Allotropes of Carbon | 21 Nov 2024

Source: TH 

Why in News?

Carbon and its allotropes remain in news due to its varied physical and chemical properties. 

• Allotrope refers to one or more forms of a chemical element that occur in the same physical state. 
• Carbon has four main allotropes namely Diamond, Graphite, Fullerenes, and Graphene. 
  • Additionally, carbon nanotubes and amorphous carbon (like charcoal) are also considered forms of carbon, but they are less commonly classified as primary allotropes.  

What are the Allotropes of Carbon? 

• Graphite: In graphite, each carbon atom forms bonds with three other carbon atoms, creating two-dimensional sheets. It is made up of layers of Carbon atoms arranged in hexagonal arrays. 
  • Electricity Conduction: Graphite is a good conductor of electricity due to the existence of delocalised electrons within its layers. 
  • Lubricant: Its layers can easily slide over each other, making it suitable as a solid lubricant. 
  • Hardness: Graphite is the softest carbon allotrope. 
  • Graphene: Graphene is a single, one atom thick layer of graphite. It has vast potential in electronics, energy storage, sensors, coatings, composites, and biomedical devices. 
    • Its high surface area and biocompatibility make it ideal for drug delivery and tissue engineering. 
• Diamond: It is made up of a three-dimensional network of Carbon atoms arranged in a tetrahedral structure, where each carbon atom is bonded to other four carbon atoms.  
  • Hardness: It is recognized as the hardest naturally occurring material due to its strong covalent bonds, making it suitable for industrial cutting, drilling, and grinding applications. 
  • Transparency: Some diamonds exhibit high transparency in the visible spectrum, making them valuable in jewellery. 
  • Thermal Conductivity: Diamonds possess excellent thermal conductivity, making them useful in heat sinks. 
  • Electricity Conduction: It lacks electrical conductivity in its pure form as it has no free electrons or "charge carriers" available to conduct electricity. 
  • Lab-grown Diamonds (LGDs): LGDs are identical to natural diamonds in terms of physical properties such as hardness, sparkle, and durability but are created artificially in laboratories using Graphite as a diamond seed.  
• Fullerene: Buckminsterfullerene is a type of fullerene with the formula C60 and is characterised by its distinctive cage-like structure resembling a football. 
  • Applications: Fullerenes and their compounds have potential applications as semiconductors, superconductors, lubricants, catalysts, electric wires, and plastic reinforcing fibres. 
• Carbon Nanotubes: They are cylindrical structures made of rolled-up graphene sheets.  
  • They are used in electronics, materials science, energy storage, medical applications, sensors, water purification, drug delivery, aerospace, and nanotechnology. 
  • They can be used as carriers of drugs and antigens in the human body and biochemical sensors. 
  • They are biodegradable in nature. 
• Amorphous Carbon: It refers to various forms of carbon lacking a crystalline structure, such as charcoal, soot, and activated carbon.