Allotrope is the different elemental form of any atom having the same chemical but differing in physical property. Now discuss the allotropes of the carbon atom.
The list of examples of carbon allotropes are –
Crystalline
Crystallines are those allotropes that have a particular shape or geometry of a carbon atom. Crystalline allotropes have a particular shape so it has different physical property like refracting index, melting point, density, etc. But the chemical property remains the same.
Diamond
All the carbon in the diamond is sp3 hybridized. It consists of an innumerable number of tetrahedral units and the distance between lattices is 1.54Å. It Has thermal conductivity but not electricity. Dimond burns by oxygen to produce carbon dioxide at 800-9000C as it is another form of carbon
Diamond has a very high refractive index, 2.417 and for this reason, the light can pass through it and experience total internal reflection many times and appears to be shiny and lustrous
Graphite
Only graphite is a non-metal which can conduct electricity. Graphite consists of two adjacent parallel layers of C-C hexagon unit having a distance of 3.35 Å. The layers are weakly held by the van der Waal’s force so one layer can slide over another, for this reason, graphite is soft and lubricating.
Each carbon in graphite is sp2 hybridized. It is a planar hexagon and two-dimensional layer structure. The other electrons of C are present in the unhybridized p orbital, so graphite can participate in the π bond.
Fullerene
Fullerene can behave as a superconductor even at very low temperatures like 10-40K. Different types of Fullerenes are listed below.
- C60 Fullerene which is icosahedron shaped with 60 vertices. It has 32 faces, 12 pentagons, and 20 hexagons.
- C70 Fullerene which is a cage-like bucky ball shape. It has 12 pentagons and 25 hexagons
- Fullerenol which is like a radical sponge and soluble in water and has great antioxidant properties.
Amorphous
Amorphous is that allotrope of carbon that does not have a particular shape or lattice structure. Amorphous has also lattice structures but they are disorganized so they do not adopt a particular shape or structure. Their physical property is different but has the same chemical property.
Charcoal
Charcoal is used as gun powder and black paint. It is also used as fuel. Now various type of charcoal are discussed below,
| Charcoal | Vegetable Charcoal | Animal Charcoal |
| 1 | Wood Charcoal | Bone Charcoal |
| 2 | Sugar Charcoal | Blood Charcoal |
Lamp black or Carbon black
The nature of lamp black allotrope is black sooty smoke, which usually comes out after the condensation. Lamp black is the purest form of all. It is a very poor conductor of heat as well as electricity. When methane is burned then lamp black is also produced. It is is used for shoe polish and black paints.
Coke
Coke is produced by the subjective distillation of anthracite coal. It has two types, which are listed below,
- It contains about 96% of carbon atoms.
- At the higher temperature of 1000-12000C, hard coke is obtained
- At the lower temperature of 600-6500C we get soft coke.
- Hard coke is versatile in use as fuel and reductant
- soft only for domestic fuel purposes.
Gas carbon
The black hard dense residue deposited on the relatively cooler upper part of the retort is known as gas carbon. It possesses thermal and electrical conductivity. Gas carbon is widely used as electrodes in electrolysis and arc light. It is the true amorphous form of carbon. It has delocalized π electrons opposite to graphite.
FAQs
1. Diamond is unreactive whereas graphite is reactive. Why?
The lattice structure of carbon is tighter than graphite. Let us explain the reactivity of diamond and graphite in the following section.
The diamond is less reactive than graphite because diamond is more tightly packed system, where much more interaction of van der Waal’s force is present but in the case of graphite, there are weak forces present. There are delocalized π electrons present in the unhybridized p orbital, making more reactive.
Diamond consists of many tetrahedral units whereas in graphite there are two parallel units are present and they lie upon one another. So, diamond has a close-packed structure and graphite has an open structure prone to chemical attacks.
2. Fullerene act as a wonderful lubricant – why?
Fullerene is made by different numbers of a cluster of carbon atoms. Now discuss the lubricant nature of the fullerene.
Fullerene is a wonderful lubricant because the van der Waal’s attraction between several clusters of fullerene is very weak, so one can slide over another. Also fullerene is made of different five or six-member carbon clusters, those can easily move from one to another and makes fullerene slippery.
For this reason, fullerene is slippery. Of this slippery nature, it can behave as a lubricant.
Conclusion
The property of showing allotropes is known as allotropy, and this property is shown by carbon due to the catenation property and π bond formation. This allotropic form is of two types one is crystalline based on a particular shape and structure and another is amorphous having not a particular shape.
Hi……I am Biswarup Chandra Dey, I have completed my Master’s in Chemistry from the Central University of Punjab. My area of specialization is Inorganic Chemistry. Chemistry is not all about reading line by line and memorizing, it is a concept to understand in an easy way and here I am sharing with you the concept about chemistry which I learn because knowledge is worth to share it.