carbon and its allotropes

• Carbon is the most abundant element in living organisms, making up about 18% by weight.
• Diamond has a high melting point due to strong covalent bonds between atoms.
• Diamond has a tetrahedral structure with strong covalent bonds between atoms.
• The four main forms of carbon are diamond, graphite, fullerenes (buckyballs), and nanotubes.
• Graphite has layers of hexagonal rings held together by weak van der Waals forces.
• Graphite has weak intermolecular forces that allow it to be easily exfoliated into individual layers called graphene.
• Fullerenes are hollow spherical molecules made of carbon atoms arranged in hexagonal rings.
• Buckminsterfullerene (C60) is a type of fullerene that resembles a soccer ball.
• Graphite is used as an electrical conductor and lubricant.
• Diamond is the hardest known material and is used in cutting tools and jewelry.
• Carbon, symbolized as C, has an atomic number of 6 and an atomic mass of 12.
• The electronic configuration of carbon is 1s^2, 2s^2, 2p^2.
• Carbon has a valency of 4.
• Carbon occurs both in free state (graphite, diamond) and combined state (CO2, organic compound, bicarbonates, carbonates).
• Some elements are found in nature in different physical states (form) but with similar chemical properties.
• The phenomenon of the existence of an element in two or more different forms, which have different physical properties but similar chemical properties is known as its allotropes and the phenomenon is known as allotropy.
• Allotropes of carbon are classified into two classes: Crystalline form and Amorphous form.
• Diamond is a crystalline form of carbon where all the C-atoms are sp3 hybridized and arranged tetrahedrally by forming three-dimensional networks of covalent bonds having each angle 109 0 28 ' and each C-C bond length 1.54A 0.
• Diamond is the hardest substance known, has high melting and boiling point, and is a good conductor of heat and electricity.
• Diamond changes to graphite above 1800 0 C.
• Graphite has two dimensions layer structure where each carbon atom is sp2 hybridized C-atom by forming planar hexagonal rings with each bond angle 120 0 and each C-C bond length is 1.42A 0.
• In graphite, one layer can slide down over other which makes it soft, slippery in nature.
• In graphite, only three valence electrons are used to form covalent bond, due to the presence of one free electron in each C-atom graphite acts as good conductor of heat and electricity.
• Graphite is a grey-black, soft crystalline with metallic luster, is so soft that it’s soapy to touch and marks the paper, hence it is also called ‘black lead’.
• The softness and conductivity of graphite can be explained on account of its structure.
• Graphite is used in the manufacture of lead pencils, in making electrodes, as a lubricant in the form of aqua-dag or oil-dag, to make crucibles and as a resistance in electric furnaces.
• Fullerenes are a new allotropic form of carbon discovered by Kroto and Smalley in 1985, named as Buckminister fullerenes due to the shape designed by R. Buckminister.
• The most common fullerene is C 60, which contains 60 C-atom, has a spherical shape and is also called Bucky ball.
• Fullerenes have a polygon system which contains fused five or six member rings of C-atom, each C-atom is sp 2 hybridized, are covalent in nature and soluble in organic solvent.
• Other forms of Fullerene are C 32, C 50, C 70, C 76, C 84.
• Fullerene is used as a super conductor, to manufacture new type of polymer, as a sieve (tube like structure), and as a resistance in electric furnaces.
• Coal is a hard black solid combustible substance that is obtained naturally by the carbonization process, used as fuel, in the manufacture of graphite, coke, gas carbon, coal gas, etc., and is used to manufacture synthetic petrol by catalytic hydrogenation.
• Charcoal is a black, soft, lightweight, and highly porous amorphous, allotropic form of carbon, usually produced by slow pyrolysis, used as fuel, as an adsorbent, for the purification of drinking water, and is also used for refining sugar.
• Activated charcoal, a form of carbon which increases the surface area available for adsorption or chemical reaction, has a surface area in excess of 3000m ², is mainly used to manufacture gas mask, is used in the manufacture of gun power for blasting in mines, and is used in qualitative analysis of basic radical.
• Lamp black is obtained when natural gas and other carbon compounds are burnt in a limited supply of air, it is black, soft, velvety powder, used as a black paint, for manufacturing shoe polish, and is also used as a pigment in paints.
• Gas Carbon is a dense form of deposited carbon on the interior part of gas retort during the manufacture of coal gas, is a good conductor of heat and electricity.
• Graphite is lighter than diamond (spgr =2.2) and is good conductor of heat and electricity.
• Graphite resists the effect of heat and isn’t acted upon by dilute acids or alkalis.
• Coke is a grey, hard and porous substance with high carbon content and few impurities obtained as residue after the destructive distillation of coal or oil in absence of air.
• Coke is used as a fuel and as a reducing agent in metallurgy.