon are:
Diamond is a colourless transparent substance having extraordinary brilliance.
Diamond is quite heavy.
Diamond is extremely hard. It is the hardest natural substance known.
Diamond does not conduct electricity.
Diamonds can be artificially made by subjecting pure carbon to very high pressure and temperature. These are called synthetic diamonds.
Diamonds are used in cutting instruments like glass cutters, saw for cutting marble and in rock drilling equipment.
Diamonds are used for making jewellery.
Graphite is a greyish-black opaque substance.
Graphite is soft and slippery to touch.
Graphite conducts electricity.
The softness of graphite helps in the making of lubricant for fast moving parts of machinery.
As Graphite is a good conductor of electricity, it helps in the making of electrodes or graphite electrodes in dry cells and electric arcs.
Graphite helps in developing cores of pencils i.e. pencil leads and black paints.
An allotrope of carbon-containing clusters of 60 carbon atoms joined together to form spherical molecules is Buckminsterfullerene.
Its formula is C60 (C- sixty).
Buckminster-fullerene is a football-shaped spherical molecule.
It has 60 carbon atoms rearranged into interlocking hexagonal and pentagonal rings of carbon atoms.
Buckminsterfullerene is a dark solid at room temperature.
HOW DOES BUCKMINSTERFULLERENE DIFFER FROM DIAMOND AND GRAPHITE?
It differs from the other two allotropes of carbon which are diamond and graphite.
While diamond and graphite are giant molecules with unending network of carbon atoms, buckminsterfullerene is a very small molecule made up of only 60 carbon atoms.
Buckminsterfullerene is neither very hard nor soft.
REASON FOR THE LARGE NUMBER OF ORGANIC COMPOUNDS (OR CARBON COMPOUNDS)
The two characteristic properties of carbon element leading to the formation of a large number of organic compounds (or carbon compounds) are:
Tetravalency (four valencies)
REASONS FOR THE EXISTENCE OF A LARGE NUMBER OF ORGANIC COMPOUNDS OR CARBON COMPOUNDS:
Catenation: Carbon atoms link with one another by means of covalent bonds forming long chains (or rings) of carbon atoms. So, catenation is the property of carbon element where atoms can join with one another to form long carbon chains.
Tetravalency: The four valency of carbon is another reason for the existence of a large number of organic compounds (or carbon compounds).