Structures (chemistry)

• Giant ionic structures are large structures in regular patterns that are held together by strong electrostatic forces of attraction. They have oppositely charged ions. The forces of attraction act in all directions and this makes them very hard to break and have high melting and boiling points.
• If enough energy is put in and a giant ionic structure changes state to a liquid, it can conduct electricity. This is because now the ions are free to move around in the liquid and so can carry a charge. Many giant ionic structures will dissolves in water because the lattice is split up by the water molecules.
• A double covalent bond means that there is two pairs of electrons. A triple covalent bond means that there is three pairs of electrons.
• Diamond is a giant covalent structure. It is made up of carbon entirely. Diamond and graphite are two examples of carbon allotropes (different versions).
• Each carbon in diamond is bonded to 4 others. This means that diamond cannot conduct heat or electricity because there are no delocalised electrons to carry a charge/heat. It is very hard and has a high melting and boiling point because it has strong covalent bonds.
• Graphite is made up of carbon. Each carbon is joined to 3 others so there is a delocalised electron that can carry a charge, so graphite can conduct electricity and heat. They have high melting and boiling points because they have strong covalent bonds. They have weak forces between each layer so graphite is soft and slippery and can be used as a lubricant.
• Fullerenes are also carbon allotropes. They are hollow spheres made of carbon atoms.
• The fullerene C60 is called Buckminsterfullerene. It was named after Richard Buckminster Fuller who designed geodesic domes which look like this shape.
• Fullerenes have high tensile strength, which can be used to reinforce materials. They have high tensile strength because they are strong covalently bonded.
• Fullerenes can conduct electricity and heat because they have a delocalised electron. They are spherical shaped and so can be used as a lubricant. They are good catalysts because of their huge surface area to volume ratio.
• Fullerenes are used in medicine because:

  They aren’t reactive

  They aren’t toxic to the body

  They are small enough to fit inside of cavities

  They can act as shields or tubes to deliver drugs to specific areas of the body
• Nano particles are very small particles that are 1-100 nanometers in size. They have a large surface area to volume ratio.
• Applications of nano particles:

  Fabrics-to kill bacteria and keep clothes fresh

  Medicine-carry drugs to specific areas

  Electronics-prevents growth of microorganisms

  Cosmetics-they are absorbed deeper into the skin

  Sun creams-they absorb UV radiation

  Catalysts-used in fuel cells to speed up the rate of reaction
• Downsides of nanoparticles applications:

  Medicine-higher danger with a higher diameter

  Electronics-unknown danger if it gets into the atmosphere

  Cosmetics-particles could enter the bloodstream

  Sun creams-not completely sun-proof

  Catalysts-could cause an explosion if large amount is near a spark