Allotropes of carbon
Allotropes of carbon
The various physical forms in which an element can exist are called allotropes of the element. The carbon elements exists in three solid forms called allotropes. The three allotropes of the carbon are -
(1) Diamond
(2) Graphite
(3) Buckminster fullerene
(1) Diamond
Diamond is a colourless transparent substance having extraordinary shining. Diamond is quite heavy. Diamond is extremely hard. It is the hardest natural substance known. Diamond does not cunduct electricity. Diamond burns on strong heating to form carbon dioxide. If we burn diamond in Oxygen , then only CO2 gas is formed and nothing is left behind. This shows that diamond is made up of carbon only.
Structure of Diamond -
A Diamond crystal is a very big molecule of carbon atoms. Each carbon atom in the diamond crystal is linked to four other carbon atoms by strong covalent bonds. The four surrounding carbon atoms are at the four vertices of a regular tetrahedron.
The diamond crystal is, therefore, made up of carbon atoms which are powerfully bonded to one another by a network of covalent bonds. Due to this, diamond structure is very rigid. The rigid structure of Diamond makes it a very hard substance. The compact and rigid three dimensional arrangements of carbon atoms in diamond gives it a high density. The melting point of diamond is also very high. Diamond is a non conductor of electricity.
Uses of Diamond -
(1) Diamonds are used in cutting instruments like glass cutters, saw for cutting marble and in rock drilling equipment.
(2) Diamonds are used for making jewellery.
(3) Sharp edged diamonds are used by eye surgeons as a tool to remove cataract from eyes with a great precision.
(2) Graphite
Graphite is a greyish - black opaque substance. Graphite is lighter than diamond. Graphite is soft and slippery to touch. Graphite conductes electricity. Graphite burns on strong heating to form carbon dioxide. If we burn graphite in Oxygen,then only carbon dioxide gas is formed and nothing is left behind. This shows that graphite is made up of carbon only.
Structure of graphite -
The structure of graphite is very different from that of diamond. A graphite crystal consists of layers of carbon atoms or sheets of carbon atoms.
Each carbon atom in a graphite layer is joined to three other carbon atoms by strong covalent bonds to form flat hexagonal rings. The various layers of carbon atoms in graphite are quite far apart so that no covalent bonds can exist between them. The various layers of carbon atoms in graphite are held together by weak van der Waals forces. Due to the sheet like structure, graphite is a comparatively soft substance. Graphite is a good conductor of electricity , due to the presence of free electrons .
Uses of Graphite-
(1) Due to its softness, powdered graphite is used as a lubricant for the fast moving parts of the machinery.
(2) Graphite is used for making carbon electrodes in dry cells and electric arcs.
(3) Graphite is used for making the cores of our pencils called pencil leads and black paints.
(3) Buckminster fullerene
Buckminster
fullerene is an allotrope of carbon Containing clusters of 60 carbon
atoms joined together to form spherical molecules. Since there are 60
carbon atoms in a molecule of Buckminster fullerene ,so its formula is
C60
( C- sixty ) .
Structure of Buckminster fullerene -
Buckminster fullerene is a dark solid at room temperature. Just like diamond and graphite, Buckminster fullerene also burns on heating to form carbon dioxide. If we burn Buckminster fullerene in Oxygen then only carbon dioxide is formed and nothing is left behind. This shows that buckmbuckmi is made up of carbon only. Buckminster fullerene is neither very hard nor soft.
Other properties of Buckminster fullerene are still being investigated.
The various physical forms in which an element can exist are called allotropes of the element. The carbon elements exists in three solid forms called allotropes. The three allotropes of the carbon are -
(1) Diamond
(2) Graphite
(3) Buckminster fullerene
(1) Diamond
Diamond is a colourless transparent substance having extraordinary shining. Diamond is quite heavy. Diamond is extremely hard. It is the hardest natural substance known. Diamond does not cunduct electricity. Diamond burns on strong heating to form carbon dioxide. If we burn diamond in Oxygen , then only CO2 gas is formed and nothing is left behind. This shows that diamond is made up of carbon only.
Structure of Diamond -
A Diamond crystal is a very big molecule of carbon atoms. Each carbon atom in the diamond crystal is linked to four other carbon atoms by strong covalent bonds. The four surrounding carbon atoms are at the four vertices of a regular tetrahedron.
The diamond crystal is, therefore, made up of carbon atoms which are powerfully bonded to one another by a network of covalent bonds. Due to this, diamond structure is very rigid. The rigid structure of Diamond makes it a very hard substance. The compact and rigid three dimensional arrangements of carbon atoms in diamond gives it a high density. The melting point of diamond is also very high. Diamond is a non conductor of electricity.
Uses of Diamond -
(1) Diamonds are used in cutting instruments like glass cutters, saw for cutting marble and in rock drilling equipment.
(2) Diamonds are used for making jewellery.
(3) Sharp edged diamonds are used by eye surgeons as a tool to remove cataract from eyes with a great precision.
(2) Graphite
Graphite is a greyish - black opaque substance. Graphite is lighter than diamond. Graphite is soft and slippery to touch. Graphite conductes electricity. Graphite burns on strong heating to form carbon dioxide. If we burn graphite in Oxygen,then only carbon dioxide gas is formed and nothing is left behind. This shows that graphite is made up of carbon only.
Structure of graphite -
The structure of graphite is very different from that of diamond. A graphite crystal consists of layers of carbon atoms or sheets of carbon atoms.
Each carbon atom in a graphite layer is joined to three other carbon atoms by strong covalent bonds to form flat hexagonal rings. The various layers of carbon atoms in graphite are quite far apart so that no covalent bonds can exist between them. The various layers of carbon atoms in graphite are held together by weak van der Waals forces. Due to the sheet like structure, graphite is a comparatively soft substance. Graphite is a good conductor of electricity , due to the presence of free electrons .
Uses of Graphite-
(1) Due to its softness, powdered graphite is used as a lubricant for the fast moving parts of the machinery.
(2) Graphite is used for making carbon electrodes in dry cells and electric arcs.
(3) Graphite is used for making the cores of our pencils called pencil leads and black paints.
(3) Buckminster fullerene
( C- sixty ) .
Structure of Buckminster fullerene -
Buckminster
fullerene is a football shaped spherical molecule in which 60 carbon
atoms are arranged in interlocking hexagonal and pentagonal rings of
carbon atoms. There are 20 hexagons and 12 pentagons of carbon atoms in
one molecule of Buckminster fullerene .
This allotrope was named Buckminster fullerene after the American
architect Buckminster Fuller because its structure resembled the
framework of domeshaped halls designed by Fuller for large international
exhibitions .
Buckminster fullerene is a dark solid at room temperature. Just like diamond and graphite, Buckminster fullerene also burns on heating to form carbon dioxide. If we burn Buckminster fullerene in Oxygen then only carbon dioxide is formed and nothing is left behind. This shows that buckmbuckmi is made up of carbon only. Buckminster fullerene is neither very hard nor soft.
Other properties of Buckminster fullerene are still being investigated.
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