Allotropes are different structures of the same element, which also happen to exhibit different physical and chemical characteristics. A commonly known example is carbon. Carbon can come in the form of diamond, graphite, graphene, and fullerene.
Diamond has a giant covalent structure, a basic idea is that each carbon atom has all of its four bonds occupied. It is in a regular arrangement and is in the shape of a tetrahedral. This makes diamond an extremely hard material, thus giving it a high boiling and melting point. However, it does not have any delocalized electrons so electricity cannot pass through it, hence making it a bad electrical conductor. Diamond is commonly used to cut other hard objects as the tip of a drilling tool.
Graphite on the other hand only uses three of its bonds which means it has a delocalized electron. This gives it the ability to conduct electricity. Graphite is arranged in a layered manner, this means that each layer can get shaved away, as it does in pencils. This also leads to the next point which is that it has very weak London dispersion forces. London dispersion forces are existent between all molecules, and they are very week forces. These give each layer the opportunity to remove itself, as there is a weak attraction between these molecules. Graphite feels soft and slippery so it can also be used as a lubricant, for example in factories.
Graphene is a form of graphite, however, it is only one layer rather than many. Since graphite has strong covalent bonds between each of the carbon atoms, this gives graphene a lot of strength and a high melting point. Again, due to the delocalized electron graphene has excellent electrical conductivity. They can be used for electronics and composites. In fact, Samsung has released a statement in 2019 stating they had planned to make a graphene phone battery. This is because graphene is a lot more effective in conducting electricity than copper and hence, would reduce the time it took to charge a phone. It states that “in theory, …[a graphene battery] requires only twelve minutes to fully charge.”
The next allotrope of carbon is known as fullerene or C60, it is usually in a spherical shape and has a simple structure. It is called a truncated icosahedron as it is composed of twenty hexagons and twelve pentagons in the form of carbon rings. Throughout these hexagons and pentagons, only three carbons are bonded. There are two different types of fullerenes; buckminsterfullerene and nanotubes. The buckminsterfullerene was the first ever to be discovered and its molecule is made of sixty carbon atoms held together by covalent bonds, making them very strong. Although the actual structure is hard, the intermolecular forces between molecules are weak and thus they have a low melting point. Nanotubes on the other hand have a cylindrical form and they have high length to diameter ratios. They have pretty similar properties with graphene, such as electrical conductivity and it is used a lot for nanotechnology. Nanotubes have a lot of tensile strength and so they don’t stretch a lot.
Silicon is an element in the periodic table that is neither a metal nor a non metal. It is a poor electrical conductor because of its strong covalent bonds. It can bond with four other silicon atoms, giving it a tetrahedral shape with a bond angle of 109.5˚. The electrical conductivity can be increased by a process called doping. This consists of adding small amounts of phosphorus or boron to pure silicon.
Silicon dioxide is structured in the same way as diamond as they are both giant covalent structures. There are four oxygen atoms bonded to a silicon atom, it is a very hard substance. Unlike what many people think, sand is not pure silicon dioxide, rather, an impure form of it. It is a yellowish colour because iron is present within it. Both silicon and silicon dioxide exceed melting points of 1400˚ C because of their strong covalent bonds. A lot of energy is required to break these bonds, thus giving it a high melting point.
As we can see carbon has four allotropes, all of which have different uses and different physical and chemical properties. Therefore, we can say that carbon is an extremely versatile element as it can be used for many different reasons. From diamond jewellery to graphite led, it is able to easily adapt. This is due to the fact that carbon can not only form single, double, and triple bonds but also branched chains and rings.
Versatile Carbon, www.chemeddl.org/resources/TSTS/McMahon/McMahon9to12pg/VersitaleCarbon.html.
Yurtoğlu, Nadir. “Http://Www.historystudies.net/Dergi//Birinci-Dunya-Savasinda-Bir-Asayis-Sorunu-Sebinkarahisar-Ermeni-isyani20181092a4a8f.Pdf.” History Studies International Journal of History, vol. 10, no. 7, 2018, pp. 241–264., doi:10.9737/hist.2018.658.