Giant covalent

• What are giant covalent structures like?

  They are covalent bonds formed when atoms share a pair of electrons.
• What is the structure of giant covalents?

  billions of atoms held together in a lattice structure.
• What are the properties of giant covalents?


  -high melting/boiling point.

  -they aren't soluble in water.

  -They can't conduct electricity (except graphene and graphite).
• Where are giant covalents found?

  In few non metal elements and compounds.
• What are some allotropes of carbon?

  Diamond, graphite, graphene, fullerenes.
• What is the structure of fullerenes?

  -molecules of carbon and hollow spheres and closed tubes.

  -mainly hexagonal rings of carbon atoms.

  -'cage' (form around another atom/molecule to be trapped) other molecules to deliver a drug directly to cells in the body.

  -huge surface area to make great industrial catalysts.
• Give an example of fullerenes.

  Buckminsterfullerene:

  -they have a molecular formula of carbon 60.

  -have covalent bonds.

  -stable molecule that forms soft brownish-black molecules.

  
  

  Nanotubes:

  -tiny cylinders of graphene to conduct electricity.

  -high tensile strength to strengthen materials without adding much weight.
• What is the structure of graphene?

  -sheets of carbon atoms (one atom thick) joined together in hexagons.

  -strong covalent bonds.
• What are the properties of graphene?

  -high electrical conductivity since electrons are free to move.

  -high thermal conductivity.

  -mechanical strength.

  -flexibility.

  -transparency.

  -large surface area.
• What is the structure of diamond?

  -4 strong covalent bonds

  -hard and rigid lattice in a tetrahedral arrangement.
• What are the properties of diamond?

  -electrical insulators but cannot conduct electricity as there are no free electrons.

  -High melting/boiling points.
• What is diamond useful for?

  -useful as a tool to cut things due to its hard shape.
• What is the structure of graphite?

  -3 covalent bonds.

  -no strong covalent bonds so free to move due to weak forces.

  -weak forces of attraction.
• What are the properties of graphite?

  -high melting/boiling point as covalent bonds need lots of energy to break.

  -conducts electricity as each carbon atom has one delocalised electron to move out of 3/4 electrons that are used in bonds.
• What is graphite useful for?

  Held together weakly so free to move over each other which makes graphite soft and slippery so it is ideal as a lubricating material.