Grade 9
  1. Matter and its nature  1.1. Introduction to matter  1.2. Physical and chemical properties of matter  1.3. States of matter  1.3.1. Solid state  1.3.2. Fluid state  1.3.3. Gaseous state  1.3.4. Plasma and Bose–Einstein condensate  1.4. Changes in the states of matter  1.4.1. Melting and freezing  1.4.2. Evaporation and Condensation  1.4.3. Sublimation and deposition  1.5. Classification of matter  1.6. Elements, Compounds, and Mixtures  1.7. Pure substances and impurities  1.8. Separation Techniques  1.8.1. Filtration  1.8.2. Distillation  1.8.3. Crystallization  1.8.4. Chromatography  1.8.5. Centrifugation  1.8.6. Sublimation  1.8.7. Decantation and sedimentation
  2. Atomic Structure  2.1. Discovery of atoms  2.2. Dalton's atomic theory  2.3. Structure of the atom  2.4. Subatomic particles  2.5. Atomic number and mass number  2.6. Isotopes and Isobars  2.7. Electronic configuration  2.8. Bohr's atomic model  2.9. Modern Atomic Model (Quantum Mechanical Model - Introduction)  2.10. Valency and chemical bonding
  3. C hemical reactions and equations  3.1. Introduction to Chemical Reactions  3.2. Chemical Equation Formulation  3.3. Balancing Chemical Equations  3.4. Types of Chemical Reactions  3.4.1. Combination Reactions  3.4.2. Decomposition reactions  3.4.3. Displacement reactions  3.4.4. Double displacement reactions  3.4.5. Redox reactions  3.4.6. Endothermic and Exothermic Reactions  3.5. Effects of chemical reactions  3.6. Energy Changes in Chemical Reactions  3.7. Catalysts and their role in reactions
  4. Periodic table and periodicity  4.1. History of Periodic Classification  4.2. Mendeleev's periodic table  4.3. Modern Periodic Table  4.4. Periods and groups in the periodic table and periodicity  4.5. Trends in the Periodic Table  4.5.1. Atomic size  4.5.2. Ionization Energy  4.5.3. Electron affinity  4.5.4. Electronegativity  4.5.5. Metallic and Non-Metallic Properties  4.6. Noble gases and their properties
  5. Chemical bond  5.1. Introduction to Chemical Bonding  5.2. Types of chemical bonds  5.2.1. Ionic bond  5.2.2. Covalent bond  5.2.3. Metallic bond  5.2.4. Hydrogen bonding  5.2.5. Van der Waals force  5.3. Properties of Ionic and Covalent Compounds  5.4. Molecular Structure and Geometry (VSEPR Theory - Basics)
  6. Acids, Bases and Salts  6.1. Introduction to Acids and Bases  6.2. Properties of Acids  6.3. Properties of bases  6.4. pH scale and its importance  6.5. Indicators and their uses  6.6. Neutralization reactions  6.7. Strength of Acids and Bases (Strong vs. Weak)  6.8. Preparation of salts  6.9. Uses of acids, bases and salts in daily life
  7. Metals and Nonmetals  7.1. Physical Properties of Metals  7.2. Physical Properties of Nonmetals  7.3. Chemical properties of metals  7.4. Chemical Properties of Nonmetals  7.5. Reactivity Series of Metals  7.6. Extraction of metals  7.7. Corrosion and its prevention  7.8. uses of metals and nonmetals
  8. Carbon and its compounds  8.1. Introduction to Carbon  8.2. Allotropes of carbon (diamond, graphite, fullerene)  8.3. Hydrocarbons  8.3.1. Hydrocarbons  8.3.2. Alkene  8.3.3. Alkynes  8.4. Functional groups in organic chemistry  8.5. Isomerism in organic compounds  8.6. Alcohols and Carboxylic Acids  8.7. Soaps and detergents  8.8. Polymers (Introduction to Natural and Synthetic Polymers)
  9. Solutions and Mixtures  9.1. Types of mixtures  9.2. Homogeneous and Heterogeneous Mixtures  9.3. Concentration of solutions  9.4. Solubility and factors affecting solubility  9.5. Suspensions and Colloids  9.6. Saturated, unsaturated and supersaturated solutions
  10. Air and atmosphere  10.1. Composition of air  10.2. Role of gases in the atmosphere  10.4. Acid rain and its effects  10.5. Greenhouse effect and global warming  10.6. Ozone layer and its depletion  10.7. Air pollution control measures
  11. Water and its importance  11.1. Composition and properties of water  11.2. Hardness of water (temporary and permanent hardness)  11.3. Causes of water pollution  11.4. Effects of Water Pollution  11.5. Water purification methods (filtration, boiling, chlorination)
  12. Industrial Chemistry  12.1. Introduction to Industrial Chemistry  12.2. Important industrial chemicals (sulfuric acid, ammonia, sodium hydroxide)  12.3. Chemical processes in industry  12.4. Uses of Industrial Chemistry in Daily Life  12.5. Environmental impact of industrial chemical processes

Grade 9 → Carbon and its compounds ↓


Allotropes of carbon (diamond, graphite, fullerene)


Carbon is a fascinating element, mainly because it is able to form a wide variety of allotropes. Allotropes are different structural forms of the same element, an interesting phenomenon that leads to very different physical and chemical properties. In this lesson, we will explore three important allotropes of carbon: diamond, graphite, and fullerenes, which include C 60 and related structures.

What is carbon?

Carbon is a chemical element with the symbol C and atomic number 6. It is a nonmetal and tetravalent, meaning it can form four bonds with other atoms. Carbon is essential to life, as it forms the backbone of organic chemistry.

Understanding allotropes

Allotropes are different forms of the same element in the same physical state. These differences arise from the way the atoms in each form are bonded together. Different allotropes have different physical and chemical properties as a result of the bonding. For carbon, its ability to form or link long chains and different structures plays an important role in the variety of its allotropes.

Diamond

Diamond is probably the best-known allotrope of carbon, renowned for its luster and hardness.

Diamond structure

The carbon atoms in diamond are arranged in a crystal lattice structure known as the diamond cubic lattice. Each carbon atom is covalently bonded to four other carbon atoms in a tetrahedral geometry:

C
   /|
  C C C
   |/
    C

This strong covalent bond causes diamond to be extremely hard, making it useful for cutting tools and abrasives. This tetrahedral structure is symmetrical and spread throughout the crystal, which accounts for diamond's various properties.

Properties of diamond

  • Hardness: Diamond is the hardest natural substance, rated at 10 on the Mohs hardness scale.
  • Transparency: Diamonds are usually transparent and can be quite brilliant when cut correctly.
  • Electrical bad conductor: Since all valence electrons are used in covalent bonding, diamond does not conduct electricity.
  • Thermal conductivity: Interestingly, diamond is a good conductor of heat.

Graphite

Graphite is another allotrope of carbon, but it exhibits very different properties than diamond.

Structure of graphite

The carbon atoms in graphite are bonded together in layers of a hexagonal lattice. Each layer is made up of carbon atoms bonded in a plane with a honeycomb pattern:

C C C
  / 
 C   C
   /
    C C C

Each carbon atom is bonded to three others in a plane, leaving one electron free to conduct electricity. These layers are held together by weak van der Waals forces, allowing them to slide easily over one another. This is responsible for the smooth feel of graphite and its use as a lubricant.

Properties of graphite

  • Softness: Graphite layers can slide over each other, making it soft and slippery.
  • Electrical conductor: Due to the presence of free electrons, graphite can conduct electricity.
  • High melting point: Despite being soft, graphite has a very high melting point due to the strong covalent bonds within the layers.
  • Opaque: Graphite is not transparent and its colour is dark and shiny.

Fullerenes

Fullerenes are relatively recent additions to the family of carbon allotropes. They are molecules composed entirely of carbon, shaped as a hollow sphere, ellipsoid, or tube. The most famous fullerene is buckminsterfullerene (C 60), which resembles a soccer ball:

Some other forms of fullerenes include carbon nanotubes and graphene.

Composition of C60

The C60 molecule has 60 carbon atoms arranged in a structure that includes pentagons and hexagons, similar to a soccer ball. This gives it a nearly spherical shape, providing symmetrical bonds that provide stability.

Properties of fullerenes

  • Electrical properties: Fullerenes can act as semiconductors.
  • Strength: This arrangement provides remarkable strength, especially in tubular arrangements such as carbon nanotubes.
  • Reactivity: Fullerenes can react with other chemicals, making them useful in a variety of applications, including drug delivery systems.

Applications of carbon allotropes

Applications of diamond

Due to its hardness, diamond is widely used in cutting, grinding, and drilling tools. It also has important uses in electronics and high-precision scientific equipment. Additionally, the optical properties of diamond make it desirable for jewelry.

Applications of graphite

Graphite is used as a lubricant due to its slippery layers. Its ability to conduct electricity makes it useful in batteries and as an electrode in electrolysis. In addition, the high melting point of graphite makes it ideal for use as a refractory material in high-temperature applications.

Applications of fullerenes

The use of fullerenes is promising in the fields of medicine, electronics, and materials science. Their unique properties make them suitable for use as MRI contrast agents, drug delivery systems, and superconductors.

Conclusion

Carbon's ability to form such diverse allotropes is an extraordinary example of chemical versatility. From shiny diamond to smooth graphite and fascinating fullerenes, each allotrope has unique properties, resulting in a wide variety of applications. Understanding carbon's allotropes not only explains how this element works in different environments, but also how it can be used in technology and industry to solve complex problems.


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Introduction to Carbon
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Hydrocarbons

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Allotropes of carbon (diamond, graphite, fullerene)

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