2.3.1 Allotropes of carbon: diamond, graphite, graphene

• What are allotropes?

  Different forms of the same element
• What are the three main allotropes of carbon and their structures?

  • Diamond: Forms a strong 3D network
  • Graphite: Forms layers that can slide
  • Graphene: Forms a single layer of carbon atoms
• How many main allotropes does carbon have?

  Three
• What does the tetrahedral arrangement in diamond create?

  A strong and rigid crystal lattice
• What pattern do carbon atoms form within each layer of graphite?

  Hexagonal pattern
• How could graphene be used in electronic devices?

  • Transistors and integrated circuits
  • Transparent conductive coatings
  • Flexible electronics
  • Sensors
• What is the structure of graphite primarily made of?

  Hexagonal layers of carbon atoms
• What is the structure shown in the image?

  The image shows a graphene sheet, which is a two-dimensional lattice of carbon atoms arranged in a hexagonal pattern.
• How are the layers in graphite held together?

  By strong covalent bonds
• What do the blue points in the graphite diagram represent?

  Carbon atoms
• What are the key structural features of nanotubes?

  • Cylindrical structures composed of carbon atoms
  • Can accommodate impurities, such as in coal
• How does the arrangement of atoms/molecules in this crystal lattice differ from an amorphous solid?

  In a crystal lattice, the atoms/molecules are arranged in a highly ordered, repeating 3D pattern, while in an amorphous solid they are randomly arranged with no long-range order
• What are the three main allotropes of carbon mentioned in the image?

  Diamond, graphite, amorphous carbon
• What are the three main allotropes of carbon?

  Diamond, graphite, and graphene
• What are the distinct properties of diamond, graphite, and graphene?

  • Diamond:
  • Structure: 3D network
  • Hardness: Very hard
  • Conductivity: Insulator
  • Transparency: Transparent
  • Graphite:
  • Structure: Layered
  • Hardness: Soft, layered
  • Conductivity: Conducts electricity
  • Transparency: Opaque
  • Graphene:
  • Structure: Single layer
  • Hardness: Strong, flexible
  • Conductivity: Conducts electricity
  • Transparency: Translucent
• Why is diamond ideal for drill bits and cutting tools?

  Because of its hardness
• Why can layers in graphite slide over each other easily?

  Due to weak van der Waals forces
• What property of graphite makes it useful in pencils?

  Its soft, layered structure
• What is the structure shown in the image?

  • The structure shown is a crystal lattice
  • It consists of a repeating pattern of atoms or molecules arranged in a 3D grid
• How does the structure of diamond differ from that of graphite?

  Diamond has a 3D network, graphite is layered
• What are the key structural features of buckyballs?

  • Spherical structures composed of carbon atoms
  • Graphical adapted from Wikimedia Commons graphic created by Michael Ströck
• What is the defining characteristic of amorphous carbon?

  Pores can accomodate impurities, such as in coal
• What is the hardness of graphite compared to diamond?

  Graphite is soft, while diamond is very hard
• What type of structure does diamond form?

  Giant network structure
• How do the van der Waals forces in graphite differ from the covalent bonds?

  Van der Waals forces are much weaker than covalent bonds, allowing the layers to slide past each other
• Why do different allotropes of carbon have unique properties?

  Due to their different bonding arrangements
• How does the structure of graphite contribute to its properties?

  • The layered structure and weak van der Waals forces allow the layers to slide past each other, making graphite soft and slippery
  • The delocalized electrons in the covalent bonds allow graphite to conduct electricity
  • The strong covalent bonds within the layers make graphite very hard and resistant to compression
• How many carbon atoms is each carbon atom in diamond bonded to?

  Four carbon atoms
• What are the main components of the graphite structure shown in the image?

  • Carbon atoms
  • Van der Waals forces
  • Covalent bonds
• How are the carbon atoms arranged in the graphene lattice?

  In a hexagonal pattern
• What type of chemical bonds hold the carbon atoms together in the graphite structure?

  Covalent bonds
• What connects adjacent layers in graphite?

  Weak van der Waals forces
• What is the transparency of graphene?

  Graphene is translucent
• If you wanted to use carbon to conduct electricity, which allotrope would be most suitable?

  Graphite
• What are the key features of graphite's structure?

  • Structure consists of parallel layers
  • Carbon atoms form hexagonal pattern within each layer
  • Layers can easily slide over each other due to weak forces
  • Blue points in diagram represent carbon atoms
• What are the different allotropes of carbon mentioned?

  Diamond, graphite, graphene, fullerenes
• If you wanted to use graphite as a lubricant, which property of its structure would be most important?

  The weak van der Waals forces between the layers, allowing them to slide past each other
• How do the bonding patterns of diamond and graphite differ, and how does this affect their properties?

  Diamond has 4 bonds per carbon atom, making it super strong, while graphite has 3 bonds per carbon atom and shared "extra" electrons allowing it to conduct electricity
• If the lattice parameter (distance between adjacent atoms/molecules) is $a =$$0.5 \text{ nm}$, what is the volume of the unit cell?


  • Volume of unit cell = $a^3 =$$0.5^3 =$$0.125 \text{ nm}^3$
• How does the structure of graphite differ from the structure of diamond, and how does this affect their properties?

  Graphite has a layered, hexagonal structure with weak van der Waals forces between the layers, making it soft and slippery, while diamond has a tetrahedral, cubic structure with strong covalent bonds, making it very hard and an insulator