allotropes of carbon

• give properties of silica

  very high melting point,

  a giant covalent structure

  linked to other atoms by strong covalent bonds which must be overcome in boiling or melting
• propeties of diamond


  form of the element carbon

  giant covalent structure

  each carbon atom forms bonds with four other carbon atoms

  does not conduct electricity as there are no free ions or electrons.
• what type of network does diamond have

  tetrahedral network
• why is diamond hard with a high melting point

  many covalent bonds to overcome
• what are allotropes


  different structural forms of the same element in the same physical state
• name carbon allotropes


  diamond

  graphite,

  graphene

  fullerene
• properties of graphite


  each carbon atom bonds with three other carbon atoms forming layers of hexagonal rings.

  the layers are held together by weak intermolecular forces so they can move over eachother making it brittle.

  graphite is soft and sippery making it a good lubricating material.
• does graphite or diamond have a higher melting point

  graphite has a high melting point due to its weak intermolecular forces requiring reasonable amounts of energy to break. However, diamond has a higher melting point because it has one more covalent bond per carbon atom present.
• can graphite conduct electricity?

  yes as only three of its four electrons are used in bonding ,meaning it has a delocalised electron that is free to move which can carry charge
• why can layers in graphite slide

  weak intermolecular forces between layers (no covalent bonds)
• why is this different to diamond

  each carbon atom is covalently bonded to four others so no electrons are free to move.
• whats graphene


  a single layer of graphite
• properties of graphene


  carbon atoms joined together in hexagonals in 2D

  strong but lightweight

  useful in electronics and composites

  conducts electricity due to delocalised electrons

  high melting points as lotds of energy is needed to overcome the covalent bonds.
• properties of fullerenes


  molecules of carbon atoms with hollow shapes

  structure based on hexagonal rngs of carbon but may alo contain rings with five or seven cabon atoms
• what was the first fullerene to be discovered

  buckmister fullerene with a spherical face